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For the past 2 decades, the Spooner Agriculture Research Station (ARS) of the University of Wisconsin-Madison operated the only dairy sheep research flock in North America. The objectives of the present study were to 1) obtain estimates of genetic parameters for lactation and reproductive traits in dairy ewes, 2) estimate the amount of genetic change in these traits over time, and 3) quantify the level of inbreeding in this flock over the last 20 yr. Multiple-trait repeatability models (MTRM) were used to analyze ewe traits through their first 6 parities. The first MTRM jointly analyzed milk (180-d-adjusted milk yield [180d MY]), fat (180-d-adjusted fat yield [180d FY]), and protein (180-d-adjusted protein yield [180d PY]) yields adjusted to 180 d of lactation; number of lambs born per ewe lambing (NLB); and lactation average test-day somatic cell score (LSCS). A second MTRM analyzed 180d MY, NLB, LSCS, and percentage milk fat (%F) and percentage milk protein (%P). The 3 yield traits were moderately heritable (0.26 to 0.32) and strongly genetically correlated (0.91 to 0.96). Percentage milk fat and %P were highly heritable (0.53 and 0.61, respectively) and moderately genetically correlated (0.61). Milk yield adjusted to 180 d was negatively genetically correlated with %F and %P (-0.31 and -0.34, respectively). Ewe prolificacy was not significantly (P > 0.67) genetically correlated with yield traits, %P, or LSCS but lowly negatively correlated with %F (-0.26). Lactation somatic cell score was unfavorably genetically correlated with yield traits (0.28 to 0.39) but not significantly (P > 0.09) correlated with %F, %P, and NLB. Withintrait multiple-trait models through the first 4 parities revealed that 180d MY, 180d FY, 180d PY, %F, and %P were strongly genetically correlated across parity (0.67 to 1.00). However, the genetic correlations across parity for NLB and LSCS were somewhat lower (0.51 to 0.96). Regressing predicted breeding values for 180d MY, without and with the addition of breed effects, on ewe year of birth revealed a positive genetic gain of 2.30 and 6.24 kg/yr, respectively, over the past 20 yr in this flock. Inbreeding coefficients of ewes with an extended pedigree ranged from 0.0 to 0.29, with an average of 0.07. To optimize genetic gains and avoid excessive inbreeding, the development of a national genetic improvement program should be a top priority for the growing dairy sheep industry. [ABSTRACT FROM AUTHOR]

The Spooner Agricultural Research Station operated the only dairy sheep research flock in North America through 2016. The original nondairy ewe flock was "bred up" to a crossbred dairy flock through the use of rams and semen of the East Friesian (EF) and Lacaune (LA) dairy breeds. The objective of this study was to determine the environmental and nonadditive genetic effects that influence performance of dairy ewes. The traits analyzed were 180 d adjusted milk (180d MY), fat (180d FY), and protein (180d PY) yields, percentage fat (%F) and protein (%P) in milk, lactation average somatic cell score (LSCS), and number of lambs born per ewe lambing (NLB). The univariate repeatability models included the fixed effects of year of lambing, age, weaning system (except for the trait of NLB), individual breed composition, and individual retained heterosis along with the random additive genetic, permanent environmental, and residual effects. Estimates of heritability were moderate for 180d MY (0.32 ± 0.04), 180d FY (0.26 ± 0.04), and 180d PY (0.29 ± 0.04), high for %F (0.54 ± 0.04) and %P (0.61 ± 0.04), and low for LSCS (0.12 ± 0.03) and NLB (0.08 ± 0.02). Ewes that reared their lambs had lower (P < 0.01) 180d MY, 180d FY, 180d PY, %F, and %P and higher (P < 0.001) LSCS than ewes that had their lambs removed shortly after parturition. Relative to nondairy breeding, EF and LA breeding had positive (P < 0.001) effects on 180d MY, 180d FY, and 180d PY, but a negative (P < 0.03) effect on %P. Purebred EF ewes were predicted to have lower (P < 0.001) %F than purebred LA or nondairy ewes. Purebred LA ewes were predicted to have a higher (P < 0.001) LSCS than purebred EF or nondairy ewes. Purebred EF ewes were expected to be more (P < 0.001) prolific than purebred LA or nondairy ewes. Individual retained heterosis had a favorable (P < 0.01) effect on 180d MY, 180d FY, 180d PY, and NLB. Knowledge of the factors affecting dairy ewe performance are important for dairy sheep producers to make more informed husbandry and breeding decisions. [ABSTRACT FROM AUTHOR]

