Commercial Sheep Farms Research Articles

Resistance of Gastrointestinal Nematodes to Anthelmintics in Sheep Production in Zimbabwe

Introduction: Sheep play a crucial role in enhancing the socio-economic welfare of individuals in numerous nations. Within sub-Saharan Africa, productivity levels are hindered by various factors, such as prevalent diseases, inadequate nutrition, climate variations, predators, severe weather, as well as infestations of both external and internal parasites. The purpose of the present study was to assess the extent of anthelmintic resistance (AR) observed on a sheep farm operating for commercial purposes in Zimbabwe. Materials and methods: Forty female weaner Dorper sheep, averaging 43 kg in body weight, were selected from Ballineety commercial sheep farm in Mashonaland Central, Zimbabwe. These sheep were then divided into four groups of ten each, receiving different treatments including ivermectin, albendazole, levamisole, and no treatment as a control. Each treatment was administered according to the manufacturer’s recommendations. Pre-treatment faecal samples (day zero) and post-treatment (day 14) were collected and subjected to the Faecal Egg Count Reduction Test (FECRT). Anthelminthic resistance was suggested (AR) by the presence of faecal eggs after treatment. Results: All the drugs indicated a decrease in egg counts by less than 90%. The effectiveness of ivermectin, albendazole, and levamisole was measured at 58.5%, 70.1%, and 85.8% respectively. These findings indicate that nematodes have developed resistance to all treatments. The larval cultures of the samples before and after treatment indicated a significant presence of Haemonchus spp. in the pooled samples. In contrast, the quantities of Trichostrongylus spp. and Oesophagostomum spp. were low but present in all treatments. Cooperia spp. was recovered in post-treatment larval cultures of groups that received anthelmintic. The present study reports lower-than-expected efficacy for ivermectin, albendazole, and levamisole based on the reduction of egg excreted post-treatment. Conclusion: A common worms population in sheep are AR in the current study area. Therefore, comprehensive nematode management programs along with complementary eradication strategies are essential for sustainable sheep production.

Sheep welfare assessment of meat farms from Spain in different breeds and production systems

Sheep production systems are diverse in Europe, and welfare assessment should consider this diversity, including differences in breed type, climatic conditions, and time of the year. The aim of this study was to evaluate welfare in 100 commercial sheep farms in Spain, and therefore in Mediterranean conditions, using a list of 24 indicators, comprising three for good feeding, five for housing, 11 for health, and five for appropriate behavior. The list includes indicators from the AWIN protocol and other suggested indicators. Level of intensification was the main parameter that affected the welfare outcomes of feeding and health, but seasonality and flock size also affected some of the outcomes. Novel indicators included in the list (sternum evaluation, crowding behavior, subcutaneous abscesses, external parasitism, aggressive behaviors, wool pulling, ear posture, and reaction during restraint) were useful to evaluate welfare in Spanish farming conditions, but further studies should be performed to validate these indicators.

Non-genetic factors affecting litter size, age at first lambing and lambing interval of Romanov sheep in Croatia

Reproductive traits are of paramountimportance in an efficient lamb production system. In Croatia, values of reproductive traits of Romanov sheep are below the average expected for this breed, indicating the need for improvement of these traits to exploit the breed’s full reproductive potential. This study was conducted on 260 Romanov ewes located at a commercial Romanov sheep farm in Croatia. All ewes were kept under similar conditions, and reproductive management was based on accelerated lambing with continuous mating. Linear models with fixed effects were used to estimate the influence of year of birth/lambing, season of birth/lambing, ram, parity and litter type on litter size (LS), age at first lambing (AFL) and lambing interval (LI). Average LS was 2.11 ± 0.71, while the year of lambing and parity were the most important factors affecting this trait. The smallest litters were recorded after 1st parity (1.77 ± 0.06), and the largest after 5th parity (2.21 ± 0.08). AFL averaged 388.5 ± 72.4 days. All investigated non-genetic factors had a significant (P<0.05) influence on AFL, with year of birth as most important. The average LI was 241.2 ± 70.8 days. A significant (P<0.05) influence of all factors on LI was observed. Ewes lambing in spring (200.2 ± 7.9 days) or summer (190.5 ±6.6 days) had a significantly (P<0.05) shorter LI than ewes lambing in autumn (227.7 ± 8.3 days) or winter (237.2 ± 6.7 days). The longest LI was observed after the first parity (284.0 ±5.5 days). Average values for reproductive traits in the examined population of Romanov sheep were higher than those reported in the official Croatian database for breeding sheep. Non-genetic factors have a significant influence on the variation of reproductive traits of Romanov sheep, and therefore should be considered when assessing ewes’ reproductive performance.

