The effect of breed and housing system on dairy cow feeding and lying behaviour

In Ireland there is growing interest in managing dairy cows on out-wintering pads (OWPs) during the winter, as a low cost alternative to housing indoors. This study investigated feeding and lying behaviour of two breeds of dairy cow (Holstein-Friesian and Norwegian Red) at pasture (PAS) and in winter (WIN) confinement. Cows (n = 36) were managed as one herd while lactating at PAS, then dried off on entering WIN on 17 November 2005 and assigned to one of the three treatments using a randomised complete block design: (1) indoor matted cubicles [IC], (2) unsheltered OWP [UP] and (3) sheltered OWP [CP] (feed system = concrete feedface). Feeding behaviour was recorded for 1 × 24 h period during PAS and WIN using IGER grazing behaviour recorders. Standing/lying was recorded every 5 min for 2 × 24 h periods at PAS and 1 × 24 h period during WIN using modified voltage dataloggers (Tinytag Plus, Chichester, UK). Although not compared statistically, cows spent more time feeding at PAS (530.7 ± 69.66 min/day) than in any winter confinement system (UP, IC, CP = 453.9 ± 37.36, IC = 462.7 ± 37.31 and CP = 505.9 ± 37.36 min/day). In contrast, cows spent more time lying during the winter period (UP, IC, CP = 11.7 ± 0.45, IC = 10.8 ± 0.39 and CP = 11.0 ± 0.39 h/day) than when at PAS (9.4 h/day). Holstein-Friesian cows had a higher bite rate and fewer mastications while feeding, than Norwegian Red cows (P < 0.05 for both). Shorter feeding times at WIN were likely primarily due to lower metabolic requirements associated with the dry period, although the higher fibre content of the silage may also have contributed. The increase in ruminating times between PAS and WIN is likely also due to the higher fibre content of silage than grass. Differences in feeding behaviour between breeds may be indicative of reduced motivation to ingest food quickly. This may be an indirect consequence of a selection index that has led to improvements in body condition and self-maintenance. The similarity in lying and feeding times during WIN indicates that during these winter weather conditions the feeding and lying behaviour of cows on unsheltered OWPs was not inhibited compared with sheltered cows.     

Impact of lameness on gait characteristics and lying behaviour of zero grazed dairy cattle in early lactation

The present study examines the impact of lameness on the time budgets and gait of dairy cattle during early lactation. Automated assessment of activity together with an objective method (using video motion analysis) of assessing the gait of the cattle was utilised.Twenty-five Holstein dairy cows were recruited to the study and were assessed during weeks 1, 6 and 12 of lactation. Lying behaviour was measured using IceTag? activity monitors which were attached to the right hind leg of the cow for 4 consecutive days during each study week. Cows were locomotion scored to evaluate the influence of lameness on gait and behaviour of cows. Cows that were lame in a hind limb had significantly shorter fore and hind stride lengths. They also tended (p = 0.06) to have a negative tracking distance and walk at a slower (p = 0.002) speed compared with cows that were considered to be non-lame. Lame cows spent 2 h more time lying down per day in comparison to non-lame cows. Cows spent significantly less time lying down during week 6 of lactation and more time standing in comparison to the cows in week 12. The lying behaviour of cows was not different during weeks 1 and 6 or weeks 1 and 12. Cows were significantly more active during week 1 than week 12 of lactation. However the activity of the cows during week 6 was not different from weeks 1 and 12 of lactation. The present study demonstrates that lameness influences stride characteristics and lying behaviour of zero grazed dairy cows.     

Behavioural responses of sows and piglets from two genotypes to recorded nursing grunts played throughout lactation

The impact of playbacks of recorded sow nursing grunts on the development of nursing behaviour in sows from two genotypes was studied. Yorkshire × Landrace (YL; n = 16) and 25% Meishan (MH; n = 16) gilts were equally divided in two groups: (1) no playback, and (2) playbacks of recorded sow nursing grunts at 35-min intervals. Recordings were played from day 110 of gestation until day 27 of lactation. Sow behaviour was videotaped for 24 h every 4 days, from days 6 to 26 of lactation. Playbacks decreased nursing intervals in MH (34.9 min versus 38.2 ± 1.1 min) without altering it in YL (37.9 min versus 36.5 ± 1.1 min; breed × treatment, P < 0.05), although this effect in MH was likely due to the increased frequency of non-productive nursings seen on days 6, 10 and 14 (P < 0.05) in sows subjected to playbacks. In both breeds, the interval between nursings increased (P < 0.01) from day 6 (33.7 ± 0.8 min) to 26 (40.8 ± 0.8 min) of lactation, the interval between non-productive nursings (NPN) remained similar (P > 0.1) and sows, compared to piglets within a litter, ended more nursings as lactation advanced (P < 0.01). More nursings were terminated by sows in MH than in YL (P < 0.01) whereas more nursings were terminated by piglets from YL than MH sows (P < 0.05). Playbacks or genotype did not alter the amount of time over a 24 h period that sows spent standing, sitting, lying on the belly or lying with the udder exposed (P > 0.1), but sows spent more time sitting, standing and lying on the belly and less time lying with the udder exposed as lactation advanced (P < 0.01). Posture changes were more frequent for MH than YL sows (P < 0.01) and increased as lactation advanced in both genotypes (P < 0.01). In conclusion, the effects of playbacks on nursing behaviour differed between genotypes: playbacks decreased nursing intervals in MH sows only, although this was likely due to an increase in NPN.     