A satisfactory intake of novel low-quality forages by ruminants may require previous experience with this feed. Therefore, this study test-ed in sheep whether experience with forages from woody plants had an influence on feed intake, feeding behavior, and nutrient supply when offered in a multi-ple-choice arrangement. Two sheep experiments were conducted, 1 in Syria (Mediterranean region; Exp. 1) and the other in Switzerland (Central Europe; Exp. 2), that investigated 5 and 6 woody test plants, respective-ly. In Exp. 1, the test plants were Artemisia herba-alba, Atriplex leucoclada, Haloxylon articulatum, Noaea mucronata, and Salsola vermiculata. In Exp. 2, Betula pendula, Castanea sativa, and Juglans regia were used in addition to A. leucoclada, H. articulatum, and S. ver-miculata (the plants most consumed in Exp. 1). In each experiment, 12 lactating sheep (Awassi sheep in Exp. 1 and East Friesian Milk sheep in Exp. 2) were allocated to 2 groups ("experienced" and "naïve"). Experienced sheep subsequently were familiarized with each test plant during a learning period of binary choices (1 test plant vs. barley straw) for 4 h in the morning for 7 d each. The naïve group received only straw. During the rest of the day, a basal diet composed of barley straw (ad libitum) and concentrate was offered to both groups. For the 2 wk following the learning period, the sheep were subjected to feeding of the basal diet to avoid carryover effects of the last offered test plant. In the following multiple-choice period, both groups were allowed to select from all test plants during 4 h in the morning for 14 d. Forage intake after 4 and 24 h and feeding behavior during the first 30 min of the test feeding were assessed. Milk yield and composition were measured at the end of the multiple-choice period. Nutrient intake was calculated using feed intake mea-surements and compositional analyses. Only in Exp. 2, group differences (P < 0.05) were found on d 1 of the multiple-choice period. The experienced sheep con-sumed more total forage, straw, OM, NDF, ADF, and ADL (nutrients without concentrate). However, across the entire multiple-choice period, there were no differ-ences (P ≥ 0.05) in forage and nutrient intake, feeding behavior, and milk yield and composition between the groups in both experiments. This suggests that sheep can quickly adapt to previously unknown woody feeds of varying origin and quality offered as dried supplements. [ABSTRACT FROM AUTHOR]

Short-scrotum (induced cryptorchid) rams can retain growth and performance characteristics of intact-rams while making them sterile and facilitating co-grazing with ewe-lambs. East Friesian x Lacaune male lambs left intact (n = 19; IN), rendered short-scrotum (n = 17; SS) or neutered (n = 25; WE) by 10 d of age, were used to evaluate libido and semen quality at 7-mo old. Lambs were managed as one group on a forage-based diet supplemented with a grain mixture (barley and soybean meal at 0.7 kg/d). Four CIDR-treated estrus-induced ewes were placed two/pen in adjacent 2.5x2.5 m pens for libido testing. Males were introduced individually to ewe pens for 5 min and reproductive behaviors recorded (anogenital sniffs, foreleg kicks, flehmen, false mounts, and service). Semen was collected from 6 random IN and SS lambs via artificial vaginas using estrus-induced ewes as teasers. Volume was recorded, and ejaculate extended in milk/egg yolk, packaged into straws, and stored at 5°C for analysis with a CASA system the following day. Behavior measurements were compared between types using PROC GLM. Ejaculate characteristics are presented as mean±SD due to insufficient sperm concentrations of SS ejaculates. Anogential sniffs, foreleg kicks, and mounts were similar in IN and SS, and higher (P < 0.05) than in WE (7.44 and 6.34 vs. 4.76; 1.72 and 1.60 vs. 0.17; 1.78 and 2.05 vs. 0.22; respectively). Number of services were higher (P < 0.001) in IN than SS (1.11 vs. 0.53), but time to service (112 sec) was not different. Ejaculate volume was similar in IN and SS (0.51 mL), but SS ejaculates were essentially devoid of sperm. Ejaculates from IN lambs had 0.69x109±0.48 x109 sperm, with 68.9±12.5% progressive motility, 81.8±6.1% viability and 87.1±6.1% morphologic normality. Ram lambs rendered short-scrotum by 10 d of age had reproductive behavior similar to intact post-pubertal rams, but ejaculate characteristics showed them to be sterile [ABSTRACT FROM AUTHOR]