The production costs of Haemonchus contortus and other nematode parasites in pre-weaned beef calves in New Zealand.

Haemonchus contortus can frequently be found infecting pre-weaned beef calves on sheep and beef farms around the North Island of New Zealand. The purpose of this study was to consider whether the presence of this parasite alone, or as part of a mixed infection, could be impacting growth rates of young animals, on three commercial farms in the North Island of New Zealand. Trials were conducted on commercial sheep and beef farms in each of the Northland, King Country and Gisborne regions, in late summer/autumn (February to April) of 2016 to measure the effect of treatment with narrow and broad spectrum anthelmintics on liveweight gain of spring-born calves pre-weaning. Each farm was chosen based on the presence of Haemonchus and that it was a beef cow/calf system with the cows and calves grazing the same pastures as sheep at some stage. Three sampling visits were made to each farm with the animals being weighed, faecal sampled and treated with one of two anthelmintics (Closantel alone to remove only Haemonchus or a triple combination containing moxidectin, levamisole and oxfendazole to remove all nematodes) or left untreated, on each of the first two visits. There was no significant difference in liveweight gain between any of the treatment groups, hence there was no evidence for an impact of Haemonchus alone, or a mixed nematode infection, on pre-weaned calf growth rates on these farms. It remains unclear whether there may be a justification to consider treatment of calves should they constitute a significant source of pasture larval infestation with H. contortus, in an integrated cattle-sheep system.

Ewe colostrum quality on commercial Welsh sheep farms

In advance of the 2020 lambing season, 147 Welsh farmers were engaged in active colostrum management through training and discussion groups. Sixty-four of these farmers returned data on 1295 ewes, including ewe age, breed, body condition score (BCS), number of live and dead lambs born, a description of udder condition, colour of colostrum and a Brix reading. Flock numbers were available from 43 farmers and information on late pregnancy ration from 30 farms. Results were analysed using a Brix reading cut-off of 26.5% and showed that 76% of samples exceeded this level and were considered of good quality. With an average of 20 ewe colostrum samples returned per flock, the greatest variation was found to be at the flock level with ewe nutrition considered to be the greatest driver. Concentrate feed space, silage crude protein and the supplementation of concentrates to twin and triplet-bearing ewes were all factors that indicated a potential flock level role in determining the colostrum quality. Individual level ewe factors appeared to have a much smaller role in determining the quality of the colostrum, with the ease of stripping being the main significant factors. Colostrum quality was more likely to be inadequate if the ewe was reported to be hard to strip (OR 0.56). While not significant in the final regression model, other ewe factors appeared to have an impact on the colostrum quality, such as the BCS and number of lambs born; however, lack of significance in the model may mean they are not significant or that they reflect differences in management between different flocks. As UK sheep farmers prepare for lambing 2022, and continue to optimise colostrum management and reduce levels of antibiotic given to neonatal lambs, this practical study has demonstrated how sheep farmers can be actively motivated to measure colostrum quality to determine how to optimally manage colostral antibody delivery to individual lambs.

Comparison between methods for measuring fecal egg count and estimating genetic parameters for gastrointestinal parasite resistance traits in sheep.