Effects of dietary conjugated linoleic acid on metabolic status,BW and expression of genes related to lipid metabolism in adipose tissue of dairy cows during peripartum

Conjugated linoleic acid (CLA) dietary supplementation reduces milk fat content and yield, but its effects on lipid metabolism and energy status remain controversial. The objective of this study was to investigate the effects of dietary CLA on adipose tissue (AT) mRNA abundance of genes related to lipid metabolism, plasma indicators of metabolic status, body condition score (BCS) and BW changes in dairy cows. Sixteen multiparous Holstein cows (3.2 ± 1.4 lactations, 615 ± 15 kg BW) were randomly assigned to treatments: 1) CLA; rumen-protected CLA (75 g/d) or 2) Control; equivalent amount of rumen inert fatty acid (FA) as the previous diet (78 g/d), from − 20.2 ± 3.2 (mean ± SEM) to 21 d relative to calving (d 0). Subcutaneous AT was biopsied from the tail-head region at d 21 to determine the mRNA abundance of genes related to lipid metabolism. Blood samples were collected at − 20.2 ± 3.2, 0, 7, 14 and 21 d relative to calving to determine plasma non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), insulin and glucose. Conjugated linoleic acid decreased milk fat yield and milk fat content by 15 and 16%, respectively. Cows fed CLA had lower plasma NEFA and BHBA and greater glucose and insulin concentrations (P < 0.05). Mean BCS at 21 d postpartum was greater (P < 0.01; 2.89 vs 2.25), and BCS loss from the day of enrollment to 21 d postpartum was reduced (P < 0.01; − 0.13 vs − 0.64) in the CLA group. The expression of acylcoenzyme A oxidase, carnitine palmitoyltransferase 1A, hormone-sensitive lipase, β2 adrenergic receptor and acetyl-CoA carboxylase was downregulated by CLA supplementation, whereas the expression of sterol regulatory element binding protein, lipoprotein lipase and peroxisome proliferator-activated receptor gamma was upregulated (P < 0.01). In summary, CLA-supplemented cows showed signs of better metabolic status and less severe fat mobilization. Moreover, CLA increased mRNA abundance of genes related to lipogenesis and decreased mRNA abundance of genes related to FA oxidation and lipolysis in the AT of dairy cows during early lactation.     

The influence of dry period feeding on liver fat and postpartum performance of dairy cows

Animal performances were monitored in 30 Friesean dry cows (18 multiparous, MP-cows and 12 primiparous, PP-cows) starting six weeks before calving to eight weeks after calving. The cows were kept indoors and fed individually with a prepartum diet containing either low, moderate or high energy (0.75, 1.00 or 1.25 of the calculated ME requirement) and supplemented with low (0.3 kg day⁻¹) or high (1.5 kg day⁻¹) rapeseed meal (RSM). The diets were consisted of 1.5 kg hay, 20–25 kg wilted grass silage and grain (barley and oat, 1 : 1 DM basis) with RSM. The average ME intake during six weeks of prepartum was 75, 97 and 123 MJ day⁻¹ on three different energy levels. After calving the cows were fed grass silage ad lib, 6.5 kg (primiparous) or 8.5 kg (multiparous) grain and 1.5 kg RSM. Liver biopsy and blood samples were taken to determine differences in metabolites due to diet and parity. Reduction of prepartum energy allowance to 0.75 of the moderate level did not affect the calf's birth weight and colostrum composition. Cows fed prepartum low energy–high rapeseed meal diet (LEHR) showed a faster increase in feed intake and milk production after parturition. Continuous low feed intake and milk production were observed in cows fed a prepartum high energy–low rapeseed meal diet (HELR). Milk yield was constantly lower for cows fed prepartum high energy diet, the difference being significant (p<0.01 and p<0.05) at six and seven weeks of lactation. Overall milk yield also showed a linear decrease with energy feeding level and an increase (p<0.10) with RSM feeding levels. Prepartum high energy feeding increased (p<0.01) milk protein content. Neither energy nor RSM feeding level affected the liver fat infiltration of the experimental cows. Cow parity however showed a significant influence on liver fat content, β-hydroxybutyrate (BHBA) and plasma glucose. A week before calving, the plasma concentration of essential amino acids (EAA) was lower for cows fed prepartum low energy diet. During the first four weeks of lactation, the concentrations of plasma non-esterified fatty acids (NEFA) and insulin were similar for all the treatment group.     

