Effects of outdoor winter housing and feeding level on performance and blood metabolites of suckler cows fed whole-crop barley silage

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Livestock Science 115 (2008) 179 – 194 www.elsevier.com/locate/livsci

Effects of outdoor winter housing and feeding level on performance and blood metabolites of suckler cows fed whole-crop barley silage M. Manninen a,⁎, S. Sankari b , L. Jauhiainen c , T. Kivinen d , P. Anttila e,1 , T. Soveri f a MTT Agrifood Research Finland, Animal Production Research, FIN-31600 Jokioinen, Finland University of Helsinki, Faculty of Veterinary Medicine, Department of Equine and Small Animal Medicine, FIN-00014 University of Helsinki, Finland c MTT Agrifood Research Finland, Services Unit, FIN-31600 Jokioinen, Finland d MTT Agrifood Research Finland, Animal Production Research, FIN-03400 Vihti, Finland University of Helsinki, Faculty of Veterinary Medicine, Department of Basic Veterinary Sciences, FIN-00014 University of Helsinki, Finland f University of Helsinki, Faculty of Veterinary Medicine, Department of Production Animal Medicine, Pohjoinen pikatie 800, FIN-04920 Saarentaus, Finland b

e

Received 28 February 2007; received in revised form 5 July 2007; accepted 7 July 2007

Abstract The experiment studied the effects of long-term cold climatic housing conditions at a latitude of 62°N on pregnant Hereford cows and their progeny. Thirty-five cows in their third parity were overwintered in outdoor facilities with either a rain-shelter or a three-wall shelter, or in an uninsulated barn. Whole-crop barley silage was offered to the cows either ad libitum or restricted supplemented with oats. The dry matter intake on the restricted diet was 75% of that on the ad libitum diet. The cow live weight (LW) averaged 670 kg at the onset of the experiment. During winter the cows outdoors on the restricted diet maintained their LW while those on the ad libitum diet gained LW (P b 0.05, − 3 vs. 41 kg). On pasture, the LW gain (LWG) was 61 and 32 kg (P b 0.05) for the cows overwintered outdoors on the restricted and on the ad libitum diets, respectively. The initial body condition score (BCS, Scale: 0–5) of the cows averaged 2.90. During winter the cows outdoors on the restricted diet decreased and those on the ad libitum diet increased the BCS (P b 0.01, − 0.14 vs. 0.21). On pasture, the cows overwintered outdoors on the restricted diet increased the BCS more than those overwintered on the ad libitum diet (P b 0.05, 0.31 vs. 0.08). No signs of extraordinary stress, massive consumption of energy stores, frequent muscle injuries or severe inflammations occurred in any of the groups according to blood analyses of cows, e.g. cortisol, long-chain fatty acids, aspartate aminotransferase, creatine kinase and white blood cell count. The calving period was from 11 March to 21 April. Only one indoor calving was classified as difficult due to faulty disposition leading to the loss of the calf. All outdoor calvings were easy. The LWG of the indoor calves of cows on the ad libitum diet was poorer (P b 0.05) pre the grazing period than that of the outdoor calves of cows on the ad libitum diet. On pasture and during the entire experiment the LWG was similar for all calves, averaging 1335 and 1251 g/d, respectively. The breeding season was 82 days. Thirty cows out of 33 were observed to be pregnant after the mating period. All the facilities offered adequate shelter for the mature, pregnant suckler cows. The restricted offering of wholecrop barley silage provided, on average, 101 MJ metabolizable energy/d and gave enough energy for the cows. © 2007 Elsevier B.V. All rights reserved. Keywords: Blood metabolites; Claw; Housing; Suckler cow; Whole-crop barley silage

⁎ Corresponding author. Present address: Hutkankatu 8, FIN-30420 Forssa, Finland. Tel.: +358 40 735 5061. E-mail address: [email protected] (M. Manninen). 1 Present address: Valkamantie 9, FIN-71750 Maaninka, Finland. 1871-1413/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2007.07.014

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1. Introduction Winter housing expenses play a considerable role in northern latitudes where insulated winter buildings are typically used not only for dairy cows and growing cattle but also for suckler cows. Rising housing costs have created a demand for inexpensive winter housing systems. One method of reducing costs is to winter suckler cows outdoors. Suckler cows have lower demands for housing facilities and feeding than high-producing dairy cows. The effects of cold climatic conditions on the performance and welfare of growing cattle are welldocumented. In most cases, cold conditions or absence of shelters have affected animal performance negatively (e.g. Birkelo et al., 1991; Delfino and Mathison, 1991; Kubisch et al., 1991) or have changed animal behaviour (Redbo et al., 2001). On the contrary, McCarrick and Drennan (1972a,b) and Redbo et al. (1996) reported no negative effects on animal health and live weight gain. According to Malechek and Smith (1976), Hereford cows altered their daily behavioural routines in response to changes in weather conditions, when little natural and no artificial shelter were provided. However, the effects of outdoor wintering on the performance of mature suckler cows and especially on cow physiology are less well documented. Wassmuth et al. (1999) reported that suckler cows in severe weather conditions reduce their motor activity and remain near the feeding point. According to Lowman (1997) feed costs account for about 75% of the total variable costs for both autumn and spring calving herds. Furthermore, 80% of total feed costs are aroused by the cow herself. Therefore, the possibility to restrict the amount of winter feed without detrimental effects on cow or calf performance is essential in reducing production costs. In northern latitudes where year-round grazing is not possible, winter feeding of suckler cows is generally based on inexpensive or alternative feeds such as straw, treated straw, feed industry by-products or whole-crop cereal silages (Manninen et al., 2000, 2004, 2005). In cold conditions, whole-crop cereal silage has proved to be an acceptable winter feed for suckler cows due to its non-freezing property (Manninen et al., 2005). Using pregnant beef cows Young (1975) studied the effects of winter acclimatization on the energy metabolism of mature cows and concluded that the metabolic rate was not significantly influenced by either the body condition or by the availability of bedding. Information on the effects of long-term cold climatic conditions on the blood parameters of mature, pregnant suckler cows is, to our knowledge, not available. In the present study, the purpose of comparing the feeding strategies was to study whether the mature

suckler cows can be kept on restricted amounts of feeds without detrimental effects of cold. The working hypothesis of the present study was that mature, pregnant spring-calving suckler cows can be overwintered outdoors in a cold climatic environment in inexpensive housing facilities on restricted amounts of feeds without negative effects on body weight and condition score, calving difficulty of dams and on the growth of their calves. Selected blood analyses were presumed to be more sensitive indicators than production performance to detect any signs of subclinical infections, imbalance in energy metabolism or uncomfortableness caused by cold housing conditions and feed restriction. The present study evaluated the effects of long-term cold conditions on Hereford cows and their progeny overwintered in different housing facilities and offered whole-crop barley silage (WCBS) either ad libitum or restricted supplemented with oats. The effects were studied by evaluating the cow and calf live weight, cow body condition, dystocial cases, cow maternal instincts, reproduction, claw health and blood constituents. 2. Material and methods 2.1. Animals and experimental design Thirty-five Hereford (Hf) cows with an initial live weight (LW) of 670 kg (Standard Deviation, S.D., 71.6) and body condition score (BCS, Scale: 0–5) of 2.90 (S.D. 0.319) on 2 November were selected for the experiment. The animals comprised 33 third-calving and two second-calving cows, all born in the same year and pregnant to a Hf bull. The experiment consisted of two main periods, a winter feeding period and a grazing period averaging 212 (S.D. 0.5) and 94 (S.D. 0.5) days, respectively. The experiment commenced on 3 November and the grazing season started on 2 June. The experiment ended with the weaning of the calves on 4 September. There were seven animals per treatment. The five treatments imposed on the cows during the winter period were: I) outdoors with a rain-shelter having ad libitum WCBS (AS) II) outdoors with a rain-shelter having restricted WCBS (RS) III) outdoors with a three-wall shelter having ad libitum WCBS (AT) IV) outdoors with a three-wall shelter having restricted WCBS (RT) V) indoors having ad libitum WCBS (AU). The treatment Indoors and having restricted WCBS is missing due to lack of housing facilities. The predicted calving date (gestational age assessed by ultrasonographic foetometry after natural mating), initial LW and BCS (Scale: 0–5) were