Fecal egg count (FEC) is an indicative measurement for parasite infection in sheep. Different FEC methods may show inconsistent results. Not accounting for inconsistencies can be problematic when integrating measurements from different FEC methods for genetic evaluation. The objectives of this study were to evaluate the difference in means and variances between two fecal egg counting methods used in sheep—the Modified McMaster (LMMR) and the Triple Chamber McMaster (LTCM); to estimate variance components for the two FEC methods, treating them as two different traits; and to integrate FEC data from the two different methods and estimate genetic parameters for FEC and other gastrointestinal parasite resistance traits. Fecal samples were collected from a commercial Rideau-Arcott sheep farm in Ontario. Fecal egg counting was performed using both LMMR and the LTCM methods. Other parasite resistance trait records were collected from the same farm including eye score (FAMACHA), body condition score (BCS), and body weight (WT). The two FEC methods were highly genetically (0.94) and phenotypically (0.88) correlated. However, the mean and variance between the two FEC methods were significantly different (P < 0.0001). Therefore, re-scaling is required prior to integrating data from the different methods. For the multiple trait analysis, data from the two fecal egg counting methods were integrated (LFEC) by using records for the LMMR when available and replacing missing records with re-standardized LTCM records converted to the same mean and variance of LMMR. Heritability estimates were 0.12 ± 0.04, 0.07 ± 0.05, 0.17 ± 0.06, and 0.24 ± 0.07 for LFEC egg count, FAMACHA, BCS, and WT, respectively. The estimated genetic correlations between FEC and the other parasite resistance traits were low and not significant (P > 0.05) for FAMACHA (r = 0.24 ± 0.32) and WT (r = 0.22 ± 0.19), and essentially zero for BCS (r = −0.03 ± 0.25), suggesting little to no benefit of using such traits as indicators for LFEC.

New Insight into the Prevalence and Risk Factors for Three Distinct Hoof Conformation Traits in UK Commercial Sheep Flocks.

Lameness in sheep continues to be a global health, welfare and economic concern. Damaged, misshapen or overgrown feet have the potential to cause lameness either directly, or indirectly. There is a lack of understanding of the predisposing factors for different hoof conformation traits in sheep. Our exploratory study aimed to investigate the prevalence of, and risk factors for, three distinct hoof conformation traits relating to the sole and heel, hoof wall, and hoof wall overgrowth. Feet of 400 ewes from four UK commercial sheep farms were inspected at four time points across 12 months. For each conformation trait, a four-point ordinal system was used to score each individual claw, and foot-level scores were calculated. We present 92.4% of foot-level observations to be affected by ≥1 conformation traits. Whilst hoof conformation traits were correlated to some degree, a unique set of sheep-, foot- and farm-level factors were associated with each distinct conformation trait. We provide, for the first time, key insight into the multifaceted and multifactorial aetiology of hoof conformation in sheep, building upon previous landmark studies. Our results inform hypotheses for future prospective studies investigating the risk factors for adverse hoof conformation in sheep.

Prevalence and Temporal Dynamics of White Line Disease in Sheep: An Exploratory Investigation into Disease Distribution and Associated Risk Factors.

Lameness in sheep is a global health, welfare and economic concern. White line disease (WLD), also known as shelly hoof, is a prevalent, non-infectious cause of lameness, characterised by the breakdown of the white line. Little is known about the predisposing factors, nor the individual disease dynamics over time. Our exploratory study aimed to investigate the prevalence and temporal dynamics of WLD, and the associated risk factors. Feet of 400 ewes from four UK commercial sheep farms were inspected for WLD at four time points across 12 months. The change in WLD state at foot-level (develop or recover) was calculated for three transition periods. We present WLD to be widespread, affecting 46.8% of foot-level and 76.6% of sheep-level observations. States in WLD changed over time, with feet readily developing and recovering from WLD within the study period. The presence of WLD at foot-level, the number of feet affected at sheep-level and dynamics in development and recovery were driven by a variety of foot-, sheep- and farm-level factors. We provide key insight into the multifaceted aetiology of WLD and corroborate previous studies demonstrating its multifactorial nature. Our study highlights an opportunity to reduce WLD prevalence and informs hypotheses for future prospective studies.

The effect of pasture molluscicide on small lungworm infections and the productivity of grazing lambs

