Ewe Flock Research Articles

Histopathological and Serological Analysis of Aborted Ewes and Neonatal Death with Toxoplasma gondii in Duhok City, Kurdistan-Iraq.

This study was carried out on seven flocks of ewes suffered from late abortion and neonatal mortality with the prevalence rate of infection reported as 13.95%. The blood and tissue samples were collected from the aborted ewes in several flocks of Duhok province, Kurdistan Region, Iraq. Serological analysis indicated that all the aborted ewes were confirmed positive for agglutination to Toxoplasma gondii (T. gondii)antibody. The investigation of the aborted fetuses showed the blood-stained fluid in the thoracic and abdominal cavity. Most of the aborted fetuses had also enlarged, congested, and friable livers and lungs. The placenta was swollen, reddish, and friable, and its cotyledons also spotted with whitish foci. T. gondii tachyzoites were also demonstrated in the placental sections of some aborted ewes. Severe congestion, necrosis, and infiltration of multinucleated cells were the most predominant histopathological changes of the aborted fetuses, as well as presented tissue cysts, tachyzoites, and bradyzoites in the liver, brain, heart, and lung. There were also several clusters of dark purple banana-shaped T. gondii tachyzoites within the brain and heart tissues in most of the examined aborted fetuses in different flocks. T. gondii tachyzoites were also detected from the peritoneal ascites of mice inoculated experimentally 12 days following the infection. Moreover, T. gondii tissue cysts were detected from the impression smears of the mice brains 32 days after the infection. Accordingly, the demonstration of T. gondii in Giemsa-stained impression smears associated with characteristic histopathological changes of different organs is a great fundamental method for the diagnosis of T. gondii in aborted cases.

Economic assessment of potential efficiency gains in typical lamb production systems in the alpine region by using local resources

Abstract The alpine region is very suitable for sheep farming, which keeps the landscape open and produces meat by using local resources. However, the market has more potential than currently realised, but the profitability of lamb production needs to be improved. Management changes would allow efficiency gains and could be implemented on farms in the short or medium term. Thus, based on traditional high-quality forage management in the Swiss alpine region, we analysed the profitability of lamb production systems by full-cost accounting and by examining the economic impact of variables such as productivity, live weight and fattening management for two typical (standardised) farms: 1) farm with 200 sheep (Hill-200) in a hilly area with accelerated lambing and 2) farm with 140 sheep (Mount-140) in a mountainous area with seasonal lambing once per year. In both farm types, conventional breed types resulting from displacement crossing were kept on a constant forage area. The analyses were based on accountancy data and face-to-face interviews with farmers on 15 single farms in different regions. For Hill-200, next to other simulated management interventions the most promising was shortening the lambing interval to 240 days (3 lambings in 2 years), resulting in a substantial increase in gross margin (+44 %), return on labour (+27 %) and income per hectare (+57 %) compared with the baseline scenario. The carcass weight per hectare increased from 202 to 265 kg. A lambing interval of 240 days compared with seasonal lambing (365 days) increased the income per hectare by 82 %. For Mount-140, the most promising simulated management interventions were increasing the litter size, reducing concentrate input and extending the fattening period. When combined, these interventions resulted in a substantial increase in gross margin (+58 %), return on labour (+38) and income per hectare (+63 %) compared with the baseline scenario. The carcass weight per hectare increased from 153 to 194 kg. The improvements based on our model calculations are practicable by changing the ewe flock to original genetics characterised by higher prolificacy, less weight and greater hardiness. When crossed with rams of meaty breeds, these ewes can be expected to produce vigorous hybrid lambs with a similar growth rate and carcass quality compared with lambs of ewes in the current (baseline) systems.

Reducing the level of nutrition of twin-bearing ewes during mid to late pregnancy produces leaner prime lambs at slaughter