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used to allocate the animals to the treatments. The experiment was carried out at Tohmajärvi Research Station located in eastern Finland (62°20'N, 30°13'E) where the average growth period is 155 days (base temperature + 5 °C) and grazing period 100–120 days. 2.2. Winter housing facilities During the winter period, the AU group was confined in an uninsulated barn in one pen of a total of 74 m2 including 53 m2 of bedding area and 21 m2 of passage. Straw and peat were used as bedding materials. The AU cows had access to an outside exercise area of 106 m2 for 2 h two to three times weekly while bedding material was added. The four outdoor groups were housed in an area of 1000 m2 each in the nearby forest beside the uninsulated barn. A rain-shelter with a roof (52 m2) without bedding was built for the AS and RS groups and divided equally between them. Both rain-shelter areas were equipped with an uncovered 56 m2 sleeping area based on sawmill by-products and straw as bedding materials. A shelter with three walls and a roof (100 m2) was built for the AT and RT groups and divided equally between them. Straw and sawmill by-products were used as bedding materials in the three-wall shelter. In the three-wall shelter and in the uncovered sleeping areas bedding material was added as necessary. All four outdoor areas were equipped with Lshaped wind breaks (side lengths 3.5 and 14.0 m, height 2.3 m, with a 3-cm space between boards) in one corner nearby the uncovered sleeping areas. 2.3. Weather conditions The minimum and maximum temperatures, the air humidity and the wind speed were recorded outdoors daily at 8:00 a.m. and 2:00 p.m., and the snow depth once daily. The minimum and maximum temperatures and the air humidity were recorded indoors daily at 8:00 a.m. and 2:00 p.m. The wind-chill factor was calculated according to NOAA (2004). 2.4. Feeds and feeding In the AS, AT and AU treatments, WCBS was offered to the cows ad libitum during the entire winter period. In the RS and RT treatments, the winter feeding comprised of three periods. The first period was from the start of the experiment to the onset of pre partum feeding (87 days, S.D. 2.1), the second period was the pre partum feeding (61 days, S.D. 12.4), and the third period was the post partum feeding (65 days, S.D. 11.2). The cows were fed restricted amounts of WCBS supplemented with milled oats grain. The total yield of WCBS was lower than evaluated. Therefore, to ensure the sufficiency of the experimental WCBS during the entire winter feeding period milled oats was offered to the cows in the treatments RS and RT 2.16 kg dry matter (DM)/d pre calving and 3.45 kg DM/d post calving. The animals were group-fed, once daily in the morning. The RS and RT cows had no opportunity to steal feed from the AS and AT cows. The animals were tied up for maximum 2 h post the feeding so that everyone could get her own portion, especially

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oats in the RS and RT treatments. Oats was given in the RS and RT treatments individually, and after that WCBS was given. The amount of feed offered and refused was recorded for each group daily. There are no official feeding recommendations for suckler cows in Finland and therefore, the restricted feeding was based on the recommendations for dairy cows (Tuori et al., 1996). The cows were assumed to produce 10 kg milk per day. Maintenance recommendation was documented as 8.31 MJ ME+ 0.091 ×LW. The cow LW at the onset of the experiment was used for calculation. Energy needed for pregnancy was calculated using the recommendation for the last two months for dairy cows, i.e. 18.72 and 33.93 MJ ME/d. Additionally, 5.15 MJ ME× kg energycorrected milk was calculated for milk production. The WCBS was harvested at dough stage of maturity on 4 and 5 August with a double-chopper and ensiled in bunker silos using a formic acid-based additive (AIV 10 Plus: 734 g formic acid/kg, 56 g ammonium formiat/kg, Kemira Oyj, Oulu, Finland), applied at 5 l/t. Oats was harvested conventionally. The chemical composition of the WCBS (crude protein (CP) content 99 g/kg DM) was analyzed prior to the experiment and its calculated energy value of 9.36 MJ ME/kg DM was used to formulate the restricted feeding scheme. During winter the cows had free access to a mineral mixture rich in phosphorus (Fosfori Hertta–Minera Muro: Ca 105 g/kg, P 116 g/kg, Na 70 g/kg, Mg 75 g/kg, Suomen Rehu Oy, Vaasa, Finland), a salt-lick and water. A vitamin mixture (ADEK3-Kotieläinten vitamiiniliuos: A 30000 International Unit (IU)/ml, D3 2500 IU/ml, E (DL + αtocopherol acetate) 60 mg/ml, DL +α-tocopherol 54 mg/ml, K3 4 mg/ml, Hiven Oy, Paimio, Finland) was given to the cows 20 ml once a week, before offering the feeds. For mating the cows were divided into two groups, both groups consisting of half of the cows from each treatment group. Two Hf bulls ran with the cows from 15 June to 4 September. All the animals grazed on timothy-dominated pastures which were rotationally grazed with an area on average 0.56 ha per cow–calf pair until mid-July and thereafter 0.67 ha per cow–calf pair until the end of the grazing season. The cows had free access to water and a mineral mixture rich in magnesium (Viher Hertta–Minera Muro: Ca 160 g/kg, P 64 g/kg, Na 90 g/kg, Mg 80 g/kg, Suomen Rehu Oy, Vaasa, Finland). 2.5. Sampling and analysis of feed and blood Feed samples for chemical analyses were taken at every feeding and pooled over a four-week period. The WCBS DM content was determined by oven drying at 105 °C for 16 h and corrected for volatile losses according to Huida et al. (1986). Feed samples were analysed for ash (AOAC, 1990, No. 942.05), for total nitrogen (N) by the Dumas method using a Leco FP 428 nitrogen analyser (AOAC, 1990, No. 968.06, Leco Corp., St Joseph, MI 49085, USA) and for neutral detergent fibre (NDF) according to Van Soest et al. (1991). Starch was measured according to Bach Knudsen et al. (1987). In vitro organic matter digestibility (OMD) was measured by using cellulase enzyme complex according to Friedel (1990). Fresh WCBS samples were analysed for pH, water-soluble

