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Links between traits of interest and breeding practices: Several pathways for farmers’ decision making processes
Livestock Science 220 (2019) 158–165
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Livestock Science journal homepage: www.elsevier.com/locate/livsci
Links between traits of interest and breeding practices: Several pathways for farmers’ decision making processes
T
⁎
Lola Peruchoa, , Christina Ligdab, Jean-Christophe Paolia, Ioannis Hadjigeorgiouc, Charles-Henri Moulind, Anne Lauvied a
INRA, UR 0045 Laboratoire de Recherches sur le Développement de l'Elevage, Quartier Grossetti, 20250 Corte, France Hellenic Agricultural Organization, Veterinary Research Institute, P.O. Box 60 272, 57 001, Thessaloniki Greece c Department of Nutrition Physiology and Feeding, Faculty of Animal Sciences and Aquaculture, Agricultural University of Athens, 75 Iera Odos, 11855, Athens, Greece d UMR Systèmes d’élevage Méditerranéens et Tropicaux (SELMET), INRA – CIRAD – MontpellierSupAgro – Univ Montpellier, 2 place Pierre Viala, 34060 Montpellier cedex 1, France b
A R T I C LE I N FO
A B S T R A C T
Keywords: Local breeds Sheep Corsica Thessaly Replacement Culling
Assessing farmers’ preferences for animal traits is increasingly used in studies of the implementation of breeding programs, to make sure breeding objectives fit farmers’ expectations. However, these studies have a major limitation: it is difficult to identify the links between farmers’ traits of interest (TOI) and the farmers’ decision making process for the management of flock performance through replacement, culling, purchase of breeding animals and choice of the breeds or their crosses. A comprehensive approach to farmers’ preferences was applied through 81 semi-structured interviews with dairy sheep farmers in Corsica (France, n = 39) and Thessaly (Greece, n = 42). In each region, TOIs were identified as traits motivating the use of a given farming practice and listed and quantified according to this definition. Milk yield, milk persistence, udder conformation and sensitivity to diseases including mastitis were major TOIs in both regions. Improvement of flock performance for a TOI was obtained through the use of this TOI or a correlated TOI as a replacement criterion or other breeding practices such as culling and the use of breed(s). The role of the internal replacement process in the improvement of flock performance varied according to the genetic context of the area (purebred farming, coexistence of several breeds and crossbred animals) and the TOI considered. The findings of this study should help better define priorities for breeding objectives in local breeding schemes. The results provided new insights into the categories of variables to be taken into consideration in studies on farmers’ preferences for TOIs.
1. Introduction Assessing farmers’ preferences for animal traits is said to be useful when insufficient production data are available to calculate the economic value of breeding objective traits using bio-economic models or profit functions (Byrne et al., 2012; Nielsen et al., 2014). Adjusting breeding objectives to farmers’ expectations might also increase farmers’ participation in breeding programmes. For instance, farmers’ attitudes towards risk management (Kulak et al., 2003 cited by Nielsen et al., 2014), farmers’ trade-offs between production and functional traits in response to specific socio-economic factors, as well as farmers’ perception of any correlation between traits, probably influence the use of breeding indexes at farm scale (Byrne et al., 2012;
Nielsen et al., 2014). Such factors are assumed to be indirectly taken into account through the analysis of farmers’ stated or revealed preferences. In existing studies on farmers’ preferences for animal traits, the link between the ‘trait of interest’ variable (TOI) and the farmers’ decision making process for the management of flock performance is scarcely investigated. Indeed, TOIs are often considered per se (e.g. Byrne et al, 2012) or strictly assimilated to selection criteria (e.g. Gomes Arandas et al., 2017; Ndumu et al., 2008). When selection criteria and TOIs are distinguished, results rarely succeed in identifying the link between them (e.g. Bett et al., 2009; Ilatsia et al., 2012). However, knowledge of this link can help identify the breeding objective of a future breeding programme. Moreover, in the literature, the breed is taken into account
Abbreviations: TOI, Trait of interest; PDO, Protected Denomination of Origin; LW, Live weight; OS Brebis Corse, Breeding scheme of the Corsican breed ewe; KGBZ, Livestock Genetic Resources Center of Thessaly; DRAAF, Regional Directorate for Food, Agriculture and Forestry ⁎ Corresponding author. E-mail addresses: [email protected] (L. Perucho), [email protected] (C. Ligda). https://doi.org/10.1016/j.livsci.2018.12.017 Received 12 March 2018; Received in revised form 9 November 2018; Accepted 15 December 2018 1871-1413/ © 2018 Elsevier B.V. All rights reserved.
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in different ways such as the breed(s) comprising the flock or the breed traits preferred by farmers (e.g. Nauta et al., 2009; Zander and Drucker, 2008; Martin-Collado et al., 2015). However, these studies do not clearly explain how farmers use the breed lever for the management of flock performance. To address these issues, we conducted a comprehensive analysis of the farmers’ decision making process in on-farm practices. The on-farm practices considered included the following breeding practices: internal replacement, culling, purchase of breeding animals and choice of the breed(s). Traits of interest (TOIs) were defined as traits motivating any on-farm practice. The objective of the study was to demonstrate that farmers manage flock performance for specific TOIs (i) through one or several of the above-mentioned breeding practices (ii) using their perception of correlations between different TOIs. The analysis was performed on dairy sheep farms in two Mediterranean regions, one in the South of France (Corsica) and one in central Greece (Thessaly). The two regions were chosen for the contrasted use of the dairy sheep breeds raised there. The Corsican breed is the main sheep breed in Corsica, whereas a variety of local and exotic breeds coexist in Thessaly in purebred and crossbred flocks.
breeds such as the Lacaune, Assaf and Awassi breeds. The Karagouniko breed, the main local breed in the region is raised on semi-extensive lowland farms. The breed is tall (58–68 cm shoulder height and 45–60 kg LW in females), with a white fleece and black spots on the head and feet with black and white variants (Hatziminaoglou, 2001). This dairy breed has a prolificacy of 1.45 (FAO, 2018) and its average annual milk yield in 2014 was 165 L/ewe for 133 milking days (data from KGBZ). The Chios breed is a dairy breed raised on more intensive farms in Thessaly (Gelasakis et al., 2010) and is tall (an average of 73 cm wither height and 60 kg LW for females), with a white fleece spotted with black areas on the head, belly and feet, high prolificacy (1.9) and high productivity (Hatziminaoglou, 2001; FAO, 2018). Finally, other local breeds in Thessaly are small population breeds, including Kalarritiko (with the largest number of transhumant flocks), and Piliou and Skopelos, making up only a few flocks restricted to certain locations.