The Australian prime lamb industry is seeking to improve lean meat yield (LMY) as a means to increasing efficiency and profitability across the whole value chain. The LMY of prime lambs is affected by genetics and on-farm nutrition from birth to slaughter and is the total muscle weight relative to the total carcass weight. Under the production conditions of south eastern Australia, many ewe flocks experience a moderate reduction in nutrition in mid to late pregnancy due to a decrease in pasture availability and quality. Correcting nutritional deficits throughout gestation requires the feeding of supplements. This enables the pregnant ewe to meet condition score (CS) targets at lambing. However, limited resources on farm often mean it is difficult to effectively manage nutritional supplementation of the pregnant ewe flock. The impact of reduced ewe nutrition in mid to late pregnancy on the body composition of finishing lambs and subsequent carcass composition remains unknown. This study investigated the effect of moderately reducing ewe nutrition in mid to late gestation on the body composition of finishing lambs and carcass composition at slaughter on a commercial scale. Multiple born lambs to CS2.5 target ewes were lighter at birth and weaning, had lower feedlot entry and exit weights with lower pre-slaughter and carcass weights compared with CS3.0 and CS3.5 target ewes. These lambs also had significantly lower eye muscle and fat depth when measured by ultrasound prior to slaughter and carcass subcutaneous fat depth measured 110 mm from the spine along the 12th rib (GR 12th) and at the C-site (C-fat). Although carcasses were ~5% lighter, results showed that male progeny born to ewes with reduced nutrition from day 50 gestation to a target CS2.5 at lambing had a higher percentage of lean tissue mass as measured by dual energy X-ray absorptiometry and a lower percentage of fat during finishing and at slaughter, with the multiple born progeny from CS3.0 and CS3.5 target ewes being similar. These data suggest lambs produced from multiple bearing ewes that have had a moderate reduction in nutrition during pregnancy are less mature. This effect was also independent of lamb finishing system. The 5% reduction in carcass weight observed in this study would have commercially relevant consequences for prime lamb producers, despite a small gain in LMY.

Study on Sero-Prevalence of Small Ruminant and Human Brucellosis in Yabello and Dire Districts of Borena Zone Oromia Regional State, Ethiopia

Cross-sectional study was conducted in Yabello and Dire districts of Borena zone Oromia regional state, Ethiopia to estimate sero-prevalence of small ruminant and human Brucellosis. Sero-survey was applied to the target population of 228 small ruminants and 86 humans. The sera samples were collected from small ruminants (sheep and goats) and humans for serological analysis of brucellosis. Samples were serially tested by RBPT and positive samples were finally confirmed by c-ELISA. The overall sero-prevalence of brucellosis were 8.8% (95% CI: 5.4-13.2) and 25.6% (95% CI: 16.8-36.1) in small ruminants and humans respectively. There was a statistically significant variation in Brucella infection (p<0.05) in humans. The higher prevalence recorded in elders. The highest recorded in small ruminant sampled from large flock size and ewes with a retained fetal membrane. These results provide evidence of the importance of brucellosis in humans and small ruminants in the study area. Overall, the existence of brucellosis, community daily practice and uncontrolled movement of animals and livelihood nature of pastoralists suggest the need for farther investigation of brucellosis in humans and animals. Furthermore, awareness creation or public health education on zoonotic importance of brucellosis and prevention techniques should be imparted continuously in pastoral communities.

Repeatabilities, heritabilities and correlations of methane and feed intake of sheep in respiration and portable chambers

Context Knowledge of genetic and phenotypic variation and the accuracy of different measurement techniques is needed to successfully reduce livestock methane (CH4) emissions. Aims To estimate repeatabilities, heritabilities and genetic correlations of respiration-chamber (RC) and portable accumulation-chamber (PAC) measurements using two different protocols but the same management and feeding conditions. Methods Australian Information Nucleus Flock ewes were measured in seven test-batches. The 510 ewes were removed from pasture and habituated to chaffed alfalfa and cereal hay at 1.5–1.6 times maintenance. Methane was measured in RC for two 22-h periods approximately 14 days apart, and 40 min in PAC, either immediately after removal from individual pens (with feed as described above, PAC0), or 1-h after withdrawing feed (PAC1). There were up to 48 PAC0 tests per day (at 0930 hours, 1100 hours, 1230 hours, 1400 hours in 12 PAC) and 24 PAC1 tests per day (at 1100 hours and 1300 hours). Test methods (RC, PAC0, PAC1) were analysed as different traits in a multi-trait repeated-measures model. Key results Before adjustment for liveweight (Lwt) or feed intake (FI), CH4 was highly repeatable (RC 78%, PAC0 83%, PAC1 82%), with heritabilities of 39–55%, permanent environmental (PE) animal variances 23–43% of phenotypic variances (Vp), high genetic correlations between methods (98–100%), and lower PE correlations (44–58%). A second PAC test on the same day decreased CH4 by 8–12% compared with the ewe’s first test that day. Heritabilities of FI from 0800 hours until the test was complete (FIOD) were 16–17% (PAC) and 25% (RC) before adjusting for Lwt, with high PE variances (PAC 67–73%, RC 41% of Vp). FI in the previous 24 h was highly heritable and much less variable than was FIOD in the RC, suggesting that testing introduced additional variation by disrupting feeding patterns. After adjusting CH4 for Lwt, FIOD and FI in the previous 24 h and Lwt, some additive genetic variation remained, averaging 17% of Vp. Multivariate models of CH4 and FI, fitting a single animal term (representing genetic+PE variation) showed high animal correlations between FI and CH4, namely, 90–95% before, and 86–95% after adjusting for Lwt. Conclusions PAC measurements are heritable and highly correlated with RC measurements under similar management conditions. The high genetic and animal correlations of PAC CH4 and FI imply that CH4 is a useful proxy for FI of grazing animals.