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carbohydrates by the method of Somogyi (1945), lactic acid (Haacker et al., 1983), volatile fatty acids (Huhtanen et al., 1998), ammonia N (McCullough, 1967), ethanol with an enzymatic kit (Cat No. 981680, KONE Instruments Corporation, Espoo, Finland) and soluble N by the Kjeldahl method using Cu as a digestion catalyst (AOAC, 1990, No. 984.13). The ME content of the WCBS was calculated assuming a ME content of 15.5 MJ/kg digestible organic matter (DOM) according to MTT (2004). The D value (DOM in DM) was based on in vitro measurement. Amino acids absorbed in the small intestine (AAT) were calculated using the measured D value and the CP content (MTT, 2004). The feed value of the oats was calculated using the determined chemical composition and average digestibility coefficients by MTT (2004). Blood samples were taken from cows at 7:00–8:00 a.m. before morning feeding from the jugular vein into evacuated ethylenediaminetetraacetic acid (EDTA), heparinized and plain tubes on 29 October, 18 November, 16 December, 13 January, 10 February and 10 March. For glucose and βhydroxybutyrate (β-HB) analyses a portion of the heparinized blood was immediately precipitated with ice-cold 0.6 N perchloric acid and frozen. The serum was separated, frozen in portions and stored at − 70 °C until analysed. Blood haemoglobin (Hb) and the leukocyte (WBC) count were determined from the EDTA blood by an automatic cell-counter adjusted for animal-cell counting (Coulter Counter T850, Coulter Electronics LTD, Luton, England). Before the analysis of β-HB and glucose, the acidified blood samples were centrifuged and the supernatant was neutralized with KOH, kept in an ice-bath for 30 min and then centrifuged. The clear supernatant was used for an enzymatic determination of β-HB (Hansen and Freier, 1978) and glucose (Trinder, 1969). The activities of serum aspartate aminotransferase (ASAT, EC 2.6.1.1) and creatine kinase (CK, EC 2.7.3.2) were determined according to the recommendations of the Committee on Enzymes for the Scandinavian Society for Clinical Chemistry and Clinical Physiology (1974, 1976). Total protein was determined by the biuret method (Weichselbaum, 1946). Urea was measured by a kinetic enzymatic method (Guttman and Bergmeyer, 1974). An enzymatic, colorimetric method was used for the determination of long-chain fatty acids (LCFA, NEFA-C, Waco Chemicals GmbH, Neuss, Germany). Serum leptin concentration was determined using the Linco Multispecies Ria Kit (Cat. No. XL-85 K, Linco Research, St. Charles, MO, USA) and serum cortisol concentration using radioimmunoassay (Coat-A-Count Cortisol, Diagnostic Products Corp., Los Angeles, CA, USA). The cortisol assay was modified by preparing a low standard point of 13.9 nmol/l by diluting the calibrator C (139.3 nmol/l) 1:10 with the zero calibrator of the kit. 2.6. Animal performance and claw health The cows were weighed at the onset of the experiment, 1– 7 days pre partum, within 48 h after parturition, at the onset and at the end of grazing period on two consecutive days. The cows were condition-scored (Lowman et al., 1976) when weighed except pre calving. The cleanness of the cows was

recorded daily by visual assessment of the group using the scale dry = 1, wet = 2, snowy = 3 and muddy = 4 combined with the values of clean = 1, medium dirty = 2 and dirty = 3. Calves were weighed immediately after birth, at 14 and 50 days of age, at the onset and at the end of the grazing period. All calvings were monitored and assistance was given as described by Manninen et al. (2000). The calving place in the outdoor facilities was registered. Cow maternal instinct was recorded using a scale 1 = good, 2 = nonchalant and 3 = angry towards her calf. Because one AS and one AU cow lost their calf immediately after birth only the birth LW is available for these calves. Data from one pair of twins born in the treatment AT were excluded. All cows except those AS and AU cows excluded due to calf losses were included in the pregnancy rates. The claw health of the outdoor cows was monitored on 17 November, 10 January, 16 March and 12 June. The hind feet were examined in the claw trimming box. The foot was lifted up and a thin layer was removed from the sole with an angle grinder. The changes in the sole were monitored by a modified method described by Bergsten (1993). The changes monitored were sole haemorrhages and white line rupture. Each change was scored separately on a scale 0–3 where 0 = no change, 1 = mild change, 2 = moderate change and 3 = strong change. Changes were scored separately for the inner and outer claw of the hind feet. The sum of these scores was used to indicate the claw health of the cow. The possible variation in the total score could be 0–12. Ultrasonographic examinations were performed on 10 August, 7 September and 8 October to assess the status of pregnancy and gestational age. A real-time B-mode ultrasound scanner (Aloka SSD-210DX, Aloka Co. Ltd., Japan) equipped with a 5.0 MHz rectal linear array transducer was used for ultrasound examinations. Gestational age was assessed by ultrasonographic foetometry based on measurements of foetal diameter of the external braincase or crown-rump length. Gestational age and thus date of conception were calculated according to Kähn (1989). 2.7. Statistical analysis The experiment had five treatments and seven animals per treatment. The amount of information can be gained using preplanned comparisons which takes into account more than two treatments at one comparison (Mize and Schultz, 1985). In the current experiment, comparisons among treatments were done using seven pre-planned comparisons which were housing-byfeeding interaction without treatment AU because the levels of the treatments were not arranged factorially, difference between three housings when ad libitum feeding, difference between two housings when restricted feeding, the main effect of housing without treatment AU, difference between two feedings in rainshelter housings, difference between two feedings in three-wall shelter housings, and the main effect of feedings without treatment AU. Two main-effect comparisons were reasonable only if the housing-by-feeding interaction was not statistically significant, while four remaining comparisons were reasonable if interaction was significant. The P values 0.06–0.10, which are

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near the statistically significant value of 0.05 were presented at tables to show tendency. All cow blood values, LW, BCS and calf LW were measured at five to six different times during the study. Possible correlation of repeated measures taken from the same animal was taken into account in the following model: yijk ¼ l þ treatmenti þ timek þ time  treatmentik þ eijk

where μ, treatmenti, timek, time × treatmentik represent the intercept and the fixed effects of treatments, measurement time and their interaction, respectively, εijk represent the normally distributed residuals of the jth animal and the residuals from the same animal are correlated. The covariance structures for repeated measures were selected from among several structures using Akaike's information criterion (Wolfinger, 1996) and compound symmetry (BCS), heterogeneous compound symmetry (LW) or unstructured (calf LW and most of the blood values) covariance structure were used in the final analysis. The amount of random variation varied from time to time, except in analysis of BCS and used covariance structures takes into account this variation. The unstructured covariance structure allows that correlation between repeated measurements depends on time lag between measurements. In the analysis of calf LW the sex was added to the statistical model. Moreover, the difference between sexes was allowed to change during the study, but the difference between sexes was assumed to be equal for all treatments. Both assumptions were verified using graphical plots. Initial values measured at October were used as a covariate in analyses of blood values. Statistically significant effect for initial values was not found in four analyses (WBC, urea, CK and glucose). The parameters of the models were estimated by the REML method using the SAS system (1999, release 8.2) and the MIXED procedure. The adequacy of the models was checked through graphical analysis of the residuals. The residuals were plotted against the fitted values for each measurement time separately. The normality assumption of the residuals was checked by using the box plot. Normality was achieved after logtransformation of the data in three statistical analyses of blood values (CK, β-HB and serum cortisol). All presented estimated means or differences were transformed to the original scale. The standard error of the estimated means or differences, however, could not be transformed to the original scale.