The aim of this study was to assess the effect of pasture molluscicide treatment on the prevalence and severity of small lungworm infections, and the productivity of lambs grazing improved pastures in southeastern Australia. A randomised control field trial of 260 Merino-cross lambs was conducted on a commercially managed farm in South Australia with a history of high small lungworm prevalence. Separate groups of lambs rotationally grazed irrigated lucerne paddocks treated with iron chelate molluscicide or untreated control paddocks. Lambs were monitored every 2–6 weeks from weaning until slaughter with liveweight, lungworm and gastrointestinal nematode infection status measured. At slaughter indicators of small lungworm infection via inspection and carcass characteristics were assessed. The density of the intermediate host snail and lucerne pasture availability were also measured. There was a higher population of adult Prietocella barbara molluscs in the Control paddocks compared to the Treatment paddocks after molluscicide had been applied and prior to grazing commencing (206 vs. 14 snails/m2, respectively; P = 0.03; 95 % CI 8, 528). However, the overall mollusc density was similar between Control and Treatment. The prevalence of small lungworm infections was quite low during the trial (0–13 %), in both Control and Treatment lambs, except at day 94 when 48 % of 28 Control lambs were positive compared to none of 27 Treatment lambs (P < 0.001; 95 % CI 30, 66). A similar proportion of Treatment and Control lambs had evidence of small lungworm infection lesions at slaughter (both 67.8 %). Control lambs grew slightly faster than Treatment lambs, with an average daily gain of 202 (± 3 SEM) g/head/day for Control and 190 (± 4 SEM) for Treatment (P < 0.001) during the 112-day trial.Despite historic evidence of very high prevalence of lungworm infection in this region of southeastern Australia, iron chelate molluscicide treatment prior to lambs grazing the pasture had no demonstrable effect on the prevalence and severity of small lungworm infections, nor the productivity of lambs grazing these pastures. This study indicates that for a commercial sheep farm, additional molluscicide treatments of pastures after they are established, for the prevention of small lungworm infection, may not be warranted. Furthermore, requirements for more precisely monitoring snails are discussed.

Anthelmintic resistance in commercial sheep farms in Costa Rica.

Forty-eight commercial sheep farms were sampled between the years 2017 and 2019 to evaluate the percentage of reduction of the three families of broad-spectrum anthelmintic drugs available in Costa Rica - benzimidazoles (albendazole), macrocyclic lactones (ivermectin) and imidazothiazoles (levamisole) - in grazing animals by using the fecal egg count reduction test. Animals were selected based on their egg per gram counts after their fecal samples were processed by a modified McMaster technique. The remaining fecal samples were taken to the laboratory for fecal culture and larval identification. The prevalence of farms with albendazole resistance was 100%, ivermectin 96% and levamisole 17%. Seven (n=47) farms resulted with triple resistance, 39 with double and 1 farm was resistant to 1 AH tested. Haemonchus spp. was the most commonly isolated parasite in pre- and post-treatment larval culture. This is the first report of Oesophagostomum spp. and Teladorsagia sp. resistant to albendazole, Oesophagostomum spp., Teladorsagia sp., Chabertia sp. and Cooperia sp. resistant to ivermectin, and the presence of strains of Haemonchus spp. and Trichostrongylus sp. resistant to the 3 anthelmintics tested. The results of this study demonstrate that anthelmintic resistance is widespread, particularly in Haemonchus spp., and that the major drugs available in the country have lost much of their effectiveness against sheep nematodes.

Iceberg Indicators for Animal Welfare in Rural Sheep Farms Using the Five Domains Model Approach.

Simple SummaryAnimal welfare is difficult to quantify, especially among farmers, in extensive rural sheep farms where there is a low level of animal interaction and a lack of technology. In this study, we searched for iceberg indicators of animal welfare using the Five Domains Model approach, and studied the relationship among sheep flight distance, sheep handling training and job satisfaction in extensive rural sheep systems. A structured survey was used to obtain socio-demographical, job satisfaction and sheep handling training data. A full animal welfare evaluation was performed on all farms; furthermore, a health status examination was also made in which blood and stool samples were taken. Four iceberg indicators were found with the potential to predict overall animal welfare scores on farms, and one to study state of mind in extensive rural sheep systems, as well as interactions among job satisfaction, training in sheep handling and sheep mind state.Animal welfare for sheep in extensive rural farms is difficult to quantify among rural farmers due to several factors, including the lack of technology and the low level of interaction they have with the animals. The purpose of this study was to search for animal-based iceberg indicators using the Five Domains Model approach and study the relationship between sheep reactive behavior (flight distance), sheep handling training and farmers job satisfaction. Thirteen extensive commercial dual-purpose sheep farms (n = 520 animals) were evaluated in Marulanda, Caldas (Colombia, South America). On-farm Animal Welfare Indicators (AWIN) were assessed using an adapted version of this protocol. Socio-demographic characteristics, sheep handling training and job satisfaction were evaluated using a structured interview. Blood and stool samples were taken to determine Fecal Egg Count and Packed Cell Volume. Bivariate regression models were used to find animal-based indicators that predicted Nutrition, Ambience, Health and Behavior welfare domains, and a Qualitative Behavior Analysis was used for mind state domain analysis. Body condition score (BCS) (p = 0.001), fleece cleanliness (p = 0.03), FAMACHA© Score (p = 0.05), and flight distance in meters (p = 0.19) were found to be indicators, and were useful for predicting overall welfare assessment (R2 = 0.85) on theses farms. Regarding mind welfare domain, Qualitative Behavioral Assessment found two principal components (PC) that explained 82% and 67% of the variance, and described emotional valence and energy levels of sheep, respectively. Sheep handling training (β = −8.75, p = 0.004) and job satisfaction (β = −7.5, p = 0.013) had a negative association with the average flock flight distance. Spearman’s rank correlations were significant (p < 0.001) between Fecal Egg Count, Packed Cell Volume, FAMACHA© Score (FS), Body Weight (BW) and, BCS. The strongest association was observed between Packed Cell Volume (PCV) and Fecal Egg Count (FEC) (r = −0.43), also FS was correlated with PCV (r = −0.28) and FEC (r = 0.21), and BCS was correlated with weight (r = 0.32). We suggest that these animal-based indicators could be useful as iceberg indicators for extensive sheep production systems and may set the ground for more research in small extensive sheep farms to develop strategies to find welfare problems and solutions.