Medieval Dairying: A Ewe Flock in Fourteenth-Century Malham

A sixteenth-century manuscript in the Lancashire Archives casts light both on fourteenth-century dairying practices and a post-Dissolution property dispute in Malham, Craven, North Yorkshire.

The effect of ewe wastage in New Zealand sheep and beef farms on flock productivity and farm profitability

Changes in the relative value of meat and coarse wool have led to the majority of income for New Zealand sheep farms now coming from the sale of animals for slaughter rather than wool, shifting the production focus for many farmers. Ewe wastage, on-farm mortality and premature culling before the potential end of the ewe's productive life, is a limiting factor for sheep meat production. Current estimates of wastage rates in New Zealand commercial ewe flocks range from approximately 3 to 20%. A bio-economic model of a representative New Zealand North Island Hill Country sheep farm was constructed to investigate the effects of wastage rates on farm profitability. The model used system dynamics with annual time steps over 30 years. The proportion of ewes that were culled up to 6 years of age and all mature ewe deaths combined were considered as wastage in this study. Modelled scenarios covered ewe wastage rates ranging from 5 to 21% for a self-replacing flock of 1879 ewes producing coarse wool and lambs for sale on 423 ha where 63% of total feed was consumed by sheep. Greater wastage of ewes resulted in higher numbers of young, less productive replacement ewes in the flock, lowering average flock age from 4.18 years to 3.54 years over the wastage rate range tested. The reproductive performance of the flock decreased with flock age from 1.33 lambs weaned per ewe presented for breeding to 1.22 lambs weaned per ewe presented for breeding with wastage rates of 5% and 21%, respectively. The lower numbers of lambs weaned and lower proportion available for sale reduced income from lamb sales. Subsequently, total cash operating surplus for the sheep enterprise of the representative farm was reduced by NZ$ 1069 per year per 1% increase in ewe wastage. For a New Zealand North Island Hill Country sheep farm with 15% of the flock lost due to wastage, a 10% reduction in wastage could increase cash profit by 17%. Sheep energy requirements were reduced across the production year with greater ewe wastage leading to a greater positive end of year cumulative feed surplus.

Production responses and cost-benefit of long-acting pre-lambing anthelmintic treatment of yearling ewes in two commercial flocks in New Zealand

AIMS: To investigate the production responses and cost-benefit of administering a controlled-release anthelmintic capsule (CRC) to pregnant yearling ewes prior to lambing.METHODS: Yearling ewes from two commercial sheep flocks (A, n=489; B, n=248) in the North Island of New Zealand were enrolled in the study. Prior to lambing, CRC containing albendazole and abamectin were administered to half the ewes while the other half remained untreated. Ewe liveweights and body condition scores were measured prior to lambing, at weaning and, for Flock B, prior to subsequent mating. Lambs were matched to dams shortly after birth and the weight and number of lamb weaned per ewe were determined. A cost-benefit analysis was undertaken for Flock B considering the increased weight of lamb weaned per ewe, and the weight of ewes at the next mating and the benefit in terms of lambs born.RESULTS: The mean weight at weaning of treated ewes was greater for treated than untreated ewes by 2.76 (95% CI 0.64–4.88) kg in Flock A (p<0.001) and 2.35 (95% CI −0.41–5.12) kg in Flock B (p=0.003); the weight of lamb weaned per ewe was greater for treated than untreated ewes by 1.43 (95% CI −0.71 to –3.49) kg in Flock A (p=0.041) and 3.97 (95% CI 1.59–6.37) kg in Flock B (p<0.001), and ewe liveweight prior to subsequent mating was greater for treated than untreated ewes in Flock B by 4.60 (95% CI 3.6–5.6) kg (p<0.001). There was no difference in the percentage of lambs reared to weaning between treated and untreated ewes in either flock (p>0.8). The overall cost-benefit of treatment for Flock B was NZ$9.44 per treated ewe.CONCLUSIONS AND CLINICAL RELEVANCE: Pre-lambing CRC administration to yearling ewes resulted in increased ewe weaning weights and weight of lamb weaned in both the flocks studied. There was an economic benefit in the one flock where this was assessed.

Rambouillet and Romanov reciprocal breed effects on survival and growth traits of F1 lambs and on reproductive traits of F1 ewes.