3. Results 3.1. Weather conditions and cow comfort The snow cover in the outdoor facilities grew steadily during the winter, reaching a depth of 1 m in mid-March (Fig. 1). In February and March, the minimum temperature outdoors was −20 °C or lower on 19 and 18 days, respectively. In May, the minimum temperature outdoors

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was observed to be below 0 °C on 11 days. The wind speed remained mainly below 5 m/s but occasionally rose to 5–10 m/s. Indoors the minimum temperature was observed only once in mid-February to be below −20 °C (Fig. 2). In February and March, the temperature indoors at 8:00 a.m. was on average 7 °C higher than outdoors. The air humidity outdoors at 8:00 a.m. and 2:00 p.m. was on average 95 and 90% in November–March, and indoors 95 and 92%, respectively. The rain-shelter cows were assessed as dry, wet, snowy or muddy on 64.5, 5.6, 18.9 and 11.0% of the observed days during winter, respectively. The corresponding values for the three-wall shelter cows were 84.4, 3.5, 5.1 and 7.0%, respectively. Indoor cows were always evaluated as being dry. The rain-shelter cows were clean on 209 out of 214 days and medium dirty on five days. The three-wall shelter cows were clean on 212 out of 214 days and medium dirty on two days. The cows were clean on 207 out of 214 days and medium dirty on seven days when kept indoors. 3.2. Feeds and feed intake The mean chemical composition and feed values of the experimental feeds are presented in Table 1. The daily DM, ME and protein intakes during the winter period are presented in Table 2. Cows offered WCBS ad libitum consumed daily on average 30 MJ ME more than those in the restricted treatments. 3.3. Cow and calf performance, dystocial cases and conception rates Housing-by-feeding interaction was not statistically significant in cow LW, LW gain (LWG), BCS and change in BCS and therefore, the main effects of housing and feeding were tested. No significant differences among the treatments were observed in the cow LW pre and post partum, pre the grazing period and post the grazing period averaging 781, 709, 688 and 733 kg, respectively (Table 3). During winter the RS and RT cows maintained their LW while the AS and AT cows gained LW (P b 0.05, − 3 vs. 41 kg). On pasture, the LWG was 61 and 32 kg (P b 0.05) for the RS and RT and for the AS and AT cows, respectively. During the entire experiment, the LWG was similar for all cows, averaging 64 kg. At calving and at the onset of the grazing period the RS and RT cows had lower BCS than the AS and AT cows, respectively (P b 0.05, 2.76 vs. 3.06; P b 0.01, 2.71 vs. 3.14). The difference between the RS and RT and the AS and AT cows tended to be significant at the

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Fig. 1. Minimum and maximum temperatures, snow depth and wind speed outdoors during the winter.

end of the grazing period (P b 0.10, 3.02 vs. 3.22). During winter the RS and RT cows lost BCS while the AS and AT cows increased BCS (P b 0.01, − 0.14 vs. 0.21). On pasture, the RS and RT cows increased their BCS more than the AS and AT cows (P b 0.05, 0.31 vs. 0.08). The change in the BCS was similar for all cows during the entire experiment, averaging 0.22. No differences were observed in claw health among the outdoor treatments. The largest sum of scores in an individual animal was 4.

The calving period was from 11 March to 21 April. Nineteen calvings occurred in March and 16 in April. In the rain-shelter areas, ten cows used the uncovered sleeping area for calving, two calved in the feeding alley, one cow was taken to the uninsulated barn and one cow calved without any detailed note of the calving place. Twelve three-wall shelter cows calved in the shelter, one cow was taken to the uninsulated barn and one cow used the nearby forest for calving. All outdoor calvings were easy. All AU cows calved inside. One AU

Fig. 2. Minimum and maximum temperatures indoors and outdoors during the winter.

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calving was classified as difficult due to faulty disposition leading to the loss of the calf, one AU calving needed slight assistance and the remaining AU calvings were easy. One AS cow pushed her newborn to the snow behind the fence and the calf died. Additionally, one RS cow did not take care of her calf, however, without loss of the calf. All other cows showed good maternal instinct towards their calves. Treatments had no effect on the calf birth weight and the LW at the age of 14 days, which averaged 43.3 and 61.2 kg, respectively (Table 4). At the age of 50 days and at the onset of the grazing period the AU calves were lighter (P b 0.05) than the AS and AT calves. The LWG of the AU calves pre the grazing period was poorer than that of the AS and AT calves (P b 0.05, 908 vs. 1186 vs. 1183 g/d). On pasture and during the entire experiment the LWG was similar for all calves, averaging 1335 and 1251 g/d, respectively. From the AS, RS, AT, RT and AU treatments 6, 7, 7, 7 and 6 cows entered the mating period. One AS cow and one AU cow entered the mating period with the experimental cows but they were not included in the calculation of the pregnancy rate since they were removed from the experiment immediately after the calf losses. One AS, one RS and one RT cow was observed to be open in the pregnancy diagnosis. The pregnancy rate was 91%.

Table 1 Mean chemical composition and feed values of experimental feeds Whole-crop Oats barley silage

Number of samples Dry matter (DM), g/kg In DM, g/kg Ash Crude protein Neutral detergent fibre Starch Lactic acid Acetic acid Butyric acid Water-soluble carbohydrates pH In total nitrogen (N), g/kg Ammonia N Soluble N D value, g/(kg DM) Feed value, /(kg DM) Metabolizable energy, MJ Amino acids absorbed in the small intestine, g

Mean S.D.

Mean

6 353

6.2

2 863

47 101 431 333 18.9 6.6 8.2 51 4.36

1.8 27 3.5 138 18.3 11.8 2.52 3.04 3.15 9.2 0.141

82 702 688

6.7 82.5 6.7

10.7 84

0.10 0.4

12.3 98

D value, digestible organic matter in DM; S.D., Standard Deviation.

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Table 2 Mean daily intake of dry matter, metabolizable energy, crude protein and amino acids absorbed in the small intestine during winter feeding period Housing

Outdoors, rain-shelter

Feeding

Ad. lib. Restricted Ad. lib. Restricted Ad. lib.

Number of 7 cows Dry matter intake, kg Whole-crop 12.14 barley silage Oats Mineral 0.057 mixture Total 12.20 Metabolizable 129.5 energy, MJ Crude protein, g 1230 Amino acids 1017 absorbed in the small intestine, g

Outdoors, three-wall shelter

Indoors

7

7

7

7

7.57

12.23

7.58

12.56

1.62 0.037

0.040

1.70 0.040

0.050

9.22 100.6

12.27 130.4

9.32 101.8

12.61 134.3

987 792

1237 1024

1000 801

1251 1052

Note: Animals were group-fed.

3.4. Blood parameters The haematological and blood chemistry values are shown in Tables 5 and 6. Housing-by-feeding interaction was statistically significant (P b 0.01) on the number of blood leukocytes only in December, when the highest number of WBCs was found in the RS and AT cows. The number of WBCs was lower (P b 0.05) in the rain-shelter cows than in the three-wall shelter cows in November. The AS and AT cows had higher (P b 0.001) number of WBCs than the RS and RT cows and the AU cows in March. All the WBCs were however, within the reference range in all animals throughout the experiment. The AS and AT cows had lower blood Hb values in the beginning of the winter (P b 0.001, November and December) and higher values at the end of the winter (P b 0.001, February; P b 0.05, March) than the RS and RT cows. This is a consequence of decreased concentrations of blood Hb values in the RS and RT cows. In spite of this, all blood Hb values remained within the reference range. The serum total protein concentrations of the AS and AT cows were lower (P b 0.001) than those of the RS and RT cows in November. The serum total protein concentrations on the ad libitum diets were lowest in the AS and highest in the AU cows in February. Furthermore, the serum total protein concentrations of

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Table 3 Live weight, live weight gain, body condition score and change in body condition score of suckler cows during winter and on pasture Significance a

Housing

Outdoors, rain-shelter

Outdoors, three-wall shelter

Indoors

Feeding

Ad lib.

Restricted

Ad lib.

Restricted

Ad lib.