2.3. Sampling and data collection A survey of 81 dairy sheep farms was conducted between 2014 and 2016 in Corsica (n = 39) and Thessaly (n = 42). We did not aim to get a representative sample of the farmer population but to maximize the diversity of farming systems likely to influence farmers' preferences for breeds and animal traits. The sample was obtained through non-probability sampling in two steps. For the first round of the survey, a small number of farms (n = 26 in Corsica and n = 23 in Thessaly) was identified based on the previous characterization of regional production systems completed by regional databases and information from professionals in the sector. The criteria for this first sampling of farms in Corsica and Thessaly were flock size, type of grazing areas and cultivated areas, practice of transhumance, milking method, geographical location and participation in a breeding scheme. Other criteria for the sampling were also used in the first round of the survey depending on the data available, or if they made specific sense in the region (i.e. onfarm cheese processing in Corsica, flocks in a breed conservation programme in Thessaly). The first round was then completed by snowball sampling (n = 13 in Corsica and n = 19 in Thessaly), which is a “nonprobability method of survey sample selection that […] relies on referrals from initially sampled respondents to other persons believed to have the characteristic of interest.” (Johnson, 2014). For this purpose, farmers in the first round were asked for contacts who fulfilled the criteria for sampling not adequately covered in the first round. Data were collected by the same operator in face-to-face semistructured interviews with farmers. The average duration of an interview was two hours. The farmers’ responses were recorded by notes taken by the operator throughout the interview. The interview consisted of a general part concerning the characterization of the farm and a second part focusing on understanding the farmers’ breeding practices. In the second part, farmers were asked how they choose males and females for replacement and culling. Moreover, farmers were interviewed about the adoption of their particular breed flock
2. Material and methods 2.1. Study areas Dairy sheep farming in Corsica and Thessaly highly contributes to the economic outputs of the regional livestock activity, through the production of PDO cheeses or whey-cheese and several local cheeses. In Corsica, about a third of the sheep milk produced is processed on-farm (DRAAF Corse, 2017), while on-farm cheese processing for commercial purposes is seldom practiced in Thessaly. The situation of the genetic resources at the regional level is different in each region, as it is the case for calendar(s) of milk collection at the farm scale. Milking methods are diverse in both regions. Finally, in both regions, dairy sheep farming includes the use of native grazing lands under a Mediterranean climate and the use of transhumance in a minority of farms. In such pastoral farming conditions, the capacity for adaptation and the hardiness of the animals are likely to rank among farmers’ preferences. These main farming conditions are presented in Table 1. 2.2. Description of main local breeds The Corsican breed ewe is a small dairy breed of the island of Corsica (an average of 55 cm wither height and 35 kg LW for females) with coarse wool, horns and multi-variant fleece colours (FAO, 2018). The breed is considered as rustic, well-adapted to extensive farming thanks to its walking ability, has low prolificacy (1.15, AgroParisTech, 2007), high fat and proteins content in milk (7.1% fat and 5.57% protein in 2014) and an average annual milk yield of 162 L/ ewe for 185 milking days in 2016 (data from OS Brebis Corse). In Thessaly, several local breeds and local populations coexist with exotic Table 1 Context and characteristics of dairy sheep farming in Corsica and Thessaly. Corsica
Thessaly
Breed composition Breeding scheme
Corsican breed ewe Regional breeding scheme
Milking methods Main production calendar Climate Vegetation of main grazing lands Topography Transhumance
Hand and machine milking Autumn lambing and milk production until summer Mediterranean Scrublands Combination of lowlands, hilly and mountain ranges Yes (minority of farms) Short and medium distance
Purebred and crossbred flocks Indigenous and exotic breeds Regional breeding scheme Hand and machine milking Different lambing seasons and periods of production Mediterranean Scrublands and grasslands Combination of lowlands, hilly and mountain ranges Yes (minority of farms) Short to long distance
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composition (Thessaly) and about the providers of breeding animals (Thessaly and Corsica). Information on the content of the interview grid is available in Online Resources 1 and 2.
Table 2 TOIs identified in Corsica and Thessaly. Traits of interest (TOIs)
Dairy and meat yield Milk yield Milk persistence Longevity Milk quality Meat yield Meat quality Feed intake Ability to feed Feed conversion Reproduction Suckling ability Prolificacy Deseasoning Development of male sexual organs Fertility Ability to mate Maternal behaviour Ability to lamb successfully Autonomy in lambing Adaptation to biophysical constraints Sensitivitya to mastitis Resistance to scrapie Sensitivitya to other/undefined diseases Udder depth at grazing Ability to cope with transhumance Feeding behaviour Sensitivitya to cold and humidity Sensitivitya to heat Adult hardiness Adaptation to feed restriction Walking ability Feed conversion on pastures Ability to milk rebound in spring Ability to maintain body condition Work management Ease of milking Behaviour with humans Behaviour with respect to shepherding Conformation and aesthetics Adult breed standard and aesthetics Lamb breed standard and aesthetics Adult conformation Lamb conformation Horn orientation Udder abnormalities Udder conformation (others)
2.4. Data analysis Three steps of data analysis enabled us to identify the range of TOIs and their farmers’ management processes in Corsica and Thessaly. First, TOIs were identified from the farmers’ responses and named with a generic formulation inspired by usual terms of the literature in order to facilitate comparison of their distribution between fields. Traits mentioned by farmers were considered as TOIs if they matched one or both of the following definitions: (i) a trait motivating a current on-farm practice (ii) a trait playing a role in the adoption or rejection of an alternative on-farm practice. These traits could concern individual animals, the whole flock or a specific breed or crossbreed. By on-farm practices, we mean all practices linked with the management of the flock: breeding practices, feeding, housing, batching, etc. In breeding practices, we include breed(s) choice, internal replacement (for males and for females), culling, and breeding animals purchase. The aim of using the above definition of TOI, assuming false negatives, was to ensure that all animal traits subsequently included in the analysis were indeed of interest to the farmers themselves. The objective of the second step was to assess the extent to which the TOIs were exclusively or partially used as internal replacement criteria. Internal replacement criteria are defined here as TOIs used for the choice of an ewe's offspring as a future breeding animal in the flock. The term «criteria» was chosen to emphasize the fact that replacement is a selection process aimed at transmitting the TOI to the future breeding animals. Motives of culling can cover a variety of reasons that are more difficult to distinguish: to manage on-going performance of the flock and/or to avoid transmitting these traits to the future breeding animals of the flock. Following the above-mentioned definition of TOIs, motives of culling have been translated in TOIs regardless of the reason underlying culling. For each TOI we listed: (i) the number of farms in which this TOI was used as an internal replacement criterion (ii) the set of alternative or complementary breeding practices taken into consideration by the interviewed farmers for the management of their flock performance (i.e. culling, choice of the breeds or crossbreed, use of specific sub-populations of ewes and rams purchase). Finally, the last step consisted in identifying the correlations between TOIs and the use of these correlations through the previously identified breeding practices. Correlations between TOIs were defined from farmers’ perception, i.e. as the use of a TOI as an indicator to improve another TOI.
Corsica (% of farmers)
Thessaly (% of farmers)
100 74 23 18 0 0 0 0 3
100 81 21 26 19 7 33 5 2
38 23 23 10 10 5 3 0 3
7 21 5 2 24 2 5 5 5
49 21 59 33 23 23 15 0 13 8 5 8 8 23
45 0 69 0 14 14 50 45 48 7 12 10 7 17
74 44 0
33 14 26
49 13 15 31 28 31 79
45 45 24 71 0 0 60
a In order to simplify the presentation of results, sensitivity was used as a generic term. This trait designation could mean either “affected by” or “sensitive to” (stricto sensu)
3. Results
3.2. Management of flock performance for TOIs: Diversity of levers
3.1. Traits of interest
Different levers were used by farmers to manage the performance of the flock for each TOI. These levers differed depending on the TOI and the region concerned (Table 3). Selecting males and females for internal replacement was a main lever to manage flock performance for milk yield, milk persistence, suckling ability, udder depth at grazing, ease of milking, breed standard and aesthetics (lamb and adult), lamb conformation, udder conformation and udder abnormalities. In addition, farmers could manage the flock performance for these TOIs through other breeding practices: purchase of external breeding animals on breed standard and aesthetics, culling of females on productive or udder traits, etc. On the contrary, in both regions, some TOIs were scarcely managed through internal replacement and rather managed through the choice of the breed(s), the choice of specific providers or sub-populations of ewes for the purchase of breeding animals and/or the culling of animals on their corresponding phenotypes. This is the case of milk quality and
The TOIs identified in each region and the percentage of farmers concerned are listed in Table 2. In both regions, milk yield, milk persistence, udder conformation and sensitivity to diseases were considered by more than 50% of the interviewed farmers. Adult breed standard and aesthetics, lamb conformation and ease of milking were also frequent TOIs in both regions (30–50% of the interviewed farmers), as were longevity and prolificacy to a lesser extent (20–30% of the interviewed farmers). Other TOIs were specifically important (>30% of the interviewed farmers) in Thessaly (sensitivity to climate, adult hardiness, feed intake and lamb breed standards and aesthetics) or in Corsica (behaviour with humans, udder depth at grazing, udder abnormalities as cysts and supernumerary teats).