Objectives were to estimate reciprocal effects of Romanov and Rambouillet breeds on survival, growth, and reproductive traits of F1 progeny and direct breed effects (Suffolk and Composite - ½ Columbia, ¼ Hampshire, and ¼ Suffolk) on survival and growth traits of the subsequent terminally sired lambs. Mature Rambouillet ewes (n = 243) were exposed to 20 Romanov rams over two seasons producing 621 lambs for evaluation of growth and survival traits with 274 F1 ewes being evaluated for reproduction traits through 4 yr of age. Similarly, mature Romanov ewes (n = 116) were exposed to 20 Rambouillet rams producing 601 lambs for evaluation of growth and survival traits with 176 F1 ewes being evaluated for reproduction traits through 4 yr of age. A total of 433 of those F1 ewes produced 3,431 lambs (1,552 litters) from 1,634 exposures to terminal sires over 4 yr. Terminal sires consisted of 38 Suffolk and 44 Composite rams. Reciprocal crossbred ewe lambs were produced from dramatically different uterine and neonatal environments, with litter size at birth from Romanov dams exceeding those from Rambouillet dams by 1.52 lambs (P < 0.001) and birth weight of lambs from Romanov dams averaged 3.41 kg compared with 4.26 kg from Rambouillet dams. Differences in BW were still evident at 140 d (P < 0.001) for dam-reared lambs. However, reciprocal ewe first breeding BW of both types were similar (P = 0.38). Minimal differences were observed in performance of reciprocal cross ewes through 4 yr for productivity, longevity, or progeny growth and survival. One exception was BW at 140 d where an interaction of dam breed with terminal sire breed reached significance for both dam-reared (P = 0.05) and nursery-reared (P = 0.02) lambs. This interaction was due to the lower weight of Composite-sired lambs out of reciprocal cross ewes born from Rambouillet dams. Composite rams increased number born (P < 0.01) and number weaned (P < 0.05) of the reciprocal cross ewes. Suffolk rams increased (P < 0.001) BW and growth rates from birth to 140 d of terminal progeny. Thus, there were little cumulative differences accrued over the 4 yr and no differences were detected for cumulative kilogram of lamb generated at 140 d per ewe exposed. The practical outcome of this evaluation was that performance levels of both types of Romanov crossbred ewes was similar allowing the industry to produce the desired crossbred ewes without needing large purebred ewe flocks of the less numerous Romanov breed.

Carbon and blue water footprints of California sheep production.

While the environmental impacts of livestock production, such as greenhouse gas emissions and water usage, have been studied for a variety of US livestock production systems, the environmental impact of US sheep production is still unknown. A cradle-to-farm gate life cycle assessment (LCA) was conducted according to international standards (ISO 14040/44), analyzing the impacts of CS representing five different meat sheep production systems in California, and focusing on carbon footprint (carbon dioxide equivalents, CO2e) and irrigated water usage (metric ton, MT). This study is the first to look specifically at the carbon footprint of the California sheep industry and consider both wool and meat production across the diverse sheep production systems within California. This study also explicitly examined the carbon footprint of hair sheep as compared with wooled sheep production. Data were derived from producer interviews and literature values, and California-specific emission factors were used wherever possible. Flock outputs studied included market lamb meat, breeding stock, 2-d-old lambs, cull adult meat, and wool. Four different methane prediction models were examined, including the current IPCC tier 1 and 2 equations, and an additional sensitivity analysis was conducted to examine the effect of a fixed vs. flexible coefficient of gain (kg) in mature ewes on carbon footprint per ewe. Mass, economic, and protein mass allocation were used to examine the impact of allocation method on carbon footprint and water usage, while sensitivity analyses were used to examine the impact of ewe replacement rate (% of ewe flock per year) and lamb crop (lambs born per ewe bred) on carbon footprint per kilogram market lamb. The carbon footprint of market lamb production ranged from 13.9 to 30.6 kg CO2e/kg market lamb production on a mass basis, 10.4 to 18.1 kg CO2e/kg market lamb on an economic basis, and 6.6 to 10.1 kg CO2e/kg market lamb on a protein mass basis. Enteric methane (CH4) production was the largest single source of emissions for all CS, averaging 72% of total emissions. Emissions from feed production averaged 22% in total, primarily from manure emissions credited to feed. Whole-ranch water usage ranged from 2.1 to 44.8 MT/kg market lamb, almost entirely from feed production. Overall results were in agreement with those from meat-focused sheep systems in the United Kingdom as well as beef raised under similar conditions in California.

