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Regrouping in lactating goats increases aggression and decreases milk production
Small Ruminant Research 70 (2007) 228–232
Regrouping in lactating goats increases aggression and decreases milk production M.A. Fern´andez a , L. Alvarez a,b,∗ , L. Zarco a a
Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Aut´onoma de M´exico, Ciudad Universitaria, Ciudad de M´exico 04510, Mexico b Centro de Ense˜ nanza Pr´actica e Investigaci´on en Producci´on y Salud Animal, Cruz Blanca 486, San Miguel Topilejo, Tlalpan, Ciudad de M´exico 14500, Mexico Received 14 March 2006; received in revised form 14 March 2006; accepted 22 March 2006 Available online 19 May 2006
Abstract With the aim of testing the hypothesis that regrouping decreases milk production in French Alpine goats that were lactating, a study was done using two groups (n = 8, 7). During their third month after parturition, four goats from each group were exchanged (first regrouping) between pens and left for 2 weeks, then the same two subgroups of four goats were taken back to their original pen for another 2 weeks (second regrouping). In the third regrouping, the two groups were all placed in the one pen. Milk production and social behaviour were measured daily before and after each regrouping. All regroupings led to an increase in aggressive behaviours that last by 1–2 days. Mean daily milk production decreased after first (2.82 ± 0.2 kg versus 2.53 ± 0.2 kg; P < 0.05) but not after second and third regrouping. It is concluded that aggressive behaviour increases after all regroupings, whereas milk production decreases only after the first regrouping, suggesting an important capacity of adaptation to a novel and stressful managements in the French Alpine goat. The study highlights the importance of considering effects of common practices in herd managements on social behaviour and production. © 2006 Elsevier B.V. All rights reserved. Keywords: Regrouping; Social behaviour; Goat; Social dominance; Milk production
1. Introduction In modern and high-producing dairy herds, regrouping according to age, nutrient requirements, body condition, lactation period and level of milk yield, is a common practice of management to enhance productivity and profitability. Mixing unfamiliar animals is also common in fattening animals. However, as a result of the vigorous fighting associated with the establishment of a
∗ Corresponding author. Tel.: +52 55 58 48 05 15; fax: +52 55 58 48 05 14. E-mail address: [email protected] (L. Alvarez).
0921-4488/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.smallrumres.2006.03.008
new social hierarchy, the practice may temporally disturb social structure of the herd, which may distress animals and have adverse effects on milk production (Bøe and Færevik, 2003). In heifers (Hasegawa et al., 1997), social structure is affected by regrouping, provoking an increase in aggressive behaviour and a decrease in milk production, specially in the subordinate animals. Goat is a very hierarchical species, with a very clear structure of dominance and an almost linear social hierarchy (Addison and Baker, 1982; Barroso et al., 2000; Alvarez, 2004). In feral herds of this species (Alley and F´ordham, 1994), introduction of new members to an established group leads to a significant increase in
M.A. Fern´andez et al. / Small Ruminant Research 70 (2007) 228–232
aggression, temporally disrupting social structure and interfering with normal activities as feeding. Disruption of social organization in French Alpine goats as a consequence of regrouping might also negatively affect milk production. This study was done to test the hypothesis that introduction of new members to an established group of French Alpine goats leads to an increase in aggression and a decrease in milk production. 2. Materials and methods The study was carried out on an experimental intensive farm located close to Mexico City (2760 m above sea level, 19◦ 13 N, 99◦ 8 W) using a protocol that had been approved by the Internal Animal Ethics Committee of the Faculty of Veterinary Medicine and Zootechnie. Two groups (n = 8, 7) of lactating French Alpine goats, 28.0 ± 2.64 months old were used; all goats were in their first (11 does) and second (four does) lactation. Groups of same average age (30.7 ± 4.08 and 24.8 ± 3.2 months) were formed at the moment of parturition, and remained in different 160 m2 pens separated by 20 m. During their whole pregnancy time, goats were all together in the same pen until the day of parturition. Milk production per week was measured from day 5 after parturition in all goats (except during the regroupings period). Three months after