This study evaluated the effects of stage of lactation and supplementation on lactation performance of 95 dairy ewes grazing kura cloverorchardgrass pastures. Ewes lambed in January or April and consumed 0 or 0.82 kg/d of supplement (16% CP mixture of corn and high protein pellet) in a 2 x 2 factorial arrangement of treatments. The trial began when ewes went to pasture on May 25 and continued for 82 days. Unsupplemented ewes in both lambing groups showed a greater range in their daily milk yields than supplemented ewes throughout the trial, probably in direct response to variations in pasture quality during the grazing season. The January lambing ewes compared to the April lambing ewes produced less (P < .001) milk (91.1 vs. 136.8 kg, respectively), milk fat (5.6 vs. 7.8 kg, respectively), and milk protein (4.7 vs. 6.3 kg, respectively) during the trial. The supplemented ewes compared to the unsupplemented ewes produced more (P < .01) milk (123.2 vs. 104.2 kg, respectively), milk fat (7.2 vs. 6.2 kg, respectively), and milk protein (5.9 vs. 5.0 kg, respectively). Supplementation had a similar positive effect on milk, milk fat, and milk protein yield in both lambing groups. Milk urea nitrogen (MUN) can be used as an indicator of the efficiency of protein utilization in sheep. Trial MUN levels across treatments tended to be higher (18 to 34 mg/dL) than recommended levels for sheep (14 to 22 mg/dL), indicating an excess of protein intake. This can be explained by the high quality pastures, which ranged in crude protein from 16 to 30%. Across all treatments, the correlation between pasture crude protein and MUN was .65. Within the supplementation treatment, the correlation was numerically higher but not significantly different than the correlation within the unsupplemented treatment (r = .78 and .52, respectively). [ABSTRACT FROM AUTHOR]

During feed restriction, changes in metabolism occur and often result in the mobilization of energy from the adipose tissue. The objective of this work was to evaluate changes in the fatty acid (FA) profile of milk fat during short-term feed restriction in dairy ewes. Six ewes (3 at low-body condition score and 3 at high-BCS) were fed a complete pelleted diet (CPD) ad libitum (average intake of 2.5 kg/head per d) for 7 days, followed by 3 days of feed restriction of 50% of their previous intake (feed restriction group, FRG). Other 6 ewes (control, C group), divided into 3 low-BCS and 3 high-BCS sheep, were always fed CPD ad libitum (average intake of 2.5 kg/head per d). The CPD composition was (on a DM basis) 38.3% NDF, 16.0% CP and 4.5% EE (of which 2% of palm oil). The data of the 3-d treatment were analysed by a mixed model using BCS, group and their interaction as fixed factors and ewe as random factor. Milk fat content was higher in the FRG than in the C group (5.92 vs 4.67%), whereas fat yield was similar between groups. No effects of short-term feed restriction on C4-C14 fatty acids were observed. The FRG showed a lower content of C16:0 (26.46 vs 29.59%; P≤0.05) and cis9,cis12 C18:2 (4.42 vs 5.38%; P≤0.10) and a higher content of cis9 C18:1 (20.81 vs 17.56%; P≤0.05) than the C group. The content of total CLA (1.47 and 1.27 in the FRG and C group, respectively) was not influenced by the feed restriction treatment. The extent of variation in milk fatty acid profile in FRG group (expressed as percentage respect to C group) was influenced by BCS of ewes. The results suggest that feed restriction for a 3-d period is enough to cause changes in the FA profile of milk fat. The different responses observed in animals with high and low BCS was probably due to a different extent of body store mobilization when feed restriction occurred. [ABSTRACT FROM AUTHOR]