Estimation of genetic parameters and comparison of breeding values for body weight with different models in a South African Merino stud

Data collected on body weight from birth to 5 years of age in the Grootfontein Merino stud from 1968 to 2012 were analysed with univariate, multivariate and repeatability animal models. The estimated breeding values (EBVs) were compared to determine the most suitable statistical models for the estimation of EBVs. Measures of body weights included birth weight (BW), body weight at 42 days of age (W42), weaning weight (WW), body weight at 6 months (W6), 8 months (W8), 12 months (W12) and 15 months (W15) of age as well as adult weights recorded on the ewe flock from 2 to 5 years of age (AW2 to AW5). Univariate direct heritabilities were 0.20, 0.42, 0.16, 0.54, 0.43, 0.37, 0.51, 0.43, 0.40, 0.31 and 0.33, respectively. Multivariate direct heritabilities for WW, W12, W15 and AW3 were lower than those estimated with univariate models, namely 0.17, 0.22, 0.23 and 0.29, respectively. Direct heritability obtained with the repeatability model was 0.26. Maternal heritabilities for BW, W42, WW, W6, W8, and W15 were 0.11, 0.15, 0.04, 0.28, 0.18 and 0.08, respectively. Lower multivariate maternal heritabilities were obtained for WW (0.02) and W15 (0.01). The genetic correlation between direct and maternal effects was negative for all weights where it was included, ranging from −0.28 for BW to −0.95 for W6. High genetic correlations were estimated between weights at different ages with multivariate analyses. When animals were selected on EBVs estimated with multivariate models, 92% of the animals selected retained the same ranking. When using the Top 1% lists, 95% and 94% of the animals selected on either univariate (U) or multivariate (M) EBVs for W15 and WW respectively, would be identical. Selection based on univariate W15 EBVs would possibly result in selection of different animals, due to lower rank correlations of W15U with WWU (0.67) and WWM (0.80), respectively. The moderate to high estimates of heritability for body weight demonstrated that there is still considerable additive genetic variation in body weight available. The present study indicated that the multivariate model was the most appropriate model for estimating breeding values for body weight at selection age in the Grootfontein Merino stud.

Influence of Male to Female Ratio on Hormone Profiles and Reproductive Performance of Anestrus Postpartum Ewes Subjected to the Male Effect

Background: Complete isolation of genders allows intense estrous induction and synchronization once rams are introduced in ewe flocks at the onset of the breeding season (BS). This management practice, defined as the male effect, results from a neuroendocrine process mediated by pheromones. The male effect is a straightforward procedure to induce estrous in noncycling ewes, but conditions for its use have not been fully explored. Thus, this study aimed to evaluate hormone levels and ovarian activity of postpartum ewes in anestrus which are subjected to the male effect under different male to female ratios.Material, Methods &amp; Results: Pospartum females were selected according to body condition score and cyclicity status. Females were kept apart from males during 30 days at a distance of 10 m. Anestrus and ovulation were determined by P4 measures on days 10, 20 and 30 after isolation from males. After P4 concentration diagnosis, anestrus ewe (n = 99) were subjected to male to ewe ratios (MFR) of 1:20 (MFR20), 1:30 (MFR30) and 1:40 (MFR40). Santa Inês rams (n = 3) of proven fertility were used. Three females of each group were randomly subjected to blood collection for LH concentration analysis. Ovarian activity was performed by ultrasonography after estrus manifestation in six ewe of each group. Estrus events were observed twice a day during the BS of 35 days, and estrus were considered synchronized when it occured within the initial five days of the BS. Pregnancy diagnosis was performed by ultrasonography on days 35 and 60 after the last mating. All ewe were in a non-cycling condition before BS onset, based upon P4 analysis. After initiation of the BS, P4 concentrations increased for all groups. Irrespectively of male to female ratio, male effect induced LH pre-ovulatory peaks within the initial 26 to 86 h of the BS. Synchronization of estrus reached 50% for MFR20, 40% for MFR30 and 20% for MFR40 for all ewe. Moreover, overall estrus incidence was 100% (MFR20), 90% (MFR30) and 65% (MFR40) within the initial 15 days of the BS. However, incidence of ewe that had repeated estrus events was lower for MFR20 than for MFR30. Follicular growth and number of ovulations was similar between groups. Conception rates on first service was higher than that of second service for MFR20 and MFR30, although there was no difference between services for MFR40. In contrast, overall conception rates, delivery type and prolificacy were similar between groups.Discussion: P4 increased to cyclicity levels after contact between genders, demonstrating the potential of the male effect to induce estrus in non-cycling ewes. Most ewe ovulated within three days after the male effect, possibly due to elevated basal LH levels. Moreover, the LH preovulatory peak varied within groups, possibly due to greater interactions between genders, which ultimately may have led to earlier ovulation anticipation under lower MFR. Estrus parameters were similar between groups, suggesting low or negligible effects of MFR. Ovulatory follicle size and growth and the number of ovulations were similar between all groups; previous reports have suggested that this may be due to a strong effect of their genetic background. Conception rates were higher at first than second services, demonstrating the potential of male effect. In conclusion, male to female ratio affects the efficiency of the male effect to induce and synchronize estrus in ewes under postpartum anestrus, but it does not affect conception rates and prolificacy.