parturition, four goats of similar age from each group were selected randomly and exchanged (first regrouping) between pens and left for 2 weeks, then the same two subgroups of four goats were taken back to their original pen for another 2 weeks (second regrouping). In the third regrouping, the 15 goats of both groups were all placed in the one pen. From 2 weeks before the first regrouping and until 2 weeks after the third, milk production was measured daily. At the same time, the behaviour of the goats was studied for 4 h/day to determine the levels of aggression. The behaviours recorded were: butts, when the goat used the front of her head to make contact with another goat; chases, when a goat actively moved towards another individual, causing the latter to walk or run away; threats, when a goat turned towards or approaches another individual with head down and then lunges without making contact; displacements, when a goat actively moved away from another individual whether or not previous interaction has occurred between the two individuals; and bites, when the goat used her mouth and tooth to attack another individual, as described by Alvarez et al. (2003); the initiator, winner and loser of each interaction were recorded and the end of an interaction was recorded when one of the animals involved withdrew or displaced; this information was used both, to determine the changes in the
229
aggression activity, and also to calculate an individual index of success (IS) in agonistic interactions and to create three ranking (high, medium and low) groups using the procedure described by Alvarez et al. (2003). Briefly, index of success was calculated using the formula: IS =
Number of goats that an individual displaces (Number of goats that an individual displaces + Number of goats that displace the individual)
High ranking goats were those whose SI was from 1.0 to 0.667, IS of medium ranking goats was from 0.666 to 0.334, and IS of low ranking goats was from 0.333 to 0.0. In addition, the number of times each goat visited the feeder was also recorded during these observations, using scan sampling (every 5 min). All goats were weighed every week. The goats were fed with a silage-based diet with oat and concentrate three times per day, at 08:00, 12:00 and 15:00 h (meeting the requirements of the National Research Council, 1985). Feed was provided in a 9 m long feeder, and water was provided ad libitum. 2.1. Data analysis Data were analyzed using t-test for related samples, analysis of variance and Duncan’s test. Behavioural information was analyzed using Kruskall–Wallis and Mann–Whitney tests. All the analysis was done using the Statistica software of StatSoft© (StatSoft, 1998). Means are ±standard error. 3. Results Frequency of registered aggressive behaviours were notably increased during all regroupings, especially during regroupings one and three (Fig. 1). Aggression was higher during the day of regrouping and tended to decrease to pre-regrouping levels the day after regrouping (Fig. 1). Mean daily milk production decreased after first regrouping (P < 0.05; Table 1). The mean decrease in milk production was of 10% in the week after regrouping compared with the week before (Table 2). There were not significant changes in daily milk production after second and third regroupings (Table 1). At the end of the experiment, three goats were classified as high, seven as medium and five as low rank. Most goats had consistently the same IS and rank position during regroupings, only two goats changed their position from low to medium and from medium to low rank, respectively. Daily milk production (kg ± S.E.)
230
M.A. Fern´andez et al. / Small Ruminant Research 70 (2007) 228–232
4. Discussion
Fig. 1. Frequency (events/h) of the recorded behaviours (bites, threats, butts and displacements) before and after each regrouping. Note the different scale in Y-axis of the third graphic.
was higher in goats of medium rank (2.99 ± 0.26) than in goats of high rank (2.03 ± 0.42; P = 0.06) and similar to goats of low rank (2.31 ± 0.24). Total milk production during the complete experiment was also higher in medium rank goats (212.5 ± 19.0) than in high rank goats (144.48 ± 30; P = 0.06). Frequency of visits to the feeder did not differ between the high, medium and low ranking group (2.5 ± 0.1, 3.2 ± 0.3 and 2.9 ± 0.4, respectively).
Table 1 Daily milk production (mean, kg ± S.E.) during 1 week before and 1 week after each regrouping of the 15 French Alpine goats Regrouping
Week before
Week after
First Second Third
2.82 ± 0.22 a 2.47 ± 0.19 a 2.43 ± 0.20 a
2.53 ± 0.21 b 2.47 ± 0.17 a 2.41 ± 0.18 a
a, b different letters between columns indicate significance (P < 0.05).