Feeding behaviour and activity as early indicators of disease in pre-weaned dairy calves

Across the industry, there is large variation in health status of dairy calves and as a result, disease incidence and antibiotic use is high. This has significant implications for animal welfare, productivity and profitability of dairy and dairy-beef production systems. Technology-based early detection systems could alleviate these issues; however, methods of early detection of disease in dairy calves have not been widely explored. This study aimed to determine whether changes in activity and feeding behaviour can be used as early warning indicators of respiratory disease in calves. In total, 100 pre-weaned male Holstein calves (age: ~ 8−42 days) were used. Calves were group-housed and provided with starter diet, straw bedding and ad libitum water. Calves were fed milk replacer ad libitum through an automatic calf feeder, and each calf was fitted with a leg-mounted activity monitor. Daily activity and feeding behaviour variables were calculated for each calf. Each calf was assessed daily using a modified version of the Wisconsin Scoring System to assess respiratory disease status. Calves were classed as ‘Diseased’, ‘Intermediate’ or ‘Healthy’ based on their cumulative health score. The peak day of the most extreme illness event was identified for each calf. Data from Diseased and Healthy calves were paired for analysis based on age and BW. Data were compared for the day of peak illness, and for the 3 days previous and post. Compared to healthy calves, diseased calves lay for longer and tended to have longer lying bouts (daily lying: 17.6 ± 0.3 vs 16.7 ± 0.2 h, P < 0.01; bout length: 74.8 ± 10.6 vs 56.0 ± 3.7 min, P = 0.09 for diseased and healthy calves, respectively). Diseased calves fed for a shorter time and had fewer feeder visits (with intake) each day compared to healthy calves (feeding time (min): 19.3 ± 1.4 vs 22.8 ± 1.5; P < 0.05; visits: 2.1 ± 0.2 vs 3.2 ± 0.4; P < 0.05). Importantly, differences between diseased and healthy calves were evident in both activity and feeding behaviour on the days prior to the peak day of disease. Lying bout length was greater in diseased calves for the 2 days prior to the peak day (P < 0.05), lying time was longer on day − 1 (P < 0.05) and feeder visits with milk intake were less frequent on day − 3 (P < 0.05). Thus, measurement of feeding and activity using precision technology within early detection systems could facilitate early intervention and optimized treatment.     

Biochemical changes in the follicular fluid of the dominant follicle of high producing dairy cows exposed to heat stress early post-partum

High yielding dairy cows experience a negative energy balance (NEB) early post-partum and it was hypothesized that this may be aggravated under summer heat stress (HS) conditions. In this study, which was performed in Egypt, 20 Holstein cows were followed during summer (n = 10) and winter (n = 10) seasons. All cows were multiparous and kept at the same herd. Blood was sampled from each cow starting 1 week before the expected calving date and then at 1-week intervals until week 6 post-partum. From week 2 to 6 post-partum follicular fluid was collected through transvaginal follicular fluid aspiration at 6 days intervals. Ambient air temperature (AT) and relative humidity (RH) were recorded and temperature–humidity index (THI) was calculated as well. Respiration rate (RR), rectal temperature (RT), and body condition score (BCS) were recorded for each cow at the time of blood sampling. Concentrations of glucose, insulin like growth factor-1 (IGF-1), non-esterified fatty acids (NEFA), urea and total cholesterol (TC) were measured in each blood and follicular fluid sample. All the cows showed a significantly higher RR and RT in summer (95.5 ± 1.1 and 39.88 ± 0.06, respectively) than in winter (43.89 ± 0.61 and 38.94 ± 0.07, respectively) (P < 0.001). Body condition score loss during the early post-partum period was higher in summer than in winter (1.1 ± 0.07 vs. 0.85 ± 0.06 point, respectively) (P < 0.001). The average dominant follicle diameter was significantly lower in summer than in winter during the period of negative energy balance (11.6 ± 0.7 mm vs. 15.3 ± 1.2 mm, respectively) (P < 0.01). Under summer heat stress, the concentrations of glucose (2.98 ± 0.07 and 2.19 ± 0.04 mmol/L), IGF-1 (106.7 ± 2.9 and 99.0 ± 3.4 ng/ml) and TC (137.3 ± 5.3 and 62.2 ± 5.1 mg/dl) in blood and FF, respectively, were significantly lower than winter concentrations by (0.17 ± 0.03 mmol/L, P < 0.001 and 0.26 ± 0.06 mmol/L, P < 0.001), (12.3 ± 3.6 ng/ml, P < 0.001 and 9.0 ± 2.7 ng/ml, P < 0.001) and (20.7 ± 1.8 mg/dl, P < 0.001 and 7.3 ± 1.1 mg/dl, P < 0.01), respectively. However, the concentrations of NEFA (0.68 ± 0.14 and 0.22 ± 0.02 mmol/L) and urea (9.27 ± 0.34 and 9.96 ± 0.25 mmol/L) in blood and FF, respectively, were significantly higher in summer compared to winter (0.50 ± 0.08 mmol/L, P < 0.001 and 0.20 ± 0.02 mmol/L, P < 0.001) and (8.77 ± 0.23 mmol/L, P < 0.05 and 8.96 ± 0.29 mmol/L, P < 0.001), respectively, throughout the experimental period. The results of the present study indicate that heat stress early post-partum aggravates NEB in high yielding dairy cows, reduces BCS, dominant follicle diameter and alters the biochemical concentrations in the follicular fluid of the dominant follicle which may result in inferior oocyte and granulosa cell quality and hence poorer fertility.     