Impacts of using a precision livestock system targeted approach in mountain sheep flocks

Although mountain sheep systems suffer from climatic and environmental handicaps that constrain productivity and economic viability, they have an important economic role, maintain habitats and species of high nature conservation value and support the provision of a range of ecosystem services of benefit to society. Using Precision Livestock Farming (PLF) in extensive mountain sheep systems could bring benefits for animal performance, economical performance and labour. This paper presents results from a 3 year experiment where PLF principles were implemented on an extensive mountain sheep farm and an assessment made of whether or not such an approach could benefit more marginal sheep systems. A 900 ewe flock (600 Scottish Blackface ewes, 300 Lleyn ewes) was divided equally into two separate systems, one where the flock was managed conventionally (CON) at group level, and the other where the individuals in the flock were subjected to a PLF management protocol where electronic weighing, recording and drafting equipment were used, linked to the electronic identification (EID) tags of the animals. Two main management strategies were compared and contrasted; one relating to winter feeding of the pregnant ewes, the other relating to anthelmintic treatment of lambs during the summer. Yearly labour profiles were created by measuring the time spent doing individual tasks associated with the two management systems. Net margins (£/ewe) were calculated for the two systems. Additionally, the yearly labour profiles were scaled-up using commercial data to quantify potential labour savings on more traditionally managed mountain farms if PLF principles were adopted. Analyses indicated that the two different management systems did not result in any significant difference in terms of ewe weights, mid-pregnancy scanning figures, ewe and lamb mortality rates, or lamb weight post-weaning. However, the proportion of lambs needing anthelmintic treatment was significantly reduced by 40% between the CON and the PLF, resulting in a reduction of 46% in the amount of anthelmintic used. Over a whole year, the total amount of labour required in the PLF management system was reduced by 36%. Across the 3 years, the net margin for the two systems showed an average difference of £3/ewe higher in the PLF. For a more traditional farm embracing a PLF approach, analyses suggested labour reduction of 19%, equating to £1.60/ewe savings. This study shows that it is beneficial for farmers to consider managing a mountain ewe flock at an individual rather than at flock or batch level using PLF technology.

Evaluation of production and reproduction of three South African Angora goat &lt;i&gt;CYP17&lt;/i&gt; genotypes

Two CYP17 genes, located on different loci and expressing enzymes with significantly different activities, have been identified in the South African Angora goat population. Three unique genotypes (named H e , H u , and H o ), which differed not only in the genes encoding CYP17 , but also in copy number were subsequently identified in the Angora goat. The aim of this study was to evaluate the production and reproduction performance of these three genotypes. Bodyweight, fleece and reproduction data, and blood samples from 466 Angora ewes from three flocks were obtained from the GADI-Biobank. Data had been collected on Flock 1 from 2000 to 2015, Flock 2 from 2000 to 2014 and Flock 3 from 2000 to 2010. Bodyweight data included birth weight, weaning weight, 8-, 12-, and 16-month bodyweight, as well as bodyweight recorded annually for the ewe flock before mating. Fleece data included fleece weight and fibre diameter recorded at the second and third shearings at 12 and 18 months old, respectively. Fleece weight, fibre diameter, style and character were also recorded annually for the ewe flocks during the winter shearing. Individual reproduction records included information on whether the ewe had kidded, whether the ewe had aborted, number of kids born, stillborn kids, kids that died soon after birth, kids reared by a foster mother, kids reared as orphans, number of kids weaned and total weight of kids weaned. Total lifetime reproductive performance of genotyped ewes was calculated for number of kids born, number of kids weaned, and total weight of kids weaned. Blood samples were also collected from 100 sexually active Angora rams from four sources. CYP17 genotyping was carried out using an ARMS-qPCR (amplification refractory mutation system qPCR) assay. Serum testosterone was quantified using high performance liquid chromatography mass spectrometry. The distribution of the ewes across the three CYP17 genotypes was 36.7% H e , 51.5% H u , and 11.8% H o , and was in accordance with the distribution of the Angora veld rams (38.0% H e , 46.4% H u , and 15.6% H o ). In this study, animals of the H u genotype were heavier from weaning age onwards, although this difference in bodyweight was significant only at 8 months old and in the adult ewes. No differences were observed between the H e and H o animals. Adult ewes of the H e genotype (1.35 kg) produced heavier ( P 0.05). No significant differences were recorded in reproductive performance among the genotypes, although the H o ewes had the lowest (1.03 and 0.89) and the H e ewes the highest (1.07 and 0.93) number of kids born and weaned per year respectively. Results on the rams indicated that the CYP17 genotype had no effect on testosterone production by Angora rams. From the results of this study no evidence could be found that selection for any of the three genotypes would adversely affect any growth, mohair production or reproduction function of Angora ewes. A breeding strategy incorporating selection for productive traits and the CYP17 genotype, aimed at increasing the frequency of the ACS+ gene and thus the He genotype in the population, could be followed without having a negative effect on the genetic progress of productive traits. Keywords: Bodyweight, fleece weight, number of kids weaned, testosterone, weight of kids weaned