As expected, regrouping of the French Alpine goats led to an increase in aggressive interactions, suggesting a temporal disruption of the social structure of the herd. This is in agreement with what Addison and Baker (1982) found in feral goats. In all cases, 3 days after regrouping aggression implying physical contact was in the same level as before mixing the animals, which indicates that in the used size of groups, 3 days was time enough for the social organization to be reestablished. Changes in social behaviour after regrouping followed what Kondo and Hurnik (1990) predicted for cattle, with the ratio of physical to non-physical interactions remaining comparatively stable. It is well accepted that increased aggression after regrouping is a stressful situation for animals, and the negative effects of regrouping have been tough to be caused by the stress hormones, aimed ACTH and cortisol. A decrease in milk production has been reported in cows when ACTH or corticoids are elevated or injected (Varner and Johnson, 1983; Shamay et al., 2000a), however, same treatments in goats have shown inconsistent results, increasing (Stewart and Thompson, 1984) or having no effects (Anderson et al., 1991; Shamay et al., 2000b) on milk yield. The formerly two mentioned studies did not use a social environment disturbed by aggression, were the effect of the stress hormones could probably be more intense. During the time the social structure of the group is being reestablished after regrouping, increased aggression could also affect feeding, decreasing the amount of food that some goats consume. Thus, decrease in daily milk production after first regrouping might be a consequence not only of the augmented aggression, but also of the social stress and differences in food consumption during that time. In deciding whether an animal is affected or not by the social perturbation, social dominance before regrouping seems to be important. Similar findings suggesting the relevance of social dominance have been published by Hasegawa et al. (1997) in heifers, with the dominant individuals being the less affected. No effects on milk production after the second/third regroupings might indicate an important capacity of adaptation to a novel and stressful repeated management in these goats. In that regard, time between each regrouping could also be important, as it probably was not long enough to make the animals unfamiliar. Although it has been said that goats are better adapted to harsh environmental conditions than other domesticated ruminants and that this is reflected in attenuated response to stressful conditions (Silanikove, 2000), other ruminants have
M.A. Fern´andez et al. / Small Ruminant Research 70 (2007) 228–232
231
Table 2 Daily milk production (mean, kg ± S.E.) and its changes during the week before (week −1) and after (week 1) the three regroupings in goats according with their social dominance and whether they remained or were moved from their original pen Week −1 (kg) First regrouping High dominance, remained (3) Medium dominance, remained (3) Low dominance, remained (1) All (7) Medium dominance, moved (4) Low dominance, moved (4) All (8) Second regrouping High dominance, remained (3) Medium dominance, remained (3) Low dominance, remained (1) All (7) Medium dominance, moved (4) Low dominance, moved (4) All (8) Third regrouping High dominance (3) Medium dominance (7) Low dominance (5) All (15)
Week −1 (%)
Week 1 (kg)
0.13 0.24 0.25 0.16
100 100 100 100
1.88 3.18 1.24 2.1
0.12 0.21 0.07 0.14
87.96 91.11 79.13 87.56
−12.04 −8.89 −20.87 −12.44
3.23 ± 0.08 2.74 ± 0.08 2.98 ± 0.07
100 100 100
2.87 ± 0.06 2.52 ± 0.07 2.69 ± 0.05
88.96 91.99 90.35
−11.04 −8.01 −9.65
± ± ± ±
0.13 0.18 0.06 0.13
100 100 100 100
2.06 3.08 1.41 2.18
± ± ± ±
0.14 0.14 0.02 0.12
101.44 96.03 94.75 97.38
+ 1.44 −3.97 −5.25 −2.62
2.69 ± 0.07 2.29 ± 0.11 2.49 ± 0.07
100 100 100
2.72 ± 0.04 2.37 ± 0.07 2.55 ± 0.05
101.03 103.68 102.25
+1.03 +3.68 +2.25
± ± ± ±
100 100 100 100
1.96 2.77 1.96 2.23
± ± ± ±
103.57 97.76 103.33 101.02
+3.57 −2.24 +3.33 +1.02
2.14 3.49 1.57 2.40
2.03 3.21 1.49 2.24
1.89 2.83 1.89 2.20
± ± ± ±
0.13 0.19 0.03 0.13
± ± ± ±
0.14 0.21 0.14 0.13
Week 1 (%)
Change (%)
Week −1: week before regroupings. Week 1: week after regroupings. Data in parenthesis indicates number of goats.