Several factors that contribute to variation in production and quality of ewe milk have been described, such as environment, breed, age of ewe, lactation stage, number of lambs or milking techniques, sanitary condition and udder infections, herd management and nutritional level during gestation and lactation. The objective of this project was to evaluate two milk production systems and their effect on milk chemical composition using 87 Bergamasca ewes. Ewes in one group were separated from their lambs 48 h after birth, while ewes in the second group were kept with their lambs until the lambs were weaned at 60 days of age. All ewes were machine-milked for a period of 90 days. Milk samples were collected once a week for analyses of lactose, protein, fat and total solids using infrared. The analyses were carried out at the Milk Cattle Breeding Management Technology Center, ESALQ/USP, Piracicaba, São Paulo. The data were statistically analyzed using the GLM procedure of SAS. Differences in production of fat, protein, lactose and total solids contents during the whole lactation were observed between the two systems (P<.05). Fat content of the milk from the ewe group without lambs was higher (5.51%) than the ewe group with lambs (3.74%). Differences in protein content of the milk were also found; however, average protein values were within levels reported in previous studies. [ABSTRACT FROM AUTHOR]

In Sardinian dairy flocks, machine milking starts at about 30 days post-partum, after lamb weaning. This is a stress factor, especially in primiparous ewes that are exposed to this practice for the first time. The objective of the trial was to evaluate the effect of milking parlour training before weaning on milk production traits. One week before weaning, six ewes (group A) and their lambs were introduced into the milking parlour and hand-milked once a day, to adapt them to the new environment and noise of the milking machine. Seven ewes (group B) were hand-milked once a day outside the milking parlour until weaning. Milk yield was recorded and milk samples were collected at each milking for the first 10 days of machine milking for fat, protein and somatic cells count (SCC) analysis. Blood samples were collected every day soon afterwards the morning machine milking and analyzed for cortisol levels. Data were analyzed using group and sampling as fixed factors and ewes within group as random factor. No differences between groups were observed in all evaluated parameters. Nevertheless, milk yield, milk fat content and yield, and SCC tended to be lower in group A than in group B. Significant interactions between group and sampling date were observed for all milk traits. Blood cortisol levels were not affected by the treatments during the first 10 DIM. The results suggest that a week of training in the machine parlour did not allow to reduce the stress caused by machine milking and weaning in primiparous ewes. Funded by the BenOLat (MiPAF) project. [ABSTRACT FROM AUTHOR]

Little is known in Brazil about milk production of ewes. As wool and meat production have become important activities in the country, an increasing interest in milk production is observed. Thus, the objective of the present work is to evaluate the effect of the use of bypass fat in the diet of Bergamasca dairy ewes on milk production. Eighty ewes were divided into 2 blocks according to parturition and age. Within each block, half of the animals received either one of two treatments: A - balanced diet (concentrate + corn silage) without bypass fat; and B - same diet as in A with added bypass fat (35g/ewe/day). In both blocks, the lambs were kept with their mothers in pasture during daytime and were separated at night. The lambs were returned to their mothers after the morning milking and were weaned at 45 days of age. The ewes were machine-milked starting 48 hours after parturition, once a day, at 7h A.M., for 60 days. Diets were isoenergetic and isonitrogenous, containing 22% CP and 66% TDN on a dry-matter basis. The statistical analysis was performed by means of SAEG 9.0 (System for Statistical and Genetic Analyses). Statistical differences were not observed (P>.05) between treatments for average daily milk production until 45 days; however, after 45 days, treatment B showed a higher (P<.05) milk yield in comparison to A (540 vs 502 g/ewe/day). This result may be attributed to the use of diet with bypass fat, which supposedly provided better absorption of unsaturated fatty acids in the small intestine. [ABSTRACT FROM AUTHOR]