160
23 5 – 33
23 5 –
10
23 18 –
38
23 23 10
Longevity Milk quality Feed intake Reproduction Suckling ability
Prolificacy Deseasoning Fertility
Adaptation to biophysical constraints Sensitivity to mastitis 49
161 5 – 5 3 69
33 23
23
15
– 13
23
74
44
49
13 15
Udder depth at grazing Ability to cope with transhumance
Feeding behaviour
Sensitivity to cold and humidity
Sensitivity to heat Adult hardiness
Ability to maintain body condition Work management Ease of milking
Behaviour with humans
Conformation and aesthetics Adult breed standard and aesthetics
Lamb breed standard and aesthetics Adult conformation
13 7
26
33
5
28 –
59
Sensitivity to other/undefined diseases
3
45
74
Milk persistence
92
Internal replacement criterion (% of farmers)
100
Corsica TOI (% of farmers)
Dairy and meat yield Milk yield
Trait
Motive for choosing external rams or rams providers Subpopulations of Corsican ewes or breed Motive for choosing external rams Subpopulations of Corsican ewes or breed Motive for choosing external rams
Motive for female culling Motive for choosing external rams or rams providers Subpopulations of Corsican ewes or breed Motive for female and male culling Motive for choosing rams providers
Motive for female and male culling Motive for choosing rams providers Subpopulations of Corsican ewes or breed Motive for female culling Motive for choosing rams providers Motive for female culling Subpopulations of Corsican ewes or breed Motive for choosing rams providers Motive for female culling Subpopulations of Corsican ewes or breed None Motive for choosing external rams or rams providers Motive for male culling
Motive for female culling
Motive for female and male culling Subpopulations of Corsican ewes or breed Motive for choosing rams providers Motive for choosing external rams None Motive for female culling
Motive for female culling Motive for choosing external rams or rams providers Subpopulations of Corsican ewes or breed None Subpopulations of Corsican ewes or breed None
Motive for female culling Motive for choosing external rams or rams providers
Other breeding practices used to manage flock performance for the TOI
Table 3 Management of flock performance for specific TOIs and the respective breeding practices applied by farmers.
Breed Motive for female culling Breed
–
7
14
45 24
45 –
21
21
33
45
Breed
– 17
(continued on next page)
None Motive for choosing external ram Breed
Motive for choosing external ram Breed (for aesthetics)
Breed Motive for female culling
Breed Motive for male culling
Breed Breed
– – 45 48
50
5
– –
– 14 14
–
Breed Motive for female culling Breed Motive for female culling Motive for choosing rams providers None Breed
Breed Breed Breed Motive for female culling
None
Breed Breed Breed
Breed Motive for male and female culling Motive for choosing external rams or ram providers Breed Motive for female culling
Other breeding practices used to manage flock performance for the TOI
2
69
45
5 – –
2
7
21 5 24
5 – –
45
81
21 26 33
95
Internal replacement criterion (% of farmers)
100
Thessaly TOI (% of farmers)
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Livestock Science 220 (2019) 158–165
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18 31 Udder abnormalities
feed intake (mainly through the breed lever), reproductive traits as fertility (mainly through culling) and deseasoning (mainly through flock management in Corsica and through the breed lever in Thessaly), and the majority of TOIs associated with the adaptation to biophysical constraints (several levers). In general, external purchase of breeding animals was driven by the following farmers’ rationale: in both regions, the choice of ram providers was based on confidence and geographical proximity; it aimed at limiting the risk of introducing diseases or breeding animals with low dairy potential in the flock. Moreover, in Corsica, farmers distinguished sub-populations of the Corsican breed according to their location. They associated these locations to different biophysical environments or to possible crossbreeding with the Sardinian breed. The use of breeding animals from such locations was then used to manage flock performances for TOIs linked to adaptation to the biophysical environment and to the Corsican breed or some of its subpopulations (e.g. ease of milking and suckling ability, breed standard and aesthetics). Finally, regarding trait management, the role played by the choice of the breed(s) with respect to the role of internal replacement could differ between regions. For example, internal replacement was often used in Corsica to manage the flock performance for longevity, prolificacy and behaviour with humans, whereas in Thessaly, farmers rather used the breed lever to manage these TOIs.
Results are presented for TOIs considered by at least 23% of the sampled farmers in a region (n = 9 farmers in Corsica, n = 10 farmers in Thessaly).
None – –
Breed Motive for female culling 40 60 79 Udder conformation
69
28 Horn orientation
18
Motive for male culling Motive for choosing external rams Motive for female culling Motive for choosing rams providers Subpopulations of Corsican ewes or breed Motive for female and male culling Motive for choosing rams providers
–
–
Breed Motive for male culling None 55 31 Lamb conformation
15
Motive for female culling
71
Other breeding practices used to manage flock performance for the TOI Corsica TOI (% of farmers) Trait
Table 3 (continued)
Internal replacement criterion (% of farmers)
Other breeding practices used to manage flock performance for the TOI
Thessaly TOI (% of farmers)
Internal replacement criterion (% of farmers)
L. Perucho et al.
3.3. Management of the flock performance for a TOI: Role of correlations between TOIs as perceived by farmers Among the breeding practices used to improve flock performance for a given TOI, below we refer those resulting from farmers’ perception of correlations between TOIs. These practices consisted in using an easily assessable TOI as a criterion of replacement, a motive for culling or a motive for choosing a breed, in order to improve flock performance with respect to its positively correlated TOI (Table 4). In these cases, the easily assessable TOI was a morphological TOI (lamb conformation, udder conformation, breed standard and aesthetics) or milk yield. The indirectly considered correlated TOI was then either milk yield or a TOI linked to adaptation to biophysical constraints (sensitivity to mastitis, hardiness, sensitivity to cold). A negative correlation between TOIs, as perceived by farmers, concerned sensitivity to mastitis and milk yield, and milk persistence and milk yield at peak lactation. These TOIs were used as replacement criteria: mitigating the level of selection on milk yield indirectly enabled improvement of flock performance for milk persistence and aimed at decreasing sensitivity to mastitis. 4. Discussion 4.1. An insight on farmers’ strategies Farmers used different breeding practices for the management of flock performance for different traits, according to the region and the TOIs considered. The use of one or several of these breeding practices can be understood as different farmers’ ways to deal with the complexity (or scarcity) of tools and information available for the management of their flock performance (Martin-Collado et al, 2018). For example, Thessaly hosts several exotic and indigenous breeds known or tested on-farm for their different morphological and physiological characteristics, among which longevity, prolificacy and behaviour with humans. A simplified way used by farmers to manage these TOIs in the flock was to change the breed and focus internal replacement on other TOIs. On the contrary, in Corsica, internal replacement was used by farmers to maintain these TOIs in their local purebred flocks. Likewise, farmers’ rationale for the purchase of breeding animals (confidence, location) and the use of correlation between TOIs were simplified strategies to manage flock performance for TOIs difficult to assess (e.g. ascendants’ TOIs of a ram purchased from another farm or animal hardiness). These strategies refer to the competence-difficulty gap 162
Replacement and/or culling based on udder conformation (teats, shape, size, depth) enables selection of animals based on ease of milking Choice of the breed based on udder conformation (teats, shape, depth) indirectly enables the choice of breeds easy to milk Replacement and/or culling based on udder size and/or udder shape enables selection of animals based on milk yield
Replacement and/or culling based on udder conformation (teats, depth) enables selection of animals based on suckling ability Choice of the breed based on udder conformation (teats) indirectly enables the choice of breeds with suckling ability Replacement and/or culling based on milk persistence indirectly manages flock performance with respect to sensitivity to cold Choice of the breed based on milk persistence during cold weather indirectly enables the choice of breeds with low sensitivity to cold Replacement and/or culling based on milk yield to indirectly manage flock performance for milk persistence (positive or negative correlations between the two TOIs) Replacement on milk persistence indirectly enables selection of animals based on milk yield Replacement based on thin morphology or "beautiful appearance” indirectly enables selection of animals based on milk yield Replacement based on similar morphology with ascendants indirectly enables selection of animals based on ascendant TOI including milk yield Replacement based on lamb conformation indirectly enables selection of animals based on milk yield
Ease of milkinga Udder conformation
Suckling abilitya Udder conformation
163
Replacement of external rams based on adult morphology referring to populations in central Corsica indirectly enables management of flock performance for adult hardiness Replacement based on fleece colour or breed standard referring to rustic breeds indirectly enables selection of animals based on hardiness
Adult hardiness Adult breed standard and aesthetics
Variable correlations with lamb weight and depending of breeds, litter size, and moment between birth and weaning (e.g. Slen et al., 1963; Burgos-Gonzalez et al., 2018) Variable or negligible genetic correlations with somatic cell counts/scores, depending (among other factors) on lactation stage and breed (Bergonier et al., 2003; Salaris et al., 2012; Barillet et al., 2001) Adaptation to thermal stress are linked with coat colour (through coat reflectance, Mc Manus et al, 2011), fat deposit on tails and rump, smaller ears and legs (Mirkena et al., 2010)
Variable or non-significant correlations for several body traits (e.g. Perez-Cabal et al., 2013; de la Fuente et al, 2011)
Link with milk persistence depends on the moment milk yield is assessed (total milk yield, lactation peak, t-time during lactation) (Kominakis et al., 2002; Wood equation)
Positive correlation for udder dimensions, negative or positive correlation between teat angle, teat position, teat placement (e.g. Mavrogenis et al., 1988; Labussière et al., 1981; Dzidic et al., 2004; Legarra and Ugarte, 2005; Iniguez et al., 2009) Significant link between udder type and milk suckled only at specific lactation stages (Unal et al., 2007) Significant link between low lamb weight and sub-optimal teat position (Huntley et al., 2012) Significant link between low temperatures, humidity and milk yield or milk production decay (e.g. Peana et al., 2017; Ramon et al, 2016)
Positive correlation for udder width, udder surface areas, teat position (e.g. Labussière et al., 1981; Dzidic et al., 2004)
Examples of correlations found in literature for sheep
Results are presented for correlations used at least by 3 farmers across study areas to improve flock management for a given TOI. a Replacement and/or culling based on udder depth and/or teat position enables joint selection of animals based on ease of milking and suckling ability (n = 3 farms)
Mitigating replacement based on milk yield indirectly enables selection of animals based on low sensitivity to mastitis (negative correlation)
Sensitivity to mastitis Milk yield
Milk yield Lamb conformation
Milk yield Milk persistence Milk yield Adult breed standard and aesthetics
Milk persistence Milk yield
Sensitivity to cold Milk persistence
Milk yield Udder conformation
Farmer rationale
TOI to improve TOI used as indicator
Table 4 Use of correlations between TOIs for the management of TOIs across regions.