PSIII-8 Difference between two fecal egg count methods and estimation of genetic parameters for gastrointestinal parasite resistance traits in sheep

Abstract Fecal egg count (FEC) is an indicative measurement for parasite infection in sheep. Different FEC methods may show inconsistent results. Not accounting for inconsistencies can be problematic when integrating measurements from different FEC methods for genetic evaluation. The objectives of this study were to: evaluate the difference between two FEC methods, the Modified McMaster (LMMR) and the Triple Chamber McMaster (LTCM); estimate the genetic and phenotypic correlations between records from two methods; and estimate genetic parameters for FEC and other gastrointestinal parasite resistance traits. A total of 1,676 fecal samples were collected from a commercial sheep farm between 2012 and 2019. Fecal egg counting was performed using the Modified McMaster (n = 998) and the Triple Chamber McMaster (n = 678) methods. Other parasite resistance trait records were collected from the same farm including eye score (FAMACHA©), body condition score (BCS), and body weight (WT). The mean and variance between the two FEC methods were significantly different (P &amp;lt; 0.0001), but phenotypic and genetic correlations between them were high (0.88 and 0.94, respectively). Therefore, pre-adjustment is required prior to integrating data from the different methods. For multiple trait analysis with other parasite resistance traits, data from the two fecal egg counting methods were integrated (LFEC) by using records for the LMMR when available and replacing missing records with standardized LTCM records for mean and variance of LMMR. Heritability estimates were 0.12, 0.07, 0.17, and 0.24, for LFEC, FAMACHA©, BCS, and the WT, respectively. Estimated genetic correlations between fecal egg count and the other parasite resistance traits were low with FAMACHA© (0.24), BCS (-0.03), and WT (0.22), suggesting little to no benefit of using such traits as indicators for LFEC.

Variation in hatching responses of Nematodirus battus eggs to temperature experiences

BackgroundNematodirus battus, unlike most other gastrointestinal nematodes, undergoes maturation to an infective larva within the egg. Historically, eggs were considered to require a period of chilling over winter followed by a period of temperature above 10 °C for synchronous hatching to occur (generally in spring). Anecdotal reports of Nematodirus infection out-with spring in veterinary journals and the farming press suggest that the concentrated pasture abundance of N. battus infective larvae may be changing. In order for control practices to be adapted, and unexpected disease outbreaks to be avoided, it is important to quantify how parasite epidemiology is changing and research the drivers behind it.MethodThe present study investigated the in vitro hatching response to temperature experiences (with and without a period of chilling) for egg samples of 90 N. battus populations obtained from 73 commercial sheep farms. Six aliquots of larvated eggs were prepared per population, three aliquots were placed at 4 °C for 6 weeks to provide a chill stimulus then incubated at the optimal hatching temperature for the species. The remaining three aliquots of eggs were incubated at the hatching temperature without a prior chill stimulus and the number of hatched larvae was compared between treatments.ResultsMedian hatch rate across all populations with chilling was 45% (95% CI: 42–48%) and without chilling was 4% (95% CI: 2–6%). Inter-population variation in hatching ranged from 0 to 87% of eggs able to hatch in the absence of a chill stimulus, mean non-chill hatching was 13 ± 2% of eggs (mean ± SE). Non-chill hatching rates were greater than chilled hatching rates in seven of the 90 populations tested.ConclusionsClearly, the variation in hatching responses to temperature experience is very large and therefore the seasonality of the parasite may vary not only between regions but also at farm level. In contrast to what previous work has suggested, there was a geographical trend towards higher non-chill hatching in the Northern parts of the UK.