also shown a good capacity for habituation to regrouping (calves, Veissier et al., 2001), and lactating ewes show only short term effects on production performance when under the same management (Sevi et al., 2001). Goats differed in their milk production according to their social position. Unexpectedly, goats that were in medium rank produced more than high-ranking does. In Spanish breed goats (Malague˜na, Serrana, Granadina), does of intermediate rank are also the most productive (Barroso et al., 2000). There is not a very clear explanation for such a difference in milk production, Barroso et al. (2000) have proposed that middle-ranking goats could suffer from less social pressure than the animals of inferior status and, at the same time not have to expend energy in continual aggression to maintain their position as with the most dominant animals. In this possible “social strategy” for not to spend too many energy, which is observable in a better productive performance, a clear and identifiable behavioural pattern could be being displayed, it is interesting that this social strategy might be selected to improve the herd productivity. Similar selection has been done according to temperament in sheep, achieving successful results in improving lamb’s viability and female’s sexual behaviour (Gelez et al., 2003).
It is concluded that aggressive behaviour increases after all regroupings, whereas milk production decreases only after the first regrouping, suggesting an important capacity of adaptation to a novel and stressful managements in the French Alpine goat. The study highlights the importance of considering effects of common practices in herd managements on social behaviour and production. Acknowledgements The study was partially supported by Consejo Nacional de Ciencia y Tecnolog´ıa (CONACYT, grant 34924-B) and Programa de Becas para Tesis de Licenciatura (PROBETEL, grant for Adri´an Fern´andez). References Addison, W.E., Baker, E., 1982. Agonistic behavior and social organization in a herd of goats as affected by the introduction of non-members. Appl. Anim. Ethol. 8, 527–535. Alley, J.C., F´ordham, R.A., 1994. Social events following the introduction of unfamiliar does to a captive feral goat (Capra hircus L.) herd. Small Rumin. Res. 13, 103–107. Alvarez, L., 2004. Efecto de la dominancia social sobre la efectividad de la inducci´on de actividad ov´arica en cabras an´estricas medi-
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ante bioestimulaci´on sexual con machos o con hembras en estro (Tesis de doctorado). M´exico, D.F., M´exico: Facultad de Medicina Veterinaria y Zootecnia, UNAM. Alvarez, L., Martin, G.B., Galindo, F., Zarco, L.A., 2003. Social dominance of female goats affects their response to the male effect. Appl. Anim. Behav. Sci. 84, 119–126. Anderson, K.L., Hunt, E., Davis, B.J., 1991. The influence of antiinflammatory therapy on bacterial clearance following intramammary Escherichia coli challenge in goats. Vet. Res. Commun. 15, 147–161. Barroso, F.G., Alados, C.L., Boza, J., 2000. Social hierarchy in the domestic goat: effect on food habits and production. Appl. Anim. Behav. Sci. 69, 35–53. Bøe, K.E., Færevik, G., 2003. Grouping and social preferences in calves, heifers and cows. Appl. Anim. Behav. Sci. 80, 175–190. Gelez, H., Lindsay, D.R., Blache, D., Martin, G.B., Fabre-Nys, C., 2003. Temperament and sexual experience affect female sexual behaviour in sheep. Appl. Anim. Behav. Sci. 84, 81–87. Hasegawa, N., Nishiwaki, A., Sugawara, K., Ito, I., 1997. The effects of social exchange between two groups of lactating primiparous heifers on milk production, dominance order, behavior and adrenocortical response. Appl. Anim. Behav. Sci. 51, 15–27. Kondo, S., Hurnik, J.F., 1990. Stabilization of social hierarchy in dairy cows. Appl. Anim. Behav. Sci. 27, 287–297. National Research and Council, 1985. Nutrient Requirements of Goats. National Academy Press, Washington, DC.