2
8
2
7
5
5
5
7
10
13
7
13
2
21
26
31
31
Thessaly (% of farmers)
46
Corsica (% of farmers)
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4.3. Conclusion
(farmers’ knowledge of correlation between traits, farmers’ knowledge of breed traits), to recognition heuristics and one-reason decision making (basing ram purchase on the trust in the provider or on the biophysical environment of the providing farm), and social heuristics (imitating other farmers behaviour or following their knowledge of the breed) (Martin-Collado et al, 2018). Comparison between farmers’ perception of correlations between TOIs and examples of correlations found in literature (Table 4) indicated that farmers have a good knowledge on traits correlated with udder conformation (ease of milking, milk yield, suckling ability) but at some extent, the use of correlated traits might not reach its aim due to the complexity of correlations (improvement of sensitivity to mastitis through milk yield, of milk persistence through milk yield, of milk yield through lamb conformation).
Dairy sheep farmers in Corsica and Thessaly used several levers to guide the performance of their flock towards the different TOIs considered. TOIs were not automatically used as internal replacement criteria, but their expression in the flock could be achieved through other breeding practices such as the choice of the breed(s) composing the flock or the use of specific networks of ram providers. In particular, these two breeding practices were preferred for the management of flock performance for TOIs linked with the adaptation to the biophysical constraints. The breed lever could also replace the internal replacement lever when several breeds displaying contrasted phenotypes were available in the region. Finally, correlations between TOIs (as perceived by farmers) contributed to the use of these different levers to improve flock performance towards the desired way. The knowledge of the different breeding practices used by farmers to improve flock performance for TOIs will help to orientate breeding schemes towards TOIs used to be managed through the breed lever. It will also contribute in proposing adequate indicators to farmers for the selection of their internal breeding animals, according to the TOI they wish to improve. Finally, the diversity of TOI targeted by farmers through their on-farm breeding practices can be further used as a basis of discussion for participatory approaches aiming at defining common breeding objectives.
4.2. Analysing breeding practices used by farmers to manage flock performance for a TOI The comprehensive approach of farmers’ decision making processes indicated that not necessarily each TOI identified was used by the farmers as an internal replacement criterion. A stated-preference approach of farmers’ preferences could permit to complete this result by a first systematic checking of farmers’ preferences for a predefined list of TOIs (e.g. Ahlman et al., 2014) and, second, by the discussion of their potential use as internal replacement criteria. In these two steps, the current level of flock performance for a trait (Slagboom et al., 2016), the range of available selection criteria to the farmer (as suggested in Ndumu et al., (2008) through perceived values of animals), the farmers’ perception of TOIs heritability, correlations and the trade-offs performed between them (Haile et al., 2013; Bett et al., 2009) should be considered as factors influencing the use of specific internal replacement criteria. In the literature, the role of the breed is tackled through: (i) the breed(s) composing the breeding stock (as a variable illustrating farmers’ preferences for TOIs and selection criteria, e.g. Bebe et al., 2003; Martin-Collado et al., 2015; Tabbaa et al., 2009) (ii) farmers’ preferences for breeds (e.g. Nauta et al., 2009; Zander and Drucker, 2008) or for breed traits (e.g. Jabbar and Diedhiou, 2003; Mwacharo and Drucker, 2005; Wurzinger et al., 2006) (iii) the ranking of predefined traits assumed to define the breed (e.g. Bebe et al., 2003; Zander and Drucker, 2008; Zonabend Konig et al., 2015) (iv) the breed listed as a TOI or as a selection criterion (e.g. Dossa et al., 2015; Ragkos and Abas, 2015). In Corsica and Thessaly, the breed played a key role in the farmers’ decision making process for the improvement of their flock (a) through the use of the breed for crossbreeding or as a purebred flock (b) through selection based on breed standard as a replacement criterion (c) through the restriction of external supply in breeding animals to specific animal sub-populations within the breed. Consequently, analyzing the role of the breed in the improvement of flock performance would need to include the animal populations targeted through the choice of rams’ providers, and the reasons for replacing or culling animals based on the breed standard. External replacement through market transactions is often taken into account in studies of farmers preferences for TOIs (e.g. Scarpa et al., 2003; Tindano et al., 2017). Modalities of external replacement can include for example the attributes of the buyer and seller (Jabbar and Diedhiou, 2003) or the advice from providers and the prestige of the provider (Martin-Collado et al., 2015). Our results suggest that these modalities should be further investigated as simplified strategies to select breeding animals with one or several TOIs. Finally, when culling practices are investigated (e.g. Kugonza et al., 2011; Bett et al., 2009), it would be interesting to systematically specify with farmers whether or not their motives of culling aim solely at managing the on-going flock performance for a TOI or are part of a conscious strategy to avoid transmitting faulty traits to the next generation of breeding animals.