Effect of short and long periods of separation on agonistic behaviour,injuries and stress in Hérens cows kept in loose housing

Hérens cows are typically not dehorned and are therefore housed in tie-barns during winter. Recently, however, farmers have started to also use loose housing systems. They separate single cows from their herd for periods of a few days to ensure undisturbed calving and to avoid excessive activity caused by animals in oestrus. As these cows are highly motivated to fight, the re-introduction of individuals after separation is usually associated with increased agonistic behaviour. The aim of this study was to compare the effects of the length of separation with regard to behaviour, injuries and stress response.The study was conducted with 45 focal horned Hérens cows kept in four groups of 10, 20, 18 and 21 cows respectively on two Swiss farms: two groups were kept as suckler cows and two groups as dairy cows. Each focal cow was separated on two occasions, once for a short (median: 1 day; high oestrus in dairy, late pregnancy or lactation in suckler cows) and once for a longer (median: 2 days; high oestrus in dairy, calving in suckler cows) period. During the 6 h following the re-introduction, agonistic behaviour was recorded. Occurrence of fresh wounds was noted 10 h after re-introduction. As an indicator of physiological stress, faecal samples were collected and concentrations of the cortisol metabolite 11,17-dioxoandrostanes (11,17-DOA) were determined. All data were analysed using generalised linear mixed-effects models.Frequency and duration of agonistic interaction increased with longer separation (p < 0.02) and quickly decreased during the hours following the re-introduction of the focal cow (p < 0.001). The risk of injuries did not significantly change with duration of separation. Separating the cow from her group brought about an increase in concentration of 11,17-DOA (p = 0.012) that decreased over time (p < 0.001). Interestingly, concentrations during the re-introduction phase were lower in comparison with the separation phase (p < 0.001). The concentration of 11,17-DOA was lower during the longer separations (p = 0.018). We did not find any difference of practical importance in how cows reacted to long compared to the short separation related to the different hormonal states of dairy and suckler cows during separation, nor related to the changes in hormonal state within the suckler cows.In conclusion, the duration of a separation of a single Hérens cow from her herd should be minimised so as to reduce negative effects resulting from agonistic interactions.     

Effect of feeding Rumen-protected capsule containing niacin,K2SO4, vitamin C,and gamma-aminobutyric acid on heat stress and performance of dairy cows

This study was conducted to evaluate the effects of supplemental rumen-protected capsule (RPC) on animal performance, serological indicators, and serum heat shock protein 70 (HSP70) of lactating Holstein cows under heat stress (HS). During summer months, 30 healthy multiparous lactating Holstein cows with a parity number of 3.1 ± 0.44, 70 ± 15 d in milk, an average body weight of 622 ± 62 kg, and an average milk yield of 32.28 ± 0.96 kg/d, were used. The cows were randomly allocated to two groups: a control group and an RPC-supplemented group (0.13373 kg K₂SO₄, 0.02488 kg vitamin C, 0.021148 kg niacin, and 0.044784 kg gamma-aminobutyric acid per cow). During the 42-d experiment, ambient air temperature and relative humidity inside and outside the barn were recorded hourly every day for the determination of temperature-humidity index (THI). Milk and blood samples were collected every week, and body weight and body condition scoring were measured on day 0. Based on the THI values, the animals had moderate HS. On day 42, the RPC group had lower HSP70, adrenocorticotropic hormone (P = 0.0001), lactate dehydrogenase (P = 0.0338), and IL-6 (P = 0.0724) levels than the control group, with no significant differences in creatine kinase, glucocorticoid, or IL-2 levels. Milk yield, energy-corrected milk, and dry matter intake were higher in RPC than in the control group (P = 0.0196). There were no significant differences in milk fat or daily protein levels between the two groups; however, daily protein and milk fat levels were higher in the RPC group than in the control group (P = 0.0114 and P = 0.0665, respectively). Somatic cell counts were no different between the two groups. In conclusion, RPC may alleviate HS and improve dairy cow performance.     