Sevi, A., Taibi, L., Albenzio, M., Muscio, A., Dell’Aquila, S., Napolitano, F., 2001. Behavioral, adrenal, immune, and productive responses of lactating ewes to regrouping and relocation. J. Anim. Sci. 79, 1457–1465. Shamay, A., Shapiro, F., Barash, H., Bruckental, I., Silanikove, N., 2000a. Effect of dexamethasone on milk yield and composition in dairy cows. Ann. Zootech. 49, 343–352. Shamay, A., Mabjeesh, S.J., Shapiro, F., Silanikove, N., 2000b. Adrenocorticotrophic hormone and dexamethasone failed to affect milk yield in dairy goats: comparative aspects. Small Rumin. Res. 38, 255–259. Silanikove, N., 2000. The physiological basis of adaptation of goats in harsh environments. Small Rumin. Res. 35, 181–193. StatSoft Inc., 1998. STATISTICA for Windows [Computer program manual]. StatSoft Inc., Tulsa, OK. Stewart, H.J., Thompson, G.E., 1984. Adrenocorticotrophic hormone stimulation of mammary secretion in lactating goats independent of increased mammary uptake of glucose. J. Endocrinol. 101, 203–211. Varner, N.A., Johnson, B.H., 1983. Influence of adrenocorticotrophin upon milk production, milk constituents, and endocrine measures of dairy cows. J. Dairy Sci. 66, 458–465. Veissier, I., Boissy, A., dePassille, A.M., Rushen, J., van Reenen, C.G., Roussel, S., Andanson, S., Pradel, P., 2001. Calves’ responses to repeated social regrouping and relocation. J. Anim. Sci. 79, 2580–2593.
Regrouping in lactating goats increases aggression and decreases milk production M.A. Fern´andez a , L. Alvarez a,b,∗ , L. Zarco a a
Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Aut´onoma de M´exico, Ciudad Universitaria, Ciudad de M´exico 04510, Mexico b Centro de Ense˜ nanza Pr´actica e Investigaci´on en Producci´on y Salud Animal, Cruz Blanca 486, San Miguel Topilejo, Tlalpan, Ciudad de M´exico 14500, Mexico Received 14 March 2006; received in revised form 14 March 2006; accepted 22 March 2006 Available online 19 May 2006
Abstract With the aim of testing the hypothesis that regrouping decreases milk production in French Alpine goats that were lactating, a study was done using two groups (n = 8, 7). During their third month after parturition, four goats from each group were exchanged (first regrouping) between pens and left for 2 weeks, then the same two subgroups of four goats were taken back to their original pen for another 2 weeks (second regrouping). In the third regrouping, the two groups were all placed in the one pen. Milk production and social behaviour were measured daily before and after each regrouping. All regroupings led to an increase in aggressive behaviours that last by 1–2 days. Mean daily milk production decreased after first (2.82 ± 0.2 kg versus 2.53 ± 0.2 kg; P < 0.05) but not after second and third regrouping. It is concluded that aggressive behaviour increases after all regroupings, whereas milk production decreases only after the first regrouping, suggesting an important capacity of adaptation to a novel and stressful managements in the French Alpine goat. The study highlights the importance of considering effects of common practices in herd managements on social behaviour and production. © 2006 Elsevier B.V. All rights reserved. Keywords: Regrouping; Social behaviour; Goat; Social dominance; Milk production
1. Introduction In modern and high-producing dairy herds, regrouping according to age, nutrient requirements, body condition, lactation period and level of milk yield, is a common practice of management to enhance productivity and profitability. Mixing unfamiliar animals is also common in fattening animals. However, as a result of the vigorous fighting associated with the establishment of a
∗ Corresponding author. Tel.: +52 55 58 48 05 15; fax: +52 55 58 48 05 14. E-mail address: [email protected] (L. Alvarez).