The objective of this work was to investigate the effect of dietary bypass fat on milk composition of Bergamasca dairy ewes. The experiment was carried out at the Ewe Milk Production Research Unit of the College of Veterinary Medicine and Animal Science of São Paulo State University. Eighty Bergamasca ewes were divided into two groups and fed one of two diets: A - balanced diet (concentrate + corn silage); or B - same diet as A, with bypass fat (35 g/ewe/day) added to the concentrate. Lambs were kept with their mothers on pasture during daytime and were separated at night. After the morning milking, the lambs were returned to their mothers and weaned at 45 days of age. The ewes were machine-milked for 60 days. Milk samples were collected once weekly for analysis of lactose, protein, fat and total solids. The data were analyzed by one-way analysis of variance. For the first 45 days of lactation, significant differences (P<.05) were observed for protein and lactose, with ewes fed diet B having higher means, whereas differences were not observed (P>.05) for fat and total solids. After 45 days of lactation, significant differences (P<.05) were found only for fat and lactose, which may be explained by the higher milk production of ewes fed diet B because some researchers have reported a negative correlation between production and concentration of milk constituents. [ABSTRACT FROM AUTHOR]

Several studies have reported higher milk yields in dairy and nondairy sheep with multiple births. The aim of this experiment was to investigate the influence of twin rate on milk yield in Sarda dairy sheep in both organic (O) and conventional (C) farms. Data derived from the PERSEO-ARA database and consisted of 235 farms (54 O and 181 C); 64,908 ewes (24.7 % in O); 7 years (1996-2002), and the 4 provinces of Sardinia (Italy), i.e. Sassari (SS), Nuoro (NU), Oristano (OR), and Cagliari (CA). Twin rate (expressed as the percentage of lambed ewes which had multiple births) was classified into four classes: low (L ≤ 14%); medium-low (14% ≤ML ≤24%), medium-high (24% ≤MH ≤ 29%), and high (H ≥29%). Mixed procedure of SAS was used to analyse the following model: Yijklmn=μ +Tci+Fj(Tci)+Tk + Cl +Pm+T*Tc+Tc*C+In+ε, where Y=total milk yield (in kg/ewe per year), μ=overall last square mean, Tci=twin-rate class, Fj(Tci)=farm j on twinrate class i (random effect), Tk =year, Cl =farm type, Pm=province, and In=abortion incidence (covariate). Twin rate (μ±se = 23.74%±0.54% ) influenced total milk production (μ±se = 143.33±1.33 kg/ewe per year) in farms belonging to the MH or H classes only, especially in the H class of O farms (149.0 and 164.8 kg/ewe per year in the H class of C and O farms, respectively), with a different trend among the years (interaction P=0.0127). Year and province contributed significantly to explain a relevant part of the variance, similarly to the covariate abortion incidence (P=0.0073; μ±se = 2.31%±0.15%). There were no differences in milk yield between O and C farms, even if the interaction between farm type and twin-rate class was highly significant (P=0.002). [ABSTRACT FROM AUTHOR]

Most of Brazilian breeds present capability for meat or wool production, but it is possible to find animals with dairy properties. Bergamasca ewes, for example, introduced in Brazil in 1940, are raised in the Northeast for meat production. Considering their Italian origin, they could be used for milk production; however, the amount of milk produced by lactation and its characteristics are not well known. In view of this, the objective of the present work, carried out at the Ewe Milk Production Research Unit of the College of Veterinary Medicine and Animal Science of the São Paulo State University (UNESP), is to evaluate the effect of the different management systems on milk production of Bergamasca ewes. Eighty seven ewes were used and submitted to two milk production systems. In the group without lambs, these were separated from their mothers 48h after birth, while, in the mixed group, lambs were kept with their mothers until to 60 days of age, when they were weaned. Both ewes from the group without lambs and from the mixed group were machine-milked for a period of 90 days and milk production was daily measured during the whole experimental period. The statistical analysis was performed by means of the GLM procedure of the Statistical Analysis System (SAS, 1985). Ewes managed in the group without lamb presented higher (P<.05) daily average milk production in comparison to the mixed group. This difference may be explained, in part, by milk injection inhibition during machine-milking. In the beginning of lactation, the absence of a proper sign during machine-milking, which is usually present when females are nursing their lambs, inhibits the release of ocytocin and milk ejection reflex. [ABSTRACT FROM AUTHOR]