Variation in blood leucocytes,somatic cell count,yield and composition of milk of crossbred goats

Ten multiparous crossbred goats, five each of alpine × beetal (AB) and saanen × beetal (SB) were selected from the National Dairy Research Institute goat herd immediately after parturition. These were managed as per the practices followed in the institute’s goatherd. Blood and milk samples were collected at biweekly intervals from day 14 post-kidding for 22 weeks (154 days). Somatic cell count, electrical conductivity, fat, protein and lactose contents of milk were determined using standard methods. In the blood samples total leucocytes and differential leucocytes were also determined. Somatic cell counts were high immediately after parturition on day 14 of lactation and declined gradually with advanced lactation. There were individual variations (P < 0.01) in somatic cell counts between different lactation periods. Somatic cell count of milk was negatively correlated with neutrophils only (P < 0.05) and was neither correlated with milk yield, or with fat, protein, lactose content of milk. Electrical conductivity of milk was low up to four weeks of lactation and thereafter increased as the lactation advanced. Lactose content of milk declined gradually with the advancement of lactation. Fat content of milk was stable up to the eighth week and thereafter increased with advancement of lactation while the protein content of milk did not change significantly during lactation.     

Effect of administration of live Saccharomyces cerevisiae on milk production,milk composition,blood metabolites,and faecal flora in early lactating dairy goats

The effects of live Saccharomyces cerevisiae (CNCM I-1077) supplementation to 72 Saanen dairy goats in early lactation were investigated. Animals were divided into treatment and control groups balanced for parity and milk production in the first 3 weeks of lactation. Treated animals received 0.2 g/day yeast supplement (Levucell SC20) corresponding to 4 × 10⁹ cfu/day S. cerevisiae, beginning week 3 of lactation, and lasting 15 weeks. Dry matter intake (DMI), body condition score (BCS), milk production and composition were recorded to day126 postpartum. Milk samples were analysed weekly for fat, protein, lactose, urea and SCC. Blood samples were analysed monthly for glucose, BHBA, NEFA, GOT and GGT. Intestinal microflora were assessed monthly in faeces, assaying total bacteria, enterobacteria, E. coli, coliform bacteria, clostridia, lactobacilli, molds and yeast. BCS was not affected by the treatment, but treated animals had greater DMI (2.71 kg/day versus 2.35 kg/day, S.E. ±0.12, P < 0.001) and produced more (P < 0.05) milk (2.38 kg/day versus 2.08 kg/day, S.E. ±0.14) of lower fat content (P < 0.05). Plasma metabolites and liver enzymes (GOT, GGT) were similar between groups, although BHBA levels tended to be lower (P = 0.06) in treated animals. Faecal E. coli were reduced (0.72 log₁₀ cfu/g versus 2.39 log₁₀ cfu/g, S.E. ±0.38, P < 0.05) and lactobacilli increased (P < 0.05) by the treatment. Yeast faecal levels were higher (P < 0.001) in treated animals during supplementation. In this study, live yeast supplementation to early lactating dairy goats significantly increased milk production, in relation to increased DMI, without decreasing BCS. Plasma metabolites (glucose, BHBA and NEFA) were consistent with the BCS findings (no differences between groups) and in addition there was a significant reduction of faecal E. coli content together with increase in lactobacilli in the treated animals, suggesting greater stability of the intestinal ecosystem. Results suggest that the inclusion of Saccharomyces cerevisae in the diet of early lactating dairy goats can be recommended under field conditions.     

Genetic and phenotypic parameters for lactation traits in a flock of Saanen goats in Mexico

Heritability, repeatability and genetic and phenotypic correlations of total milk production (TM), cumulated milk production to 120 days (M120) and lactation length (LL), were estimated from the analysis of 1413 records (566 does) obtained from a Saanen goat flock in Querétaro, Mexico, during 1991–1997. Variance components were estimated using a restricted maximum likelihood procedure and applying an animal model. The model included the fixed effects of year–season of kidding, litter size and age of doe, and random effects of animal, permanent environment and residual. For TM, M120 and LL estimates of heritability were 0.22 ± 0.07, 0.12 ± 0.05 and 0.04 ± 0.03, and of repeatability were 0.40, 0.27 and 0.11, respectively. Genetic correlations between TM and M120, TM and LL, and M120 and LL, were 0.98, 0.58 and 0.53, respectively. Phenotypic correlations ranged from 0.30 to 0.83. The correlated selection response for TM from indirect selection on M120 was 71.5% of that expected from direct selection. Efficient selection for TM is possible and M120 could be used as an early indicator of TM, due to the high indirect selection response calculated.     