Abbreviation

AS

RS

AT

RT

AU

7

7

7

7e

674 762 692 675 726

683 804 725 715 752

655 729 667 649 719

678 807 733 695 736

28.5 34.8 32.4 36.1–36.5 31.4–31.7

1 51 52

33 36 69

−6 70 64

17 41 58

2.79 2.81 2.68 2.90

2.88 3.06 3.17 3.24

2.89 2.70 2.73 3.13

− 0.11 0.22 0.11

0.29 0.07 0.36

− 0.17 0.40 0.24

Number of cows 7d Live weight, kg Initial 659 Pre calving 801 Post calving 728 Onset of grazing 707 End of grazing 735 Live weight gain, kg During winter 48 On pasture 27 Entire experiment 75 Body condition score Initial 2.99 Calving 3.05 Onset of grazing 3.11 End of grazing 3.20 Change in body condition score During winter 0.12 On pasture 0.08 Entire experiment 0.20

SEM b

P1

P2

P3

P4

P5

P6

nt c nt nt nt nt

nt nt nt nt nt

nt nt nt nt nt

18.5–19.3 12.2–12.9 12.5–13.2

nt nt nt

nt nt nt

nt nt nt

2.95 3.00 2.90 3.14

0.128 0.117 0.164–0.168 0.111–0.114

nt nt nt nt

nt nt nt nt

nt nt nt nt

− 0.05 0.24 0.19

0.110–0.116 0.110–0.118 0.087–0.091

nt nt nt

nt nt nt

nt nt nt

P7

⁎ ⁎

⁎ ⁎⁎ o ⁎⁎ ⁎

P1 = Housing-by-feeding interaction (without treatment AU). P2 = Difference between housings on ad libitum feeding (AS vs. AT vs. AU). P3 = Difference between housings on restricted feeding (RS vs. RT). P4 = Difference between housings (AS + RS vs. AT + RT). P5 = Difference between feedings in rain-shelter housing (AS vs. RS). P6 = Difference between feedings in three-wall shelter housing (AT vs. RT). P7 = Difference between feedings (AS + AT vs. RS + RT). a o P b 0.10; ⁎ P b 0.05; ⁎⁎ P b 0.01; ⁎⁎⁎ P b 0.001. b Standard error of means. c Not tested. d One cow lost her calf immediately after parturition. e One cow had a stillborn calf.

the AS and AT cows were higher (P b 0.05) than those of the RS and RT cows in February. The serum urea concentrations were lower (P b 0.05) in the rain-shelter cows than in the three-wall shelter cows in November, January and in February. The AU cows had higher (P b 0.05) serum urea concentrations than the AS and AT cows in December, January and in March. The AS and AT cows had lower serum urea concentrations than the RS and RT cows in January (P b 0.05) and in March (P b 0.001). Housing-by-feeding interaction was statistically significant on the activities of ASAT (P b 0.05) and CK (P b 0.01) in February and of ASAT (P b 0.05) in November. The activities of ASAT and CK were higher (P b 0.01) in the AS than in the RS cows in February. The activity of CK was higher (P b 0.05) in the RT than in the RS cows in February. In November, the activity of

ASAT was higher (P b 0.05) in the AT than in the RT cows. The activities of CK in December and of ASAT in January were higher (P b 0.05) in the AS and AT cows than in the RS and RT cows. Except for some individual increases in CK activity, the activities of these enzymes remained within the reference range. Housing-by-feeding interaction was statistically significant (P b 0.01) on the concentrations of LCFA only in December when the concentrations were highest in the RT and AS cows. The concentrations of LCFA were higher in the AS and RS cows than in the AT and RT cows in November (P b 0.01), January (P b 0.01) and in March (P b 0.05). The concentrations of LCFA were also higher in the AS cows than in the AT and AU cows in December (P b 0.05), January (P b 0.01) and in March (P b 0.05). The AS and AT cows had higher blood glucose concentrations than

M. Manninen et al. / Livestock Science 115 (2008) 179–194

187

Table 4 Calf live weight and live weight gain Significance a

Housing

Outdoors, rain-shelter

Outdoors, three-wall shelter

Indoors

Feeding

Ad lib.

Restricted

Ad lib.

Restricted

Ad lib.

Abbreviation

AS

RS

AT

RT

AU

Number of calves Live weight, kg At birth Day 14 Day 50 Onset of grazing End of grazing Live weight gain, g/d Pre grazing On pasture Entire experiment

7d

7

6

7

7e

45.0 64.6 111 115 244

42.9 63.0 104 111 242

43.7 60.8 108 129 250

41.5 59.1 103 118 247

43.7 58.4 91 102 219

2.45–2.83 2.77–3.15 4.6–5.1 6.4–7.1 11.0–12.4

1186 1356 1291

1179 1375 1301

1183 1278 1237

1154 1364 1278

908 1232 1102

91.6–115.5 65.9–74.2 66.3–78.1

SEM b

P1

P2

P3

⁎ ⁎

nt c nt nt nt nt

⁎

nt nt nt

P4

o

P5

P6

nt nt nt nt nt

nt nt nt nt nt

nt nt nt

nt nt nt

P7

P1 = Housing-by-feeding interaction (without treatment AU). P2 = Difference between housings on ad libitum feeding (AS vs. AT vs. AU). P3 = Difference between housings on restricted feeding (RS vs. RT). P4 = Difference between housings (AS + RS vs. AT + RT). P5 = Difference between feedings in rain-shelter housing (AS vs. RS). P6 = Difference between feedings in three-wall shelter housing (AT vs. RT). P7 = Difference between feedings (AS + AT vs. RS + RT). a o P b 0.10; ⁎ P b 0.05; ⁎⁎ P b 0.01; ⁎⁎⁎ P b 0.001. b Standard error of means. c Not tested. d One calf died immediately after parturition. e One calf died at parturition due to faulty disposition.

the RS and RT cows in November (P b 0.001) and in December (P b 0.05). Housing-by-feeding interaction was statistically significant on the serum β-HB concentrations in November (P b 0.05) and in February (P b 0.01). In November the RT cows had higher serum β-HB concentrations than the AT (P b 0.05) or the RS (P b 0.001) cows. The AS cows had higher (P b 0.001) concentrations of serum β-HB than the RS cows in February. Serum β-HB concentrations were lower in the AS and RS cows than in the AT and RT cows in December (P b 0.05) and in January (P b 0.001). In addition, the RS and RT cows had higher concentrations of serum β-HB than the AS and AT cows in December (P b 0.05) and in January (P b 0.001). Serum β-HB concentrations were higher indoors than outdoors on the ad libitum diet from November to January. These values were lower (P b 0.001) in the AT than in the AU and AS cows in February. Housing-by-feeding interaction was statistically significant (P b 0.05) on the concentrations of serum cortisol in February when the difference between the housings was found on the ad libitum diets (P b 0.01). The concentrations of serum cortisol were higher (P b 0.05) in the AT and RT cows than in the AS and RS cows in

November. The AS and AT cows had higher (P b 0.001) cortisol values than the RS and RT cows in March. Except for very few increased sporadic values, serum cortisol concentrations were low throughout the experiment. Housing-by-feeding interaction was statistically significant (P b 0.05) on the concentrations of serum leptin in January when they were higher in the AT than in the RT cows. 4. Discussion 4.1. Climatic conditions and winter housing facilities The harsh winter in Finland does not seem to be a particular obstacle for keeping suckler cows in outdoor housing facilities although the weather conditions vary greatly geographically. The winter conditions at our experimental station are arctic-continental in nature. The wind conditions are dualistic. South-West winds are usually milder than North-East winds during the winter. In the present experiment the wooden wind breaks were built against the North-East winds but the wind speed exceeded 5 m/s only occasionally. The outdoor pens were built in the forest area but the forest as a wind break was

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M. Manninen et al. / Livestock Science 115 (2008) 179–194

of minor importance due to mild winds. In general, wind breaks can be considered as a desirable provision for outdoor areas. The wind breaks with a 3-cm space between boards used in our study proved to offer an

adequate barrier to winds which is in good accordance with the results of Moysey and McPherson (1966) who reported that a 20% porosity fence gave better protection against snow and wind than a solid fence. Christopherson

Table 5 Haematological values and serum constituents of suckler cows during winter Significance a

Housing

Outdoors, rain-shelter

Outdoors, three-wall shelter

Indoors

Feeding

Ad lib.