Acknowledgments This work was supported by the Domestic and Perform projects (supported by ARIMNET, ERA-Net funded by the European Union), the Department of Nutrition Physiology and Feeding of the Agricultural University of Athens and the Corsican regional research funding scheme (CPER/CTC). The authors wish to thank all the farmers and the members of regional support structures who were interviewed in Corsica and Thessaly as well as Mr. Jean-Yves Gambotti for his help in the data collection process. Conflicts of interest The authors have no conflicts of interest to declare. Supplementary materials Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.livsci.2018.12.017. References AgroParisTech, 2007. Les races ovines françaises: race ovine corse. http://www2. agroparistech.fr/svs/genere/especes/ovins/corse.htm (accessed 8 November 2018). Ahlman, T., Ljung, M., Rydhmer, L., Rocklinsberg, H., Strandberg, E., Wallenbeck, A., 2014. Differences in preferences for breeding traits between organic and conventional dairy producers in Sweden. Livest. Sci. 162, 5–14. Barillet, F., Rupp, R., Mignon-Grasteau, S., Astruc, J.M., Jacquin, M., 2001. Genetic analysis for mastitis resistance and milk somatic cell score in French Lacaune dairy sheep. Genet. Sel. Evol. 33, 397–415. https://doi.org/10.1051/gse:2001124. Bebe, O., Udo, H.M.J., Rowlands, G.J., Thorpe, W., 2003. Smallholders dairy systems in the Kenya highlands: breed preferences and breeding practices. Livest. Prod. Sci. 117–127. Bergonier, D., de Crémoux, R., Rupp, R., Lagriffoul, G., Berthelot, X., 2003. Mastitis of dairy small ruminants. Vet. Res. 34, 689–716. https://doi.org/10.1051/ vetres:2003030. Bett, R.C., Kosgey, I.S., Kahi, A.K., Peters, K.J., 2009. Analysis of production objectives and breeding practices of dairy goats in Kenya. Trop. Anim. Health Prod. 41, 307–320. Burgos-Gonzalez, C., Huerta-Aparicio, M., Aguirre, V., Vazquez, R., Orihuela, A., Pedernera, M., 2018. Short communication: milk production and lamb development in Saint Croix and Katahdin hair sheep breeds (Ovis aries). Trop. Anim. Health Prod. 50, 683–687. Byrne, T.J., Amer, P.R., Fennessy, P.F., Hansen, P., Wickham, B.W., 2012. A preferencebased approach to deriving breeding objectives: applied to sheep breeding. Animal 6, 778–788. de la Fuente, L.F., Gonzalo, C., Sanchez, J.P., Rodriguez, R., Carriedo, J.A., San Primitivo,
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Links between traits of interest and breeding practices: Several pathways for farmers’ decision making processes
T
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Lola Peruchoa, , Christina Ligdab, Jean-Christophe Paolia, Ioannis Hadjigeorgiouc, Charles-Henri Moulind, Anne Lauvied a
INRA, UR 0045 Laboratoire de Recherches sur le Développement de l'Elevage, Quartier Grossetti, 20250 Corte, France Hellenic Agricultural Organization, Veterinary Research Institute, P.O. Box 60 272, 57 001, Thessaloniki Greece c Department of Nutrition Physiology and Feeding, Faculty of Animal Sciences and Aquaculture, Agricultural University of Athens, 75 Iera Odos, 11855, Athens, Greece d UMR Systèmes d’élevage Méditerranéens et Tropicaux (SELMET), INRA – CIRAD – MontpellierSupAgro – Univ Montpellier, 2 place Pierre Viala, 34060 Montpellier cedex 1, France b
A R T I C LE I N FO
A B S T R A C T
Keywords: Local breeds Sheep Corsica Thessaly Replacement Culling
Assessing farmers’ preferences for animal traits is increasingly used in studies of the implementation of breeding programs, to make sure breeding objectives fit farmers’ expectations. However, these studies have a major limitation: it is difficult to identify the links between farmers’ traits of interest (TOI) and the farmers’ decision making process for the management of flock performance through replacement, culling, purchase of breeding animals and choice of the breeds or their crosses. A comprehensive approach to farmers’ preferences was applied through 81 semi-structured interviews with dairy sheep farmers in Corsica (France, n = 39) and Thessaly (Greece, n = 42). In each region, TOIs were identified as traits motivating the use of a given farming practice and listed and quantified according to this definition. Milk yield, milk persistence, udder conformation and sensitivity to diseases including mastitis were major TOIs in both regions. Improvement of flock performance for a TOI was obtained through the use of this TOI or a correlated TOI as a replacement criterion or other breeding practices such as culling and the use of breed(s). The role of the internal replacement process in the improvement of flock performance varied according to the genetic context of the area (purebred farming, coexistence of several breeds and crossbred animals) and the TOI considered. The findings of this study should help better define priorities for breeding objectives in local breeding schemes. The results provided new insights into the categories of variables to be taken into consideration in studies on farmers’ preferences for TOIs.
1. Introduction Assessing farmers’ preferences for animal traits is said to be useful when insufficient production data are available to calculate the economic value of breeding objective traits using bio-economic models or profit functions (Byrne et al., 2012; Nielsen et al., 2014). Adjusting breeding objectives to farmers’ expectations might also increase farmers’ participation in breeding programmes. For instance, farmers’ attitudes towards risk management (Kulak et al., 2003 cited by Nielsen et al., 2014), farmers’ trade-offs between production and functional traits in response to specific socio-economic factors, as well as farmers’ perception of any correlation between traits, probably influence the use of breeding indexes at farm scale (Byrne et al., 2012;
Nielsen et al., 2014). Such factors are assumed to be indirectly taken into account through the analysis of farmers’ stated or revealed preferences. In existing studies on farmers’ preferences for animal traits, the link between the ‘trait of interest’ variable (TOI) and the farmers’ decision making process for the management of flock performance is scarcely investigated. Indeed, TOIs are often considered per se (e.g. Byrne et al, 2012) or strictly assimilated to selection criteria (e.g. Gomes Arandas et al., 2017; Ndumu et al., 2008). When selection criteria and TOIs are distinguished, results rarely succeed in identifying the link between them (e.g. Bett et al., 2009; Ilatsia et al., 2012). However, knowledge of this link can help identify the breeding objective of a future breeding programme. Moreover, in the literature, the breed is taken into account
Abbreviations: TOI, Trait of interest; PDO, Protected Denomination of Origin; LW, Live weight; OS Brebis Corse, Breeding scheme of the Corsican breed ewe; KGBZ, Livestock Genetic Resources Center of Thessaly; DRAAF, Regional Directorate for Food, Agriculture and Forestry ⁎ Corresponding author. E-mail addresses: [email protected] (L. Perucho), [email protected] (C. Ligda). https://doi.org/10.1016/j.livsci.2018.12.017 Received 12 March 2018; Received in revised form 9 November 2018; Accepted 15 December 2018 1871-1413/ © 2018 Elsevier B.V. All rights reserved.
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in different ways such as the breed(s) comprising the flock or the breed traits preferred by farmers (e.g. Nauta et al., 2009; Zander and Drucker, 2008; Martin-Collado et al., 2015). However, these studies do not clearly explain how farmers use the breed lever for the management of flock performance. To address these issues, we conducted a comprehensive analysis of the farmers’ decision making process in on-farm practices. The on-farm practices considered included the following breeding practices: internal replacement, culling, purchase of breeding animals and choice of the breed(s). Traits of interest (TOIs) were defined as traits motivating any on-farm practice. The objective of the study was to demonstrate that farmers manage flock performance for specific TOIs (i) through one or several of the above-mentioned breeding practices (ii) using their perception of correlations between different TOIs. The analysis was performed on dairy sheep farms in two Mediterranean regions, one in the South of France (Corsica) and one in central Greece (Thessaly). The two regions were chosen for the contrasted use of the dairy sheep breeds raised there. The Corsican breed is the main sheep breed in Corsica, whereas a variety of local and exotic breeds coexist in Thessaly in purebred and crossbred flocks.
breeds such as the Lacaune, Assaf and Awassi breeds. The Karagouniko breed, the main local breed in the region is raised on semi-extensive lowland farms. The breed is tall (58–68 cm shoulder height and 45–60 kg LW in females), with a white fleece and black spots on the head and feet with black and white variants (Hatziminaoglou, 2001). This dairy breed has a prolificacy of 1.45 (FAO, 2018) and its average annual milk yield in 2014 was 165 L/ewe for 133 milking days (data from KGBZ). The Chios breed is a dairy breed raised on more intensive farms in Thessaly (Gelasakis et al., 2010) and is tall (an average of 73 cm wither height and 60 kg LW for females), with a white fleece spotted with black areas on the head, belly and feet, high prolificacy (1.9) and high productivity (Hatziminaoglou, 2001; FAO, 2018). Finally, other local breeds in Thessaly are small population breeds, including Kalarritiko (with the largest number of transhumant flocks), and Piliou and Skopelos, making up only a few flocks restricted to certain locations.