Identifying activity patterns from activity counters in ETHOSYS® collars on red deer

Identifying activity patterns of animals from activity counts recorded by sensors in the storage-telemetry-system ETHOSYS^® requires to calibrate activity counters to field activities. We continuously observed from dawn to dusk during days 1, 3 and 5 three collared red deer hinds introduced into a 1-ha enclosure for five consecutive days in February (winter), May (spring) and July (summer) 2001. On the basis of concurrently count data collected every 5 min for each hind and each season, we selected the threshold sensor values which best allowed separation of inactive (mainly in the lying position) and active bouts. In winter and spring, the threshold sensor values ranged from 5 to 20 counts per 5 min, which allowed to correctly classified 90.1–98.5% of diurnal sampling intervals. However, higher threshold values (from 55 to 110 counts per 5 min) were found in summer, because foraging and lying periods occur more frequently together within the 5-min interval counts. So, only 76.9–81.4% of sampling intervals were correctly discriminated. To compare the daily activity patterns of hinds in each season, the percentage of time spent active was calculated on a hourly basis. Synchronized periods of activity occur among the three hinds throughout a 24-h period both in winter and summer. However, especially during daytime, the activity patterns of hinds differed significantly in spring. This could affect interpretation of activity patterns of animals from activity counts averaged from several individuals, even if having similar status and environmental conditions or over periods longer than the interval count adopted in the present study.     

Proliferation and apoptosis in subcutaneous adipose tissue of lactating cows with different genetic merit for milk yield

The aim of this study was to investigate the adipocyte size and fate in subcutaneous fat (scAT) of cows diverging for genetic merit at mid lactation stage, when anabolic activity increases and animals are in a state of positive energy balance. Twenty mid lactation cows (180 ± 20 days in milk) grouped according to the Estimated Breeding Values (EBV) for milk yield in plus (EBVp) and minus (EBVm) variants were selected. Average of adipocytes area, proliferation and apoptotic labelling index as well as DLK-1 expression, a marker of pre-adipocytes, were immunohistochemically evaluated in scAT biopsies. In EBVp cows, the BCS was lower (P < 0.01) whereas milk yield, protein, fat yield (P < 0.001) and plasma free fatty acid concentration (P < 0.05) were higher. The scAT of EBVp cows showed a significantly (P < 0.001) higher frequency between 500 and 3000 μm² classes in comparison to EBVm cows, that showed a significantly (P < 0.01) higher apoptotic labeling index. The immunohistochemical reaction showed DLK-1 positivity in scAT of EBVp cows. Taking together, the data indicate a link between milk yield genetic merit of cows, scAT morphology and function, suggesting greater dynamics and metabolic flexibility in EBVp cows.     

Diet and nutrition of range goats on a sarcocaulescent shrubland from Baja California Sur,Mexico

Botanical composition of diets of range goats was studied to determine seasonal preference indices of forage species and nutritional quality of selected diets on a sarcocaulescent shrubland from the Sonoran desert in Baja California Sur, Mexico. Extrusas from five esophageal cannulated adult female goats (40 kg of BW) were collected at the beginning and at the end of each season from April of 2001 to March of 2002. At the end of spring, goats selected higher amounts of browse legumes and cacti species, but during late summer, autumn and winter goats mainly preferred browse non-legumes followed by forb species. Goats selected a constant diet in truly digestible crude protein (annual mean = 11 ± 0.4% DM) and metabolizable energy (2.4 ± 0.1 Mcal kg⁻¹) throughout the year. However, during late spring and early summer, goats selected diets higher in non-structural carbohydrates (NSC), truly IVDOM and truly digestible NSC. Dietary Ca, Mg, K, Mn, Fe were in substantial amounts to meet requirements of a range goat weighing 40.0 kg BW consuming 76.3 g DM kg^0.75 d⁻¹ in all seasons. It is concluded that range goats may require supplementary protein and energy to overcome pregnancy and lactation requirements throughout the year. Copper content appeared marginally deficient almost the entire year and Zn during late summer and autumn.     

Endocrine responses and milk emission characteristics in high yielding Alpine dairy goats under once daily milking management