Progesterone concentration and lambing rate of Karakul ewes treated with prostaglandin and GnRH combined with the ram effect during breeding and non-breeding seasons

The combination of ram effect with two injections of PGF2α 10-days apart and the same protocol plus an additional injection of GnRH prior to the first injection of PGF2α were examined in Karakul ewes during breeding and non-breeding seasons, respectively. Plasma progesterone (P4) concentrations (to detect the presence of active corpus luteum), twin lambing, litter size and synchronization of lambing were evaluated. In each study 70 ewes (2–4 years old) were divided to a treatment (n = 40) and a control (n = 30) group. During the breeding season, on days −10 and 0 before ram release, the treatment group was injected intramuscularly with PGF2α (D-Cloprostenol; 0.15 mg). During the non-breeding season, on day −15 before ram release the treatment group was injected with GnRH (buserelin; 4.2 μg) intramuscularly followed by two injections of PGF2α on days −10 and 0. In both studies, the rams were released into the ewe flock after the second prostaglandin injection (day 0). Blood samples of ewes were collected on days −10, 0, 20 and 70 of the study in breeding season and on days −15, −10, 0, 20 and 70 during non-breeding season. The treatment group had higher P4 concentrations compared to the control ewes on day 0 in the breeding season (5.80 ± 0.61 vs. 5.0 ± 0.93 ng/mL) and day −10 in the non-breeding season (3.50 ± 0.33 vs. 2.70 ± 0.35 ng/mL) though the differences were not significant (P > 0.05). Based on plasma P4 concentrations (>1 ng/mL) on day 70, in the breeding season all control ewes (100%) and 91.9% of the treatment ewes were detected to have active corpus luteum (P = 0.09). An almost inverse result (90% vs. 97.5%; P = 0.2) was detected in the non-breeding season. The lambing rate was higher (P = 0.03) in the treatment group compared to the control ewes during the non-breeding season (90% vs. 70%), but tended to be lower (P = 0.07) in the breeding season (73% vs. 90%). Twin lambing rate was higher in the treatment group compared to the control ewes in the breeding (40.7% vs. 0.0%; P < 0.05) and non-breeding (22.2% vs. 0.0%; P < 0.05) seasons. The litter size of the control and treated ewes were 1.0 ± 0.0 vs. 1.40 ± 0.10 in the breeding and 1.0 ± 0.0 vs. 1.22 ± 0.10 in the non-breeding season (P < 0.05). No effect was observed regard to synchronization of the treated ewes. In the breeding season two injections of PGF2α ten days apart combined with ram effect, may lower the lambing rate, but may enhance twin pregnancies and litter size in Karakul ewes. In the non-breeding season, however, the GnRH-PGF2α treatment plus ram effect may enhance the lambing rate, twin pregnancies and litter size.

Performance loss and changes in behaviour caused by footrot

Two flocks of ewes with lambs were compared for differences in performance. One group was permanently infected with footrot, the other one served as healthy control. They were kept in the same barn but in different bays during lambing and on pasture during the summer. Biweekly all animals were weighed and in the affected group all feet were scored for severity of footrot and if necessary the claws were treated. Furthermore the body condition was scored 4 times in the ewes. The lambs were slaughtered with 43 kg. At that time age and carcass quality were used as parameters. In 20 lambs of each group the lying behaviour was measured using a datalogger during 5 consecutive days. The results revealed significant differences in the performance of ewes and lambs between the two groups. The overall duration of fattening was 31.8 days longer in affected animals. Most importantly, even mild footrot led to significantly impaired growth of the lambs and an altered lying behaviour compared to the healthy controls. The lying periods were more frequent but of shorter duration in affected lambs.

Factors affecting ewe performance in a crossbred dairy sheep research flock in the United States.