2.3. Sampling and data collection A survey of 81 dairy sheep farms was conducted between 2014 and 2016 in Corsica (n = 39) and Thessaly (n = 42). We did not aim to get a representative sample of the farmer population but to maximize the diversity of farming systems likely to influence farmers' preferences for breeds and animal traits. The sample was obtained through non-probability sampling in two steps. For the first round of the survey, a small number of farms (n = 26 in Corsica and n = 23 in Thessaly) was identified based on the previous characterization of regional production systems completed by regional databases and information from professionals in the sector. The criteria for this first sampling of farms in Corsica and Thessaly were flock size, type of grazing areas and cultivated areas, practice of transhumance, milking method, geographical location and participation in a breeding scheme. Other criteria for the sampling were also used in the first round of the survey depending on the data available, or if they made specific sense in the region (i.e. onfarm cheese processing in Corsica, flocks in a breed conservation programme in Thessaly). The first round was then completed by snowball sampling (n = 13 in Corsica and n = 19 in Thessaly), which is a “nonprobability method of survey sample selection that […] relies on referrals from initially sampled respondents to other persons believed to have the characteristic of interest.” (Johnson, 2014). For this purpose, farmers in the first round were asked for contacts who fulfilled the criteria for sampling not adequately covered in the first round. Data were collected by the same operator in face-to-face semistructured interviews with farmers. The average duration of an interview was two hours. The farmers’ responses were recorded by notes taken by the operator throughout the interview. The interview consisted of a general part concerning the characterization of the farm and a second part focusing on understanding the farmers’ breeding practices. In the second part, farmers were asked how they choose males and females for replacement and culling. Moreover, farmers were interviewed about the adoption of their particular breed flock
2. Material and methods 2.1. Study areas Dairy sheep farming in Corsica and Thessaly highly contributes to the economic outputs of the regional livestock activity, through the production of PDO cheeses or whey-cheese and several local cheeses. In Corsica, about a third of the sheep milk produced is processed on-farm (DRAAF Corse, 2017), while on-farm cheese processing for commercial purposes is seldom practiced in Thessaly. The situation of the genetic resources at the regional level is different in each region, as it is the case for calendar(s) of milk collection at the farm scale. Milking methods are diverse in both regions. Finally, in both regions, dairy sheep farming includes the use of native grazing lands under a Mediterranean climate and the use of transhumance in a minority of farms. In such pastoral farming conditions, the capacity for adaptation and the hardiness of the animals are likely to rank among farmers’ preferences. These main farming conditions are presented in Table 1. 2.2. Description of main local breeds The Corsican breed ewe is a small dairy breed of the island of Corsica (an average of 55 cm wither height and 35 kg LW for females) with coarse wool, horns and multi-variant fleece colours (FAO, 2018). The breed is considered as rustic, well-adapted to extensive farming thanks to its walking ability, has low prolificacy (1.15, AgroParisTech, 2007), high fat and proteins content in milk (7.1% fat and 5.57% protein in 2014) and an average annual milk yield of 162 L/ ewe for 185 milking days in 2016 (data from OS Brebis Corse). In Thessaly, several local breeds and local populations coexist with exotic Table 1 Context and characteristics of dairy sheep farming in Corsica and Thessaly. Corsica
Thessaly
Breed composition Breeding scheme
Corsican breed ewe Regional breeding scheme
Milking methods Main production calendar Climate Vegetation of main grazing lands Topography Transhumance
Hand and machine milking Autumn lambing and milk production until summer Mediterranean Scrublands Combination of lowlands, hilly and mountain ranges Yes (minority of farms) Short and medium distance
Purebred and crossbred flocks Indigenous and exotic breeds Regional breeding scheme Hand and machine milking Different lambing seasons and periods of production Mediterranean Scrublands and grasslands Combination of lowlands, hilly and mountain ranges Yes (minority of farms) Short to long distance
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composition (Thessaly) and about the providers of breeding animals (Thessaly and Corsica). Information on the content of the interview grid is available in Online Resources 1 and 2.
Table 2 TOIs identified in Corsica and Thessaly. Traits of interest (TOIs)
Dairy and meat yield Milk yield Milk persistence Longevity Milk quality Meat yield Meat quality Feed intake Ability to feed Feed conversion Reproduction Suckling ability Prolificacy Deseasoning Development of male sexual organs Fertility Ability to mate Maternal behaviour Ability to lamb successfully Autonomy in lambing Adaptation to biophysical constraints Sensitivitya to mastitis Resistance to scrapie Sensitivitya to other/undefined diseases Udder depth at grazing Ability to cope with transhumance Feeding behaviour Sensitivitya to cold and humidity Sensitivitya to heat Adult hardiness Adaptation to feed restriction Walking ability Feed conversion on pastures Ability to milk rebound in spring Ability to maintain body condition Work management Ease of milking Behaviour with humans Behaviour with respect to shepherding Conformation and aesthetics Adult breed standard and aesthetics Lamb breed standard and aesthetics Adult conformation Lamb conformation Horn orientation Udder abnormalities Udder conformation (others)
2.4. Data analysis Three steps of data analysis enabled us to identify the range of TOIs and their farmers’ management processes in Corsica and Thessaly. First, TOIs were identified from the farmers’ responses and named with a generic formulation inspired by usual terms of the literature in order to facilitate comparison of their distribution between fields. Traits mentioned by farmers were considered as TOIs if they matched one or both of the following definitions: (i) a trait motivating a current on-farm practice (ii) a trait playing a role in the adoption or rejection of an alternative on-farm practice. These traits could concern individual animals, the whole flock or a specific breed or crossbreed. By on-farm practices, we mean all practices linked with the management of the flock: breeding practices, feeding, housing, batching, etc. In breeding practices, we include breed(s) choice, internal replacement (for males and for females), culling, and breeding animals purchase. The aim of using the above definition of TOI, assuming false negatives, was to ensure that all animal traits subsequently included in the analysis were indeed of interest to the farmers themselves. The objective of the second step was to assess the extent to which the TOIs were exclusively or partially used as internal replacement criteria. Internal replacement criteria are defined here as TOIs used for the choice of an ewe's offspring as a future breeding animal in the flock. The term «criteria» was chosen to emphasize the fact that replacement is a selection process aimed at transmitting the TOI to the future breeding animals. Motives of culling can cover a variety of reasons that are more difficult to distinguish: to manage on-going performance of the flock and/or to avoid transmitting these traits to the future breeding animals of the flock. Following the above-mentioned definition of TOIs, motives of culling have been translated in TOIs regardless of the reason underlying culling. For each TOI we listed: (i) the number of farms in which this TOI was used as an internal replacement criterion (ii) the set of alternative or complementary breeding practices taken into consideration by the interviewed farmers for the management of their flock performance (i.e. culling, choice of the breeds or crossbreed, use of specific sub-populations of ewes and rams purchase). Finally, the last step consisted in identifying the correlations between TOIs and the use of these correlations through the previously identified breeding practices. Correlations between TOIs were defined from farmers’ perception, i.e. as the use of a TOI as an indicator to improve another TOI.
Corsica (% of farmers)
Thessaly (% of farmers)
100 74 23 18 0 0 0 0 3
100 81 21 26 19 7 33 5 2
38 23 23 10 10 5 3 0 3
7 21 5 2 24 2 5 5 5
49 21 59 33 23 23 15 0 13 8 5 8 8 23
45 0 69 0 14 14 50 45 48 7 12 10 7 17
74 44 0
33 14 26
49 13 15 31 28 31 79
45 45 24 71 0 0 60
a In order to simplify the presentation of results, sensitivity was used as a generic term. This trait designation could mean either “affected by” or “sensitive to” (stricto sensu)
3. Results
3.2. Management of flock performance for TOIs: Diversity of levers
3.1. Traits of interest
Different levers were used by farmers to manage the performance of the flock for each TOI. These levers differed depending on the TOI and the region concerned (Table 3). Selecting males and females for internal replacement was a main lever to manage flock performance for milk yield, milk persistence, suckling ability, udder depth at grazing, ease of milking, breed standard and aesthetics (lamb and adult), lamb conformation, udder conformation and udder abnormalities. In addition, farmers could manage the flock performance for these TOIs through other breeding practices: purchase of external breeding animals on breed standard and aesthetics, culling of females on productive or udder traits, etc. On the contrary, in both regions, some TOIs were scarcely managed through internal replacement and rather managed through the choice of the breed(s), the choice of specific providers or sub-populations of ewes for the purchase of breeding animals and/or the culling of animals on their corresponding phenotypes. This is the case of milk quality and
The TOIs identified in each region and the percentage of farmers concerned are listed in Table 2. In both regions, milk yield, milk persistence, udder conformation and sensitivity to diseases were considered by more than 50% of the interviewed farmers. Adult breed standard and aesthetics, lamb conformation and ease of milking were also frequent TOIs in both regions (30–50% of the interviewed farmers), as were longevity and prolificacy to a lesser extent (20–30% of the interviewed farmers). Other TOIs were specifically important (>30% of the interviewed farmers) in Thessaly (sensitivity to climate, adult hardiness, feed intake and lamb breed standards and aesthetics) or in Corsica (behaviour with humans, udder depth at grazing, udder abnormalities as cysts and supernumerary teats).