0921-4488/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.smallrumres.2006.03.008
new social hierarchy, the practice may temporally disturb social structure of the herd, which may distress animals and have adverse effects on milk production (Bøe and Færevik, 2003). In heifers (Hasegawa et al., 1997), social structure is affected by regrouping, provoking an increase in aggressive behaviour and a decrease in milk production, specially in the subordinate animals. Goat is a very hierarchical species, with a very clear structure of dominance and an almost linear social hierarchy (Addison and Baker, 1982; Barroso et al., 2000; Alvarez, 2004). In feral herds of this species (Alley and F´ordham, 1994), introduction of new members to an established group leads to a significant increase in
M.A. Fern´andez et al. / Small Ruminant Research 70 (2007) 228–232
aggression, temporally disrupting social structure and interfering with normal activities as feeding. Disruption of social organization in French Alpine goats as a consequence of regrouping might also negatively affect milk production. This study was done to test the hypothesis that introduction of new members to an established group of French Alpine goats leads to an increase in aggression and a decrease in milk production. 2. Materials and methods The study was carried out on an experimental intensive farm located close to Mexico City (2760 m above sea level, 19◦ 13 N, 99◦ 8 W) using a protocol that had been approved by the Internal Animal Ethics Committee of the Faculty of Veterinary Medicine and Zootechnie. Two groups (n = 8, 7) of lactating French Alpine goats, 28.0 ± 2.64 months old were used; all goats were in their first (11 does) and second (four does) lactation. Groups of same average age (30.7 ± 4.08 and 24.8 ± 3.2 months) were formed at the moment of parturition, and remained in different 160 m2 pens separated by 20 m. During their whole pregnancy time, goats were all together in the same pen until the day of parturition. Milk production per week was measured from day 5 after parturition in all goats (except during the regroupings period). Three months after parturition, four goats of similar age from each group were selected randomly and exchanged (first regrouping) between pens and left for 2 weeks, then the same two subgroups of four goats were taken back to their original pen for another 2 weeks (second regrouping). In the third regrouping, the 15 goats of both groups were all placed in the one pen. From 2 weeks before the first regrouping and until 2 weeks after the third, milk production was measured daily. At the same time, the behaviour of the goats was studied for 4 h/day to determine the levels of aggression. The behaviours recorded were: butts, when the goat used the front of her head to make contact with another goat; chases, when a goat actively moved towards another individual, causing the latter to walk or run away; threats, when a goat turned towards or approaches another individual with head down and then lunges without making contact; displacements, when a goat actively moved away from another individual whether or not previous interaction has occurred between the two individuals; and bites, when the goat used her mouth and tooth to attack another individual, as described by Alvarez et al. (2003); the initiator, winner and loser of each interaction were recorded and the end of an interaction was recorded when one of the animals involved withdrew or displaced; this information was used both, to determine the changes in the
229
aggression activity, and also to calculate an individual index of success (IS) in agonistic interactions and to create three ranking (high, medium and low) groups using the procedure described by Alvarez et al. (2003). Briefly, index of success was calculated using the formula: IS =
Number of goats that an individual displaces (Number of goats that an individual displaces + Number of goats that displace the individual)
High ranking goats were those whose SI was from 1.0 to 0.667, IS of medium ranking goats was from 0.666 to 0.334, and IS of low ranking goats was from 0.333 to 0.0. In addition, the number of times each goat visited the feeder was also recorded during these observations, using scan sampling (every 5 min). All goats were weighed every week. The goats were fed with a silage-based diet with oat and concentrate three times per day, at 08:00, 12:00 and 15:00 h (meeting the requirements of the National Research Council, 1985). Feed was provided in a 9 m long feeder, and water was provided ad libitum. 2.1. Data analysis Data were analyzed using t-test for related samples, analysis of variance and Duncan’s test. Behavioural information was analyzed using Kruskall–Wallis and Mann–Whitney tests. All the analysis was done using the Statistica software of StatSoft© (StatSoft, 1998). Means are ±standard error. 3. Results Frequency of registered aggressive behaviours were notably increased during all regroupings, especially during regroupings one and three (Fig. 1). Aggression was higher during the day of regrouping and tended to decrease to pre-regrouping levels the day after regrouping (Fig. 1). Mean daily milk production decreased after first regrouping (P < 0.05; Table 1). The mean decrease in milk production was of 10% in the week after regrouping compared with the week before (Table 2). There were not significant changes in daily milk production after second and third regroupings (Table 1). At the end of the experiment, three goats were classified as high, seven as medium and five as low rank. Most goats had consistently the same IS and rank position during regroupings, only two goats changed their position from low to medium and from medium to low rank, respectively. Daily milk production (kg ± S.E.)