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 ( < 0.01) 180d MY, 180d FY, 180d PY, %F, and %P and higher ( < 0.001) LSCS than ewes that had their lambs removed shortly after parturition. Relative to nondairy breeding, EF and LA breeding had positive ( < 0.001) effects on 180d MY, 180d FY, and 180d PY, but a negative ( < 0.03) effect on %P. Purebred EF ewes were predicted to have lower ( < 0.001) %F than purebred LA or nondairy ewes. Purebred LA ewes were predicted to have a higher ( < 0.001) LSCS than purebred EF or nondairy ewes. Purebred EF ewes were expected to be more ( < 0.001) prolific than purebred LA or nondairy ewes. Individual retained heterosis had a favorable ( < 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.

Winter grazing and dead material effects on early spring pasture production

ABSTRACTImproved performance of the national ewe flock along with the displacement of finishing farms into hill country has increased pressure on spring pasture production. Increasing spring pasture production to cope with this increased demand is considered one of the main areas of improvement needed in hill country farming. A trial was set up in the South Island of New Zealand to determine the response of spring pasture production to two winter grazing intensities across three levels of sward dead material. Total spring pasture production was unaffected by winter grazing intensity. Winter dead material levels significantly affected total spring pasture production. Plots with high dead material levels (>60%) grew 657 kg DM/ha less than plots with low dead material levels (<30%) over the spring period. Reducing the amount of dead material in the sward is recommended as the shading of grass tillers by dead material reduces growth of new pasture.

Modelling gastrointestinal parasitism infection in a sheep flock over two reproductive seasons: in silico exploration and sensitivity analysis.

In reproducing ewes, a periparturient breakdown of immunity is often observed to result in increased fecal egg excretion, making them the main source of infection for their immunologically naive lambs. In this study, we expanded a simulation model previously developed for growing lambs to explore the impact of the genotype (performance and resistance traits) and host nutrition on the performance and parasitism of both growing lambs and reproducing ewes naturally infected with Teladorsagia circumcincta. Our model accounted for nutrient-demanding phases, such as gestation and lactation, and included a supplementary module to manage the age structure of the ewe flock. The model was validated by comparison with published data. Because model parameters were unknown or poorly estimated, detailed sensitivity analysis of the model was performed for the sheep mortality and the level of infection, following a preliminary screening step. The parameters with the greatest effect on parasite-related outputs were those driving animal growth and milk yield. Our model enables different parasite-control strategies (host nutrition, breeding for resistance and anthelmintic treatments) to be assessed on the long term in a sheep flock. To optimize in silico exploration, the parameters highlighted by the sensitivity analysis should be refined with real data.

Computer modelling of anthelmintic resistance and worm control outcomes for refugia-based nematode control strategies in Merino ewes in Western Australia

This study utilised computer simulation modelling (Risk Management Model for Nematodes) to investigate the impact of different parasite refugia scenarios on the development of anthelmintic resistance and worm control effectiveness. The simulations were conducted for adult ewe flocks in a Mediterranean climatic region over a 20 year time period. Factors explored in the simulation exercise were environment (different weather conditions), drug efficacy, the percentage of the flock left untreated, the timing of anthelmintic treatments, the initial worm egg count, and the number of drenches per annum. The model was run with variable proportions of the flock untreated (0, 10, 20, 30, 40 and 50%), with ewes selected at random so that reductions in the mean worm burden or egg count were proportional to the treated section of the flock. Treatments to ewes were given either in summer (December; low refugia potential, hence highly selective) or autumn (March; less selective due to a greater refugia potential), and the use of different anthelmintics was simulated to indicate the difference between active ingredients of different efficacy. Each model scenario was run for two environments, specifically a lower rainfall area (more selective) and a higher rainfall area (less selective) within a Mediterranean climatic zone, characterised by hot, dry summers and cool, wet winters. Univariate general linear models with least square difference post-hoc tests were used to examine differences between means of factors. The results confirmed that leaving a proportion of sheep in a flock untreated was effective in delaying the development of anthelmintic resistance, with as low as 10% of a flock untreated sufficient to significantly delay resistance, although this strategy was associated with a small reduction in worm control. Administering anthelmintics in autumn rather than summer was also effective in delaying the development of anthelmintic resistance in the lower rainfall environment where all sheep were treated, although the effect of treatment timing on worm control effectiveness varied between the environments and the proportion of ewes left untreated. The use of anthelmintics with higher efficacy delayed the development of resistance, but the initial worm egg count or number of annual treatments had no effect on either the time to resistance development or worm control effectiveness. In conclusion, the modelling study suggests that leaving a small proportion of ewes untreated, or changing the time of treatment, can delay the onset of anthelmintic resistance in a highly selective environment.