Restricted

Ad lib.

Restricted

Ad lib.

Abbreviation

AS

RS

AT

RT

AU

7

7

7

7

8.7 9.1 7.3 7.1 6.9

9.2 9.2 7.7 7.8 7.7

10.2 7.1 7.1 6.6 6.1

9.3 8.0 8.3 7.1 6.4

0.51 0.58 0.46 0.54 0.31

147 139 128 109 121

129 121 119 128 130

144 134 125 113 124

133 129 124 126 131

2.3 2.7 3.5 3.5 3.4

76 75 72 69 71

72 74 75 76 73

74 73 70 70 73

73 75 77 79 75

0.9 1.1 1.6 1.7 1.2

3.4 3.0 3.3 3.0 3.4

3.7 3.2 3.2 3.1 2.3

4.3 3.0 3.8 3.8 3.4

4.2 4.0 3.7 3.6 2.9

0.25 0.25 0.25 0.25 0.25

72 65 59 55 62

76 72 62 60 65

62 56 53 61 71

63 70 63 60 64

3.9 4.7 3.4 2.3 3.0

217 87 97 73 102

123 151 98 94 134

157 91 86 107 120

94 116 110 98 105

na d na na na na

Number of cows 7 Leukocyte, ×10 9/l November 8.6 December 8.0 January 8.0 February 7.9 March 7.5 Haemoglobin, g/l November 125 December 127 January 126 February 127 March 129 Total protein, g/l November 71 December 73 January 74 February 72 March 71 Urea, mmol/l November 3.4 December 3.0 January 2.6 February 2.9 March 2.0 Aspartate aminotransferase, U/l November 69 December 68 January 66 February 66 March 64 Creatine kinase, U/l November 122 December 117 January 113 February 123 March 115

P1 = Housing-by-feeding interaction (without treatment AU). P2 = Difference between housings on ad libitum feeding (AS vs. AT vs. AU). P3 = Difference between housings on restricted feeding (RS vs. RT). P4 = Difference between housings (AS + RS vs. AT + RT). P5 = Difference between feedings in rain-shelter housing (AS vs. RS). P6 = Difference between feedings in three-wall shelter housing (AT vs. RT). P7 = Difference between feedings (AS + AT vs. RS + RT). a o P b 0.10; ⁎ P b 0.05; ⁎⁎ P b 0.01; ⁎⁎⁎ P b 0.001. b Standard error of means. c Not tested. d Not available.

SEM b

P1

P2

P3

P4

P5

P6

⁎ nt

nt

⁎⁎

nt c ⁎ nt nt nt

nt nt nt

nt ⁎ nt nt nt

nt nt nt nt nt

nt nt nt nt nt

⁎⁎⁎ ⁎⁎⁎

nt nt nt nt nt

nt nt nt nt nt

⁎⁎⁎

nt nt nt nt nt

nt nt nt nt nt

⁎⁎

o

o ⁎ o o ⁎ ⁎ ⁎ ⁎ ⁎

⁎⁎

o

nt nt nt nt nt

o

nt nt nt nt nt nt nt nt nt nt

⁎

o nt nt o nt

nt

nt nt nt ⁎ nt

⁎ ⁎

nt

nt

nt nt ⁎⁎ nt nt nt nt ⁎⁎ nt

⁎ nt nt

P7

nt o ⁎⁎⁎

⁎⁎⁎ ⁎

o ⁎

⁎ ⁎⁎⁎ nt o ⁎ nt

nt nt nt nt

o ⁎ nt

nt

M. Manninen et al. / Livestock Science 115 (2008) 179–194

189

Table 6 Serum and blood constituents of suckler cows during winter Significance a

Housing

Outdoors, rainshelter

Outdoors, three-wall shelter

Indoors

Feeding

Ad lib.

Restricted

Ad lib.

Restricted

Ad lib.

Abbreviation

AS

RS

AT

RT

AU

7

7

7

0.14 0.11 0.14 0.30 0.28

0.16 0.16 0.19 0.37 0.33

0.11 0.10 0.10 0.18 0.25

0.032 0.014 0.032 0.044 0.056

2.5 2.3 2.6 2.4 2.1

2.1 2.1 2.6 2.7 2.2

2.5 2.0 2.6 2.3 1.9

0.14 0.14 0.14 0.14 0.14

0.24 0.35 0.38 0.18 0.25

0.35 0.39 0.49 0.19 0.24

0.37 0.46 0.48 0.28 0.23

na d na na na na

29 25 16 17 26

38 30 16 8 13

16 15 17 36 14

na na na na na

4.0 4.1 4.4 4.1 3.4

3.6 3.5 3.1 3.0 2.9

4.5 4.5 4.3 4.3 3.8

0.30 0.30 0.30 0.30 0.30

Number of cows 7 7 Long-chain fatty acids, mmol/l November 0.22 0.26 December 0.15 0.12 January 0.25 0.27 February 0.21 0.30 March 0.48 0.43 Glucose, mmol/l November 2.7 1.9 December 2.3 2.0 January 2.7 2.7 February 2.5 2.6 March 2.2 2.2 β-hydroxybutyrate acid, mmol/l November 0.20 0.18 December 0.24 0.34 January 0.22 0.35 February 0.32 0.18 March 0.23 0.24 Cortisol, nmol/l November 13 23 December 18 26 January 18 12 February 9 14 March 30 7 Leptin, μg/l November 3.8 3.4 December 3.9 3.6 January 3.8 3.7 February 3.6 3.5 March 3.2 2.7

SEM b

P1

P2

P3

P4

P5

P6

⁎⁎

o ⁎ ⁎⁎

nt c ⁎ nt nt nt

⁎⁎ nt ⁎⁎ o ⁎

nt nt nt nt

nt ⁎ nt nt nt

nt nt nt nt nt

nt nt nt nt nt

⁎⁎⁎ ⁎

⁎ nt nt

nt ⁎ ⁎⁎⁎ nt

⁎

nt nt nt nt nt ⁎ ⁎⁎

⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎ ⁎⁎⁎

⁎⁎⁎ nt nt

nt ⁎ ⁎⁎⁎ nt

nt

⁎

⁎

⁎⁎

nt nt nt

⁎

nt nt ⁎⁎⁎ nt nt nt nt

nt nt

nt

nt nt

nt nt nt

nt nt

nt nt

P7

nt o

nt nt nt nt o nt

nt ⁎⁎⁎

nt nt ⁎⁎ nt nt

nt o o

P1 = Housing-by-feeding interaction (without treatment AU). P2 = Difference between housings on ad libitum feeding (AS vs. AT vs. AU). P3 = Difference between housings on restricted feeding (RS vs. RT). P4 = Difference between housings (AS + RS vs. AT + RT). P5 = Difference between feedings in rain-shelter housing (AS vs. RS). P6 = Difference between feedings in three-wall shelter housing (AT vs. RT). P7 = Difference between feedings (AS + AT vs. RS + RT). a o P b 0.10; ⁎ P b 0.05; ⁎⁎ P b 0.01; ⁎⁎⁎ P b 0.001. b Standard error of means. c Not tested. d Not available.