This study was done to verify if the lack of increase of milk fat content observed in Alpine dairy goats under once daily milking (ODM) compared to twice daily milking (TDM), results from disturbances of animals and/or milk ejection reflex. In this respect, we determined the milk yield and composition in the same 12 multiparous Alpine dairy goats when they were managed first under TDM (period 1: P1) and then under ODM (period 2: P2). Furthermore, oxytocin (OT) and cortisol (CORT) releases and milk emission kinetic of these goats were measured at morning milking 2 and 4 times in P1 and P2, respectively.ODM compared to TDM, caused 18 and 23% reductions, respectively in daily milk yield and milk fat content without milk protein content modification.Although baseline concentration of blood OT was lower under ODM than TDM management (7.0 pg/mL vs 17.8 ± 2.0 pg/mL, respectively), ODM did not modify the total amount of OT released during milking (15,484 pg/mL/32 min vs 18,996 ± 2865.3 pg/mL/32 min, respectively), the peak concentration of OT (57.2 pg/mL vs 73.6 ± 10.5 pg/mL, respectively) or the time to reach it (3.0 min vs 2.0 ± 0.5 min, respectively) by comparison to TDM.ODM compared to TDM, never modified the baseline concentrations of CORT (6.1 ng/mL vs 7.1 ± 1.1 ng/mL, respectively), the total amount of CORT released (11,727 ng/mL/32 min vs 10,073 ± 1522.2 ng/mL/32 min, respectively), the peak concentrations of CORT (16.1 ng/mL vs 15.1 ± 2.1 ng/mL, respectively) and the time to reach it (13.1 min vs 11.0 ± 1.5 min).During ODM, milk flow latency was reduced (−61%) while the mean flow rate was increased (+28%) by comparison to TDM. ODM compared to TDM management, did not modify the maximum flow rate (1.6 L/min vs 1.6 ± 0.2 L/min, respectively) or the time to reach this maximum (103.0 s vs 95.0 ± 10.0 s, respectively). The total milking duration at morning milking was not different (250.0 s vs 221.0 ± 22.0 s, respectively) although the morning milk yield was significantly higher under ODM management (2.63 kg/d vs 1.87 ± 0.1 kg/d, respectively).This results show that milk emission is improved under ODM management in Alpine goats without inhibition or disturbance of neuro-hypophyseal OT release pattern and lack of activation of the hypothalamic–pituitary–adrenal axis and plasma cortisol increase, disproving our initial hypotheses of a disturbance of animals and/or incomplete milk ejection to explain the low fat content of milk under ODM in this breed.     

Effect of in vitro zinc supplementation on HSPs expression and Interleukin 10 production in heat treated peripheral blood mononuclear cells of transition Sahiwal and Karan Fries cows

The changing climatic scenario with apprehended rise in global temperature is likely to affect the livestock adversely vis-à-vis production and reproduction. This has prompted more focus in addressing the unfavorable effects of thermal stress in livestock system. Presuming that the trace element zinc is indispensible for cellular antioxidant system and immune function, the present study was designed to investigate the effect of zinc treatment on heat stress alleviation and immune modulation in peripheral blood mononuclear cells (PBMC) of indigenous and crossbred transition cows. Twelve cows, six each of Sahiwal and Karan Fries (KF) in their second parity with confirmed pregnancy were selected for the experiment. The blood samples were collected at −21, 0 and +21 days in relation to expected date of calving. The experiment was carried out in vitro after isolating PBMC from whole blood. The 48 h cultured PBMC were subjected to assorted levels of exposures viz. 37 °C, 42 °C to impose heat stress and 42 °C+zinc to alleviate heat stress and modulate immunity. The PBMC viability was 86%, 69% and 78%, respectively. The mRNA expression of heat shock proteins (HSP 40, 70 and 90α) and Interleukin-10 (IL-10) production varied between the two breeds vis-à-vis days and levels of exposure. The mRNA expression of HSP40 and HSP70 was significantly (P<0.05) higher in Karan Fries than the Sahiwal cows. Both the breeds showed maximum expression of HSP on the day of parturition, more so in KF than Sahiwal. There was a significant (P<0.05) difference in the HSP mRNA expression at different levels of exposure. Zinc treatment to heat stressed PBMC caused a significant (P<0.05) down regulation of HSP. For immune status, anti-inflammatory cytokine, IL-10 in the culture supernatant was accessed. The IL-10 was significantly (P<0.05) higher in Karan Fries (168.18±14.09 pg/ml) than the Sahiwal cows (147.24±11.82 pg/ml). The IL-10 concentration was highest on the day of calving. Zinc treatment reduced the IL-10 concentration. From the study, it could be concluded that the zinc supplementation in heat stressed PBMC can ameliorate thermal stress and modulate immune response which can act as a model for reducing heat stress during the periparturient period in tropical livestock.     

Increasing the interval between winter outdoor exercise aggravates agonistic interactions in Hérens cows kept in tie-stalls