230
M.A. Fern´andez et al. / Small Ruminant Research 70 (2007) 228–232
4. Discussion
Fig. 1. Frequency (events/h) of the recorded behaviours (bites, threats, butts and displacements) before and after each regrouping. Note the different scale in Y-axis of the third graphic.
was higher in goats of medium rank (2.99 ± 0.26) than in goats of high rank (2.03 ± 0.42; P = 0.06) and similar to goats of low rank (2.31 ± 0.24). Total milk production during the complete experiment was also higher in medium rank goats (212.5 ± 19.0) than in high rank goats (144.48 ± 30; P = 0.06). Frequency of visits to the feeder did not differ between the high, medium and low ranking group (2.5 ± 0.1, 3.2 ± 0.3 and 2.9 ± 0.4, respectively).
Table 1 Daily milk production (mean, kg ± S.E.) during 1 week before and 1 week after each regrouping of the 15 French Alpine goats Regrouping
Week before
Week after
First Second Third
2.82 ± 0.22 a 2.47 ± 0.19 a 2.43 ± 0.20 a
2.53 ± 0.21 b 2.47 ± 0.17 a 2.41 ± 0.18 a
a, b different letters between columns indicate significance (P < 0.05).
As expected, regrouping of the French Alpine goats led to an increase in aggressive interactions, suggesting a temporal disruption of the social structure of the herd. This is in agreement with what Addison and Baker (1982) found in feral goats. In all cases, 3 days after regrouping aggression implying physical contact was in the same level as before mixing the animals, which indicates that in the used size of groups, 3 days was time enough for the social organization to be reestablished. Changes in social behaviour after regrouping followed what Kondo and Hurnik (1990) predicted for cattle, with the ratio of physical to non-physical interactions remaining comparatively stable. It is well accepted that increased aggression after regrouping is a stressful situation for animals, and the negative effects of regrouping have been tough to be caused by the stress hormones, aimed ACTH and cortisol. A decrease in milk production has been reported in cows when ACTH or corticoids are elevated or injected (Varner and Johnson, 1983; Shamay et al., 2000a), however, same treatments in goats have shown inconsistent results, increasing (Stewart and Thompson, 1984) or having no effects (Anderson et al., 1991; Shamay et al., 2000b) on milk yield. The formerly two mentioned studies did not use a social environment disturbed by aggression, were the effect of the stress hormones could probably be more intense. During the time the social structure of the group is being reestablished after regrouping, increased aggression could also affect feeding, decreasing the amount of food that some goats consume. Thus, decrease in daily milk production after first regrouping might be a consequence not only of the augmented aggression, but also of the social stress and differences in food consumption during that time. In deciding whether an animal is affected or not by the social perturbation, social dominance before regrouping seems to be important. Similar findings suggesting the relevance of social dominance have been published by Hasegawa et al. (1997) in heifers, with the dominant individuals being the less affected. No effects on milk production after the second/third regroupings might indicate an important capacity of adaptation to a novel and stressful repeated management in these goats. In that regard, time between each regrouping could also be important, as it probably was not long enough to make the animals unfamiliar. Although it has been said that goats are better adapted to harsh environmental conditions than other domesticated ruminants and that this is reflected in attenuated response to stressful conditions (Silanikove, 2000), other ruminants have
M.A. Fern´andez et al. / Small Ruminant Research 70 (2007) 228–232
231