(1985) states that wind breaks result in a considerable saving of feed during cold weather. During the winter months when the wind speed is 15 km/h (=4.2 m/s) and the outdoor temperature averages −10 °C to−15 °C a wind break will reduce feed requirements of feedlot cattle by approximately 10.5 MJ ME/d (Christopherson, 1985). Contradictorily, McCarrick and Drennan (1972a,b) showed there is no advantage in providing wind or overhead shelter for growing cattle. In regions with

moderate winter temperatures, but frequent wet periods, the value of wind breaks may be questionable since they may retard the rate of evaporation from the area and result in persistently muddy conditions which are stressful for cattle (Christopherson, 1985). The cows mainly used the sheds and shelters, laying and feeding areas and moved mainly along cow paths through the snow in our study, during the winter. After the snow had melted, the calves and consequently the cows

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M. Manninen et al. / Livestock Science 115 (2008) 179–194

also used the farthest parts of the outdoor area. There were uncovered sleeping areas also in the AT and RT pens but the cows did not use them since they had a three-wall shelter area where the bedding was always dry. In general, the cold tolerance of cattle is based upon a great variety of adaptation reactions. The cows seek shelter or weatherprotected areas, avoid lying in the cold, increase feed intake, orient themselves to present the least area to the wind, shiver and above all, develop subcutaneous fat cover and a winter hair coat during the autumn ready for the winter period (Wassmuth et al., 1999). Only one calf was lost due to the somewhat deficient outdoor facilities. Some calf losses were avoided by careful supervision by the technical staff. Therefore, it may be worth arranging for the calving period to occur after the coldest months to reduce the risks rising from cold weather (Young, 1983) or to organize as compact calving periods as possible. In our study, all the animals were clean during the entire winter period. The cows outdoors were dry or snowy on approximately 87% of the observed days and the wet ratings were recorded mainly in the autumn. It is important to maintain the cow's coat dry and clean. Wet and muddy cows combined with exposure to open wind increase the energy requirement and need for higher feed intake (Ames, 1987), and moisture and wind considerably reduce the effective thermal insulation of the animal's coat (Young, 1983). 4.2. Feeds and feeding In the outdoor housing facilities feeding occurred without difficulties, also during the coldest periods and in the ad libitum treatments. Due to the high DM content the WCBS did not freeze. The WCBS was of average fermentation quality except the amount of butyric acid was rather high. The concentration of starch was rather high compared to the values reported by Manninen et al. (2005), suggesting that the WCBS probably was at the late dough stage of maturity approaching to the yellow ripening stage. The energy content of the WCBS, based on the in vitro measurements, averaged 10.7 MJ ME/kg DM and was higher than the 9.4 MJ ME/kg DM, evaluated prior to the experiment based on the chemical composition. Due to the underestimation of the energy value of WCBS the feed portions in the restricted treatments were too high. Thus, the daily energy intake on the RS and RT diets averaged 101.2 MJ ME. That amount of energy was slightly higher than Manninen et al. (2004) used for adult Hf cows of the same body size (87.5 MJ ME, in vivo measured) and slightly lower than Manninen

et al. (2005) offered to adult Hf cows in outdoor feeding (109.2 MJ ME, in vivo measured). Taking a reliable feed sample from WCBS may be difficult. An unrepresentative feed sample may give an over- or underestimated energy value which may lead to erroneous feed amounts in the restricted feeding scheme. In the present study the protein intake, expressed as AAT, was restricted in the RS and RT treatments but exceeded the recommendations (MTT, 2004) for dairy cows. On the basis of the results observed in our earlier studies and in the present study, the amount of energy might have been approximately 15% lower than now offered without any detrimental effects on cow performance. In the present experiment, during the entire winter period a cow on the ad libitum diet consumed on average 6360 MJ ME more than a cow on the restricted diet. Roughages with high or even moderate digestibility, e.g. grass silage or WCBS, if offered ad libitum to suckler cows in good BCS at housing, may be uneconomical and unenvironmental feeds since the cows consume such feeds too much leading to excessively high BCS and therefore, waste of energy and nutrients. Therefore, feeds having rather low energy content are probably more suitable for an ad libitum winter feeding strategy for suckler cows in good BCS at housing than feeds with a high-energy content. The higher pre grazing cow BCS on ad libitum diet outdoors (3.14) compared with restricted diet outdoors (2.71) suggests that the restricted feeding was at least sufficient for the mature beef breed cows. One possible explanation for the good pre grazing BCS even on restricted diet may be the unsuitability of dairy cow feeding recommendation for suckler cows. In our study the WCBS ad libitum intake did not differ among the housing facilities. In fact, the DM intake on the ad libitum diet indoors was numerically slightly higher compared to those measured outdoors. Cold usually stimulates the appetite and the increase has been assumed to reflect the increase in the metabolic demands. When animals are subjected to extreme cold stress, substantial dietary energy may be diverted from productive functions to the generation of body heat and cold stress may lead to the development of secondary changes and possibly disease (Young, 1983). Experiments (e.g. Kennedy et al., 1976, 1977; Gonyou et al., 1979) have shown that when ruminants are exposed to cold, there is also an increase in rumination activity, reticulorumen motility and rate of passage of digesta as well as a reduction in the volume of the reticulorumen. A consequence of these changes is a reduction in digestion in the reticulorumen, particularly with roughages and associated with an increased rate of passage of digesta which results in reduced digestive efficiency

M. Manninen et al. / Livestock Science 115 (2008) 179–194

(Young, 1981). In the present study, the mature, pregnant Hf cows were not in extremely harsh winter conditions even in the AS and RS treatments, and the differences in climatic conditions among the winter housing facilities were rather small. 4.3. Animal performance In the present experiment, the treatments had no effect on the cow LW. Only small effects on the cow BCS during the winter period were observed. During winter the LWG was positive for all cows except for those in the RT treatment. The LW loss in the RT treatment, on average 6 kg, was marginal suggesting that all cows maintained their LW during the winter period. However, the initial LW of the cows was measured in mid-gestation which have to be considered and therefore, the LW change includes the weight of fetus. This slightly positive LWG during winter is in accordance with the common statement that beef cows are usually fed over winter to maintain weight or to allow some small loss in body weight (Young, 1981). Earlier studies in Canada (e.g. Jordan et al., 1968; Hironaka and Peters, 1969; Lister et al., 1972) have reported that the maintenance energy requirements for over-wintering beef cows increase by 30 to 70% due to adverse climatic conditions. The cow performance results observed in our study do not support this statement, probably mainly due to the differences in climatic conditions between Canada and Finland where, in spite of the cold days, the winter conditions are milder without harsh winds. The cow BCS was good at every evaluation point, especially at calving and at turnout, exceeding the recommended value stated by Lowman et al. (1976). In agreement with our results, Wassmuth et al. (1999) observed outdoor-wintered suckler cows to have BSCs at the end of the winter similar to those of indoor cows, suggesting that the expected increase in basal metabolic rate was not high. The good BCS values in the present study best explain the acceptable conception rates. There is no specific interpretation for the three cows observed to be open after the mating period. At the end of the grazing period the cows were on average 64 kg heavier than at the beginning of the winter period. The positive LWG and change in BCS on pasture indicate a sufficient pasture area and good grass quality. The calf LWG was quite similar in all treatments and only small differences among the treatments were observed pre the grazing period. No particular explanation can be given for the lower LWG pre the grazing period indoors but probably the indoor conditions were not as favorable as the outdoor conditions. However, the