160
23 5 – 33
23 5 –
10
23 18 –
38
23 23 10
Longevity Milk quality Feed intake Reproduction Suckling ability
Prolificacy Deseasoning Fertility
Adaptation to biophysical constraints Sensitivity to mastitis 49
161 5 – 5 3 69
33 23
23
15
– 13
23
74
44
49
13 15
Udder depth at grazing Ability to cope with transhumance
Feeding behaviour
Sensitivity to cold and humidity
Sensitivity to heat Adult hardiness
Ability to maintain body condition Work management Ease of milking
Behaviour with humans
Conformation and aesthetics Adult breed standard and aesthetics
Lamb breed standard and aesthetics Adult conformation
13 7
26
33
5
28 –
59
Sensitivity to other/undefined diseases
3
45
74
Milk persistence
92
Internal replacement criterion (% of farmers)
100
Corsica TOI (% of farmers)
Dairy and meat yield Milk yield
Trait
Motive for choosing external rams or rams providers Subpopulations of Corsican ewes or breed Motive for choosing external rams Subpopulations of Corsican ewes or breed Motive for choosing external rams
Motive for female culling Motive for choosing external rams or rams providers Subpopulations of Corsican ewes or breed Motive for female and male culling Motive for choosing rams providers
Motive for female and male culling Motive for choosing rams providers Subpopulations of Corsican ewes or breed Motive for female culling Motive for choosing rams providers Motive for female culling Subpopulations of Corsican ewes or breed Motive for choosing rams providers Motive for female culling Subpopulations of Corsican ewes or breed None Motive for choosing external rams or rams providers Motive for male culling
Motive for female culling
Motive for female and male culling Subpopulations of Corsican ewes or breed Motive for choosing rams providers Motive for choosing external rams None Motive for female culling
Motive for female culling Motive for choosing external rams or rams providers Subpopulations of Corsican ewes or breed None Subpopulations of Corsican ewes or breed None
Motive for female culling Motive for choosing external rams or rams providers
Other breeding practices used to manage flock performance for the TOI
Table 3 Management of flock performance for specific TOIs and the respective breeding practices applied by farmers.
Breed Motive for female culling Breed
–
7
14
45 24
45 –
21
21
33
45
Breed
– 17
(continued on next page)
None Motive for choosing external ram Breed
Motive for choosing external ram Breed (for aesthetics)
Breed Motive for female culling
Breed Motive for male culling
Breed Breed
– – 45 48
50
5
– –
– 14 14
–
Breed Motive for female culling Breed Motive for female culling Motive for choosing rams providers None Breed
Breed Breed Breed Motive for female culling
None
Breed Breed Breed
Breed Motive for male and female culling Motive for choosing external rams or ram providers Breed Motive for female culling
Other breeding practices used to manage flock performance for the TOI
2
69
45
5 – –
2
7
21 5 24
5 – –
45
81
21 26 33
95
Internal replacement criterion (% of farmers)
100
Thessaly TOI (% of farmers)
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18 31 Udder abnormalities
feed intake (mainly through the breed lever), reproductive traits as fertility (mainly through culling) and deseasoning (mainly through flock management in Corsica and through the breed lever in Thessaly), and the majority of TOIs associated with the adaptation to biophysical constraints (several levers). In general, external purchase of breeding animals was driven by the following farmers’ rationale: in both regions, the choice of ram providers was based on confidence and geographical proximity; it aimed at limiting the risk of introducing diseases or breeding animals with low dairy potential in the flock. Moreover, in Corsica, farmers distinguished sub-populations of the Corsican breed according to their location. They associated these locations to different biophysical environments or to possible crossbreeding with the Sardinian breed. The use of breeding animals from such locations was then used to manage flock performances for TOIs linked to adaptation to the biophysical environment and to the Corsican breed or some of its subpopulations (e.g. ease of milking and suckling ability, breed standard and aesthetics). Finally, regarding trait management, the role played by the choice of the breed(s) with respect to the role of internal replacement could differ between regions. For example, internal replacement was often used in Corsica to manage the flock performance for longevity, prolificacy and behaviour with humans, whereas in Thessaly, farmers rather used the breed lever to manage these TOIs.
Results are presented for TOIs considered by at least 23% of the sampled farmers in a region (n = 9 farmers in Corsica, n = 10 farmers in Thessaly).
None – –
Breed Motive for female culling 40 60 79 Udder conformation
69
28 Horn orientation
18
Motive for male culling Motive for choosing external rams Motive for female culling Motive for choosing rams providers Subpopulations of Corsican ewes or breed Motive for female and male culling Motive for choosing rams providers
–
–
Breed Motive for male culling None 55 31 Lamb conformation
15
Motive for female culling
71
Other breeding practices used to manage flock performance for the TOI Corsica TOI (% of farmers) Trait
Table 3 (continued)
Internal replacement criterion (% of farmers)
Other breeding practices used to manage flock performance for the TOI
Thessaly TOI (% of farmers)
Internal replacement criterion (% of farmers)
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3.3. Management of the flock performance for a TOI: Role of correlations between TOIs as perceived by farmers Among the breeding practices used to improve flock performance for a given TOI, below we refer those resulting from farmers’ perception of correlations between TOIs. These practices consisted in using an easily assessable TOI as a criterion of replacement, a motive for culling or a motive for choosing a breed, in order to improve flock performance with respect to its positively correlated TOI (Table 4). In these cases, the easily assessable TOI was a morphological TOI (lamb conformation, udder conformation, breed standard and aesthetics) or milk yield. The indirectly considered correlated TOI was then either milk yield or a TOI linked to adaptation to biophysical constraints (sensitivity to mastitis, hardiness, sensitivity to cold). A negative correlation between TOIs, as perceived by farmers, concerned sensitivity to mastitis and milk yield, and milk persistence and milk yield at peak lactation. These TOIs were used as replacement criteria: mitigating the level of selection on milk yield indirectly enabled improvement of flock performance for milk persistence and aimed at decreasing sensitivity to mastitis. 4. Discussion 4.1. An insight on farmers’ strategies Farmers used different breeding practices for the management of flock performance for different traits, according to the region and the TOIs considered. The use of one or several of these breeding practices can be understood as different farmers’ ways to deal with the complexity (or scarcity) of tools and information available for the management of their flock performance (Martin-Collado et al, 2018). For example, Thessaly hosts several exotic and indigenous breeds known or tested on-farm for their different morphological and physiological characteristics, among which longevity, prolificacy and behaviour with humans. A simplified way used by farmers to manage these TOIs in the flock was to change the breed and focus internal replacement on other TOIs. On the contrary, in Corsica, internal replacement was used by farmers to maintain these TOIs in their local purebred flocks. Likewise, farmers’ rationale for the purchase of breeding animals (confidence, location) and the use of correlation between TOIs were simplified strategies to manage flock performance for TOIs difficult to assess (e.g. ascendants’ TOIs of a ram purchased from another farm or animal hardiness). These strategies refer to the competence-difficulty gap 162
Replacement and/or culling based on udder conformation (teats, shape, size, depth) enables selection of animals based on ease of milking Choice of the breed based on udder conformation (teats, shape, depth) indirectly enables the choice of breeds easy to milk Replacement and/or culling based on udder size and/or udder shape enables selection of animals based on milk yield
Replacement and/or culling based on udder conformation (teats, depth) enables selection of animals based on suckling ability Choice of the breed based on udder conformation (teats) indirectly enables the choice of breeds with suckling ability Replacement and/or culling based on milk persistence indirectly manages flock performance with respect to sensitivity to cold Choice of the breed based on milk persistence during cold weather indirectly enables the choice of breeds with low sensitivity to cold Replacement and/or culling based on milk yield to indirectly manage flock performance for milk persistence (positive or negative correlations between the two TOIs) Replacement on milk persistence indirectly enables selection of animals based on milk yield Replacement based on thin morphology or "beautiful appearance” indirectly enables selection of animals based on milk yield Replacement based on similar morphology with ascendants indirectly enables selection of animals based on ascendant TOI including milk yield Replacement based on lamb conformation indirectly enables selection of animals based on milk yield