Cows of the dual-purpose Hérens breed are highly motivated to engage in dominance interactions and thus famous for the cow fights traditionally organised by Swiss breeders. However, this characteristic may result in excessively aggressive behaviour when cows kept in tie-stalls meet during winter outdoor exercise. This can be dangerous for both animals and breeders in terms of likelihood of injury. Regular outdoor exercise is important for the health and social behaviour of cows, and is mandatory in Switzerland. The aim of this study was to find the maximum interval between two exercise days that leads to a minimum of agonistic interactions between the cows.The study was conducted with 51 horned Hérens cows kept on six Swiss working farms. The length of the interval between days with winter outdoor exercise (daily, every third, fourth or fifth day) was experimentally increased on each farm. At the beginning of the experiment, information on social parameters (dominance index and dominance index difference) was collected for each animal and dyad. During the first 40 min of each exercise period (divided into four time-blocks of 10 min each), agonistic and allogrooming behaviour were recorded for each cow. In order to evaluate the risk of injury, all fresh wounds were noted after each exercise period, with three body parts (head, udder, rest of body) being differentiated. All data were analysed using linear mixed-effects models.The frequency of agonistic interactions increased along with the interval between two days of exercise (p < 0.001), and decreased in the course of the exercise on a given day (p < 0.001). The duration of fights increased if the interval between exercise was longer than three days. The frequency of agonistic interactions without body contact increased along with the increasing dominance index of the actor cow (from the omega to the alpha animal, p < 0.001), and, at the same time, the proportion of agonistic interactions with body contact decreased with increasing difference in dominance index between the interacting cows (p < 0.001). The risk of injury to the udder and the body (except for the head) also increased along with an increasing interval between exercise periods (udder: p < 0.001; body: p < 0.001).In conclusion, cows of the Hérens breed show pronounced agonistic behaviour after only a few days of tethering in comparison with cows who have daily winter outdoor exercise. Based on our results, the length of the interval between exercise days should be as short as possible, and in any case not longer than three days.     

Postpartum resumption of ovarian cycling activity in first-calf suckled beef cows exposed to familiar or unfamiliar bulls

The objective of this experiment was to determine if the proportion of first-calf suckled beef cows that resumed ovulatory cycles and the interval to resumption of ovarian cycling activity differ after exposure to either “unfamiliar” bulls or cows on d 35 postpartum, after exposure to either “familiar” bulls or cows for the first 30–32 d after calving. Fifty Angus × Hereford cows were stratified by calving date, calf BW, and calf sex by d 3 postpartum, and assigned to be exposed to familiar epididectomized bulls (BEF; n = 25) or familiar mature ovariectomized (OVX) cows (CEF; n = 25). On d 35 after calving, 12 BEF cows were assigned to be exposed to unfamiliar bulls (BEU); likewise, 12 CEF cows were assigned to be exposed to unfamiliar OVX cows (CEU). Cows were in their treatments for either 95 d (BEF and CEF) or 60 d (BEU and CEU) during the experiment. Blood samples were collected every third d from the beginning to the end of the experiment. A rise in progesterone concentration of >0.5 ng/mL in consecutive samples was used as the criterion for resumption of ovulatory cycles. Exposing cows to bulls on d 5 after calving and then switching a subset of these cows to be exposed to unfamiliar bulls 30–32 d later did not (P > 0.10) alter: (1) the proportion of cows that resumed cycling activity; and (2) postpartum interval to resumption of ovarian cycling activity compared to cows exposed to familiar bulls. However, 32% more (P < 0.05) cows exposed to bulls (BEF and BEU) resumed cycling activity by approximately 14.8 d before cows that were exposed to OVX cows (CEF and CEU). We conclude that the familiarity of first-calf cows to either bulls or ovariectomized cows, did not affect the postpartum occurrence of cycling activity or the interval from calving to resumption of ovulatory cycles. However, bull exposure, whether familiar or unfamiliar, stimulates first-calf cows to resume ovulatory cycles sooner after calving than if they are not exposed to bulls.     

Iodine concentration of milk in a dose–response study with dairy cows and implications for consumer iodine intake

Most feed is poor in iodine and iodine supplementation of cow's diets must guarantee milk iodine concentrations for humans that contribute to prevention of the deficiency and minimize the risk of exceeding an upper limit of iodine intake. Five Holstein cows were fed four iodine doses (via Ca(ΙO₃)₂·6H₂O). In four sequential 14-d periods, doses of 0.2 (basal diet), 1.3, 5.1, and 10.1 mg iodine kg^?1 diet dry matter (DM) were administered. Samples of milk were collected during each period; blood was also sampled from each cow for each iodine dosage. In an 18-d depletion period, a non-supplemented diet was provided. Iodine was determined by inductively coupled plasma-mass spectrometry. The iodine content of milk and serum reflected the iodine dosages in feed significantly. The levels for the four doses tested in milk were 101±32, 343±109, 1215±222, and 2762±852 μg iodine kg^?1. The total amount of iodine in milk per day was 30–40% of ingested supplemental iodine. Omitting additional iodine resulted in a short-term reduction of serum and milk iodine following an exponential decay function. The iodine supplementation of 0.5–1.5 mg kg^?1 diet DM represents the requirement of the cow, resulting in 100–300 μg iodine L^?1 milk, which optimally contributes to human supply. The maximum dietary levels of former and present EU legislations (10 and 5 mg iodine kg^?1 cow feed) increase the risk of iodine excess in humans.