191

calf LW and LWG observed in the present study were very similar to the values reported by Manninen et al. (2004, 2005, 2006) with the same type of animals in the same pre grazing and grazing conditions. The satisfactory LWG of the calves suggests good milk production capacity of the cows and thus, the availability of sufficient energy for the cows. Kubisch et al. (1991) reported that weaned bull calves with shelter had a higher rate of gain compared to those with no shelter but the difference was restricted to the coldest periods. The effects of cold stress on the beef cow appear to be primarily on the energy requirement for maintenance, as pregnancy, development of the conceptus and, consequently, calf birth weight are unaffected (e.g. Wiltbank et al., 1962; Jordan et al., 1968; Hironaka and Peters, 1969). This statement is supported by the results observed in this study. In addition to many other environmental, nutritional, physiological and hereditary factors, it has been suggested that an extremely cold environment might cause subclinical laminitis (Vermunt, 1990). In this study there were several cold periods but very few changes in the claws were observed. Lameness is generally thought to be associated with intensive management and nutrition (Greenough, 1997) and not so much with extensive suckler cows. Subclinical laminitis causes overgrowth of the claw and haemorrhages in the sole and is presumed to be an important predisposing factor to other claw diseases like white line rupture (Bergsten, 1995). It has been hypothesised that cold temperatures would cause physiological changes on claw blood circulation that would cause the changes of subclinical laminitis (Vermunt, 1990). Hard surfaces increase the incidence of laminitis and white line rupture in dairy cows (Rowlands et al., 1983; Colam-Ainsworth et al., 1989). In our study, none of the outdoor surfaces were extremely hard. Motion has a beneficial effect on claw health, probably due to better blood flow (Gustafson, 1993) which can be one reason for the good claw health in this study. In the present experiment the number of animals per treatment and the climatic differences among the housings were quite small which should be taken into account when interpreting e.g. the fertility, incidence of dystocia and claw health results. 4.4. Blood parameters The clearest differences among the treatments were seen in the values for LCFA, urea, β-HB and Hb. Lipolysis, due to e.g. a low-energy diet, increases the LCFA concentrations in cattle (Reid et al., 1977;

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M. Manninen et al. / Livestock Science 115 (2008) 179–194

DiMarco et al., 1981). The differences in concentrations of LCFA among the treatments could have reflected the environment, suggesting that in cold circumstances, particularly in animals in rain-shelter groups, some activation of lipolysis occurred. However, this activation was rather small and no clear effects on the feed intake, LW or BCS could be observed. The differences in urea and β-HB concentrations among the treatments are interesting. Roughly speaking they seem to be fairly parallel during the winter which means that the highest values were in the treatment AU, then in the AT and RT treatments, with the lowest values in cows in the harshest conditions, in the AS and RS treatments. As mentioned earlier, cold exposure has been reported to increase reticulorumen motility (Kennedy et al., 1976, 1977; Gonyou et al., 1979) and reduce digestive efficiency (Young, 1981). Butyrate is metabolized to β-HB in the rumen epithelium and surplus ammonia from the rumen and intestine is a source for urea synthesis in the liver. One explanation for these differences in β-HB and urea concentrations among the treatments could be different environmental circumstances which may have been reflected in the digestive functions. However, no β-HB values N 1 mmol/l, indicating mildly ketotic cows (Gröhn et al., 1983), were measured in the present experiment. The decrease of Hb concentrations of cows on restricted diet is difficult to explain. This phenomenon could be due to smaller amounts of consumed protein (Payne and Payne, 1987), but the concentrations of serum protein and urea do not support this theory. Serum concentrations of leptin have been found to correlate with fat reserves in many animals including sheep and cows (Blache et al., 2000; Erhardt et al., 2000). When the changes in LW or BCS were rather small, only minor changes in the adiposity of the animals seem to have occurred and reflected in the leptin values. The secretion of cortisol can increase during extraordinary stress (e.g. Rijnberk and Mol, 1997), and ASAT and CK are released into the blood at times of muscular stress and disorders (Cardinet, 1997). Except for sporadic increases in cortisol and CK in very few animals in different treatments, the values of these parameters remained at a low level. Therefore we can conclude that the treatments caused neither aggressive behaviour resulting in muscle injuries or clearly increased motility, nor strong stress. Although cows usually respond poorly to mild inflammations by increasing their WBC (Taylor, 2000), the lack of high values in this study suggests that no severe inflammations occurred. The observations of the animals confirm this interpretation.

5. Conclusions All winter housing facilities offered adequate shelter for mature, pregnant suckler cows and had only minor effects on the cow and calf performance without any practical importance. None of the treatments caused any clear disturbances to the animals' welfare. No signs of extraordinary stress, massive consumption of energy stores, claw problems, frequent muscle injuries or severe inflammations could be observed. The outdoor conditions seem to have some small effects on lipid metabolism. In outdoor winter housing facilities in cold conditions careful management of the animals, especially during the calving season, is important to avoid calf losses. Whole-crop barley silage offered in restricted amount gave enough energy for the cows during the winter period. Acknowledgements The authors are indebted to Mrs. Ulla Eronen and her staff for technical assistance during the experiment. Special thanks are due to Juha Hurmalainen, DVM, for his cooperation with the blood sampling programme. The vitamin mixture used in the present experiment was provided by Hiven Ltd., which is gratefully acknowledged. The evaluation of the manuscript by Dr. Seija Jaakkola is also gratefully acknowledged. References Ames, D.R., 1987. Effects of cold environments on cattle. Agri-Pract. 8, 26–29. Bach Knudsen, K.E., Åman, P., Eggum, P.O., 1987. Nutritive value of Danish grown barley varieties. I. Carbohydrates and other major constituents. J. Cereal Sci. 6, 173–186. Bergsten, C., 1993. A photometric method for recording hoof diseases in cattle, with special reference to haemorrhages of the sole. Acta Vet. Scand. 34, 281–286. Bergsten, C., 1995. Digital disorders in dairy cattle with special reference to laminitis and heel horn erosion: The influence of housing, management and nutrition. Dissertation. Skara. Sweden. Swedish University of Agricultural Sciences, pp. 35–38. Birkelo, C.P., Johnson, D.E., Phetteplace, H.P., 1991. Maintenance requirements of beef cattle as affected by season on different planes of nutrition. J. Anim. Sci. 69, 1214–1222. Blache, D., Tellam, R.J., Chagas, L.M., Blackberry, M.A., Vercoe, P. E., Martin, G.B., 2000. Level of nutrition affects leptin concentrations in plasma and cerebrospinal fluid in sheep. J. Endocrinol. 165, 625–637. Cardinet III, H.C., 1997. Skeletal muscle function, In: Kaneko, J.J., Harvey, J.W., Bruss, M.L. (Eds.), Clinical Biochemistry of Domestic Animals, 5th ed. Acad. Press, San Diego, USA, pp. 407–440. Christopherson, R.J., 1985. Management and housing of animals in cold environments. In: Yousef, M.K. (Ed.), Stress Physiology in Livestock. Ungulates, vol. II. CRC Press, Inc., Boca Raton, Florida, USA, pp. 175–194.

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