Ease of milkinga Udder conformation
Suckling abilitya Udder conformation
163
Replacement of external rams based on adult morphology referring to populations in central Corsica indirectly enables management of flock performance for adult hardiness Replacement based on fleece colour or breed standard referring to rustic breeds indirectly enables selection of animals based on hardiness
Adult hardiness Adult breed standard and aesthetics
Variable correlations with lamb weight and depending of breeds, litter size, and moment between birth and weaning (e.g. Slen et al., 1963; Burgos-Gonzalez et al., 2018) Variable or negligible genetic correlations with somatic cell counts/scores, depending (among other factors) on lactation stage and breed (Bergonier et al., 2003; Salaris et al., 2012; Barillet et al., 2001) Adaptation to thermal stress are linked with coat colour (through coat reflectance, Mc Manus et al, 2011), fat deposit on tails and rump, smaller ears and legs (Mirkena et al., 2010)
Variable or non-significant correlations for several body traits (e.g. Perez-Cabal et al., 2013; de la Fuente et al, 2011)
Link with milk persistence depends on the moment milk yield is assessed (total milk yield, lactation peak, t-time during lactation) (Kominakis et al., 2002; Wood equation)
Positive correlation for udder dimensions, negative or positive correlation between teat angle, teat position, teat placement (e.g. Mavrogenis et al., 1988; Labussière et al., 1981; Dzidic et al., 2004; Legarra and Ugarte, 2005; Iniguez et al., 2009) Significant link between udder type and milk suckled only at specific lactation stages (Unal et al., 2007) Significant link between low lamb weight and sub-optimal teat position (Huntley et al., 2012) Significant link between low temperatures, humidity and milk yield or milk production decay (e.g. Peana et al., 2017; Ramon et al, 2016)
Positive correlation for udder width, udder surface areas, teat position (e.g. Labussière et al., 1981; Dzidic et al., 2004)
Examples of correlations found in literature for sheep
Results are presented for correlations used at least by 3 farmers across study areas to improve flock management for a given TOI. a Replacement and/or culling based on udder depth and/or teat position enables joint selection of animals based on ease of milking and suckling ability (n = 3 farms)
Mitigating replacement based on milk yield indirectly enables selection of animals based on low sensitivity to mastitis (negative correlation)
Sensitivity to mastitis Milk yield
Milk yield Lamb conformation
Milk yield Milk persistence Milk yield Adult breed standard and aesthetics
Milk persistence Milk yield
Sensitivity to cold Milk persistence
Milk yield Udder conformation
Farmer rationale
TOI to improve TOI used as indicator
Table 4 Use of correlations between TOIs for the management of TOIs across regions.
2
8
2
7
5
5
5
7
10
13
7
13
2
21
26
31
31
Thessaly (% of farmers)
46
Corsica (% of farmers)
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4.3. Conclusion
(farmers’ knowledge of correlation between traits, farmers’ knowledge of breed traits), to recognition heuristics and one-reason decision making (basing ram purchase on the trust in the provider or on the biophysical environment of the providing farm), and social heuristics (imitating other farmers behaviour or following their knowledge of the breed) (Martin-Collado et al, 2018). Comparison between farmers’ perception of correlations between TOIs and examples of correlations found in literature (Table 4) indicated that farmers have a good knowledge on traits correlated with udder conformation (ease of milking, milk yield, suckling ability) but at some extent, the use of correlated traits might not reach its aim due to the complexity of correlations (improvement of sensitivity to mastitis through milk yield, of milk persistence through milk yield, of milk yield through lamb conformation).
Dairy sheep farmers in Corsica and Thessaly used several levers to guide the performance of their flock towards the different TOIs considered. TOIs were not automatically used as internal replacement criteria, but their expression in the flock could be achieved through other breeding practices such as the choice of the breed(s) composing the flock or the use of specific networks of ram providers. In particular, these two breeding practices were preferred for the management of flock performance for TOIs linked with the adaptation to the biophysical constraints. The breed lever could also replace the internal replacement lever when several breeds displaying contrasted phenotypes were available in the region. Finally, correlations between TOIs (as perceived by farmers) contributed to the use of these different levers to improve flock performance towards the desired way. The knowledge of the different breeding practices used by farmers to improve flock performance for TOIs will help to orientate breeding schemes towards TOIs used to be managed through the breed lever. It will also contribute in proposing adequate indicators to farmers for the selection of their internal breeding animals, according to the TOI they wish to improve. Finally, the diversity of TOI targeted by farmers through their on-farm breeding practices can be further used as a basis of discussion for participatory approaches aiming at defining common breeding objectives.
4.2. Analysing breeding practices used by farmers to manage flock performance for a TOI The comprehensive approach of farmers’ decision making processes indicated that not necessarily each TOI identified was used by the farmers as an internal replacement criterion. A stated-preference approach of farmers’ preferences could permit to complete this result by a first systematic checking of farmers’ preferences for a predefined list of TOIs (e.g. Ahlman et al., 2014) and, second, by the discussion of their potential use as internal replacement criteria. In these two steps, the current level of flock performance for a trait (Slagboom et al., 2016), the range of available selection criteria to the farmer (as suggested in Ndumu et al., (2008) through perceived values of animals), the farmers’ perception of TOIs heritability, correlations and the trade-offs performed between them (Haile et al., 2013; Bett et al., 2009) should be considered as factors influencing the use of specific internal replacement criteria. In the literature, the role of the breed is tackled through: (i) the breed(s) composing the breeding stock (as a variable illustrating farmers’ preferences for TOIs and selection criteria, e.g. Bebe et al., 2003; Martin-Collado et al., 2015; Tabbaa et al., 2009) (ii) farmers’ preferences for breeds (e.g. Nauta et al., 2009; Zander and Drucker, 2008) or for breed traits (e.g. Jabbar and Diedhiou, 2003; Mwacharo and Drucker, 2005; Wurzinger et al., 2006) (iii) the ranking of predefined traits assumed to define the breed (e.g. Bebe et al., 2003; Zander and Drucker, 2008; Zonabend Konig et al., 2015) (iv) the breed listed as a TOI or as a selection criterion (e.g. Dossa et al., 2015; Ragkos and Abas, 2015). In Corsica and Thessaly, the breed played a key role in the farmers’ decision making process for the improvement of their flock (a) through the use of the breed for crossbreeding or as a purebred flock (b) through selection based on breed standard as a replacement criterion (c) through the restriction of external supply in breeding animals to specific animal sub-populations within the breed. Consequently, analyzing the role of the breed in the improvement of flock performance would need to include the animal populations targeted through the choice of rams’ providers, and the reasons for replacing or culling animals based on the breed standard. External replacement through market transactions is often taken into account in studies of farmers preferences for TOIs (e.g. Scarpa et al., 2003; Tindano et al., 2017). Modalities of external replacement can include for example the attributes of the buyer and seller (Jabbar and Diedhiou, 2003) or the advice from providers and the prestige of the provider (Martin-Collado et al., 2015). Our results suggest that these modalities should be further investigated as simplified strategies to select breeding animals with one or several TOIs. Finally, when culling practices are investigated (e.g. Kugonza et al., 2011; Bett et al., 2009), it would be interesting to systematically specify with farmers whether or not their motives of culling aim solely at managing the on-going flock performance for a TOI or are part of a conscious strategy to avoid transmitting faulty traits to the next generation of breeding animals.
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