Table 2 Daily milk production (mean, kg ± S.E.) and its changes during the week before (week −1) and after (week 1) the three regroupings in goats according with their social dominance and whether they remained or were moved from their original pen Week −1 (kg) First regrouping High dominance, remained (3) Medium dominance, remained (3) Low dominance, remained (1) All (7) Medium dominance, moved (4) Low dominance, moved (4) All (8) Second regrouping High dominance, remained (3) Medium dominance, remained (3) Low dominance, remained (1) All (7) Medium dominance, moved (4) Low dominance, moved (4) All (8) Third regrouping High dominance (3) Medium dominance (7) Low dominance (5) All (15)
Week −1 (%)
Week 1 (kg)
0.13 0.24 0.25 0.16
100 100 100 100
1.88 3.18 1.24 2.1
0.12 0.21 0.07 0.14
87.96 91.11 79.13 87.56
−12.04 −8.89 −20.87 −12.44
3.23 ± 0.08 2.74 ± 0.08 2.98 ± 0.07
100 100 100
2.87 ± 0.06 2.52 ± 0.07 2.69 ± 0.05
88.96 91.99 90.35
−11.04 −8.01 −9.65
± ± ± ±
0.13 0.18 0.06 0.13
100 100 100 100
2.06 3.08 1.41 2.18
± ± ± ±
0.14 0.14 0.02 0.12
101.44 96.03 94.75 97.38
+ 1.44 −3.97 −5.25 −2.62
2.69 ± 0.07 2.29 ± 0.11 2.49 ± 0.07
100 100 100
2.72 ± 0.04 2.37 ± 0.07 2.55 ± 0.05
101.03 103.68 102.25
+1.03 +3.68 +2.25
± ± ± ±
100 100 100 100
1.96 2.77 1.96 2.23
± ± ± ±
103.57 97.76 103.33 101.02
+3.57 −2.24 +3.33 +1.02
2.14 3.49 1.57 2.40
2.03 3.21 1.49 2.24
1.89 2.83 1.89 2.20
± ± ± ±
0.13 0.19 0.03 0.13
± ± ± ±
0.14 0.21 0.14 0.13
Week 1 (%)
Change (%)
Week −1: week before regroupings. Week 1: week after regroupings. Data in parenthesis indicates number of goats.
also shown a good capacity for habituation to regrouping (calves, Veissier et al., 2001), and lactating ewes show only short term effects on production performance when under the same management (Sevi et al., 2001). Goats differed in their milk production according to their social position. Unexpectedly, goats that were in medium rank produced more than high-ranking does. In Spanish breed goats (Malague˜na, Serrana, Granadina), does of intermediate rank are also the most productive (Barroso et al., 2000). There is not a very clear explanation for such a difference in milk production, Barroso et al. (2000) have proposed that middle-ranking goats could suffer from less social pressure than the animals of inferior status and, at the same time not have to expend energy in continual aggression to maintain their position as with the most dominant animals. In this possible “social strategy” for not to spend too many energy, which is observable in a better productive performance, a clear and identifiable behavioural pattern could be being displayed, it is interesting that this social strategy might be selected to improve the herd productivity. Similar selection has been done according to temperament in sheep, achieving successful results in improving lamb’s viability and female’s sexual behaviour (Gelez et al., 2003).
It is concluded that aggressive behaviour increases after all regroupings, whereas milk production decreases only after the first regrouping, suggesting an important capacity of adaptation to a novel and stressful managements in the French Alpine goat. The study highlights the importance of considering effects of common practices in herd managements on social behaviour and production. Acknowledgements The study was partially supported by Consejo Nacional de Ciencia y Tecnolog´ıa (CONACYT, grant 34924-B) and Programa de Becas para Tesis de Licenciatura (PROBETEL, grant for Adri´an Fern´andez). References Addison, W.E., Baker, E., 1982. Agonistic behavior and social organization in a herd of goats as affected by the introduction of non-members. Appl. Anim. Ethol. 8, 527–535. Alley, J.C., F´ordham, R.A., 1994. Social events following the introduction of unfamiliar does to a captive feral goat (Capra hircus L.) herd. Small Rumin. Res. 13, 103–107. Alvarez, L., 2004. Efecto de la dominancia social sobre la efectividad de la inducci´on de actividad ov´arica en cabras an´estricas medi-
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