Prevalence of Salmonella enterica subsp. diarizonae serotype 61:k:1:5:(7) in nasal secretions and stool of sheep flocks with and without cases of chronic proliferative rhinitis

Salmonella enterica subsp. diarizonae serotype 61: k: 1,5, (7) (SED) is a microorganism well adapted to sheep; however, it has also been described producing chronic proliferative rhinitis (CPR) in ovine. CPR causes a proliferative inflammation of the ventral nasal turbinates that may totally obstruct the nasal cavity.The main objective of the present study was to investigate the prevalence of SED in nostrils and stool of sheep without CPR clinical signs in commercial sheep farms of Spain with and without previous clinical cases of CPR.Five samplings were performed in 10 commercial sheep farms for one year. Samples from nostrils and faeces were taken from four animals without CPR visible clinical signs that belonged to four different age ranges at each farm visit.The prevalence of positive animals was 45.3 %, and the number of positive samples in nostrils was higher than in faeces (38.5 % vs 22.5 %). Only on one farm was no positive result obtained in the entire study. In almost all positive farms, sheep belonging to the youngest age ranges accounted for more than 50 % of positive isolates. Finally, farms with a previous diagnosis of CPR were 1.784 times more likely to have an animal with positive isolation than farms without a previous diagnosis. This could suggest that the infection pressure in the farm might favour the occurrence of clinical cases of the disease. However, further studies will be necessary to unravel why this saprophytic bacterium is able to cross the epithelial barrier causing severe rhinitis in certain animals.

Influence of the Ovine Genital Tract Microbiota on the Species Artificial Insemination Outcome. A Pilot Study in Commercial Sheep Farms.

To date, there is a lack of research into the vaginal and sperm microbiome and its bearing on artificial insemination (AI) success in the ovine species. Using hypervariable regions V3–V4 of the 16S rRNA, we describe, for the first time, the combined effect of the ovine microbiome of both females (50 ewes belonging to five herds) and males (five AI rams from an AI center) on AI outcome. Differences in microbiota abundance between pregnant and non-pregnant ewes and between ewes carrying progesterone-releasing intravaginal devices (PRID) with or without antibiotic were tested at different taxonomic levels. The antibiotic treatment applied with the PRID only altered Streptobacillus genus abundance, which was significantly lower in ewes carrying PRID with antibiotic. Mageebacillus, Histophilus, Actinobacilllus and Sneathia genera were significantly less abundant in pregnant ewes. In addition, these genera were more abundant in two farms with higher AI failure. Species of these genera such as Actinobacillus seminis and Histophilus somni have been associated with reproductive disorders in the ovine species. These genera were not present in the sperm samples of AI rams, but were found in the foreskin samples of rams belonging to herd 2 (with high AI failure rate) indicating that their presence in ewes’ vagina could be due to prior transmission by natural mating with rams reared in the herd.

The effect of serum 25-hydroxyvitamin D concentration on fecundity of ewes on a New Zealand sheep farm

Abstract Research on Soay Island sheep showed a positive association of serum 25(OH)D concentration and fecundity, while similar research on Scottish sheep didn’t show an association with fecundity but did show an association with weaned lamb weight. Therefore the aim of this study was to determine if serum 25-hydroxyvitamin D (25(OH)D) concentrations of ewes at mating, on a commercial sheep farm, was associated with subsequent prolificacy. On a sheep and beef farm in the North Island of New Zealand 200 mixed-age Romney ewes (Ovis aries) had weights recorded and blood was collected by jugular venepuncture in April (autumn) at mating. Pregnancy testing was conducted 12 weeks after mating, using real time ultrasound to confirm pregnancy and determine whether the dams were carrying singletons, twins or triplets. Serum 25(OH)D2 and D3 concentrations, total calcium, and phosphorus concentrations were measured in the 200 pregnant ewes. A multinomial logistic regression model was fitted to the data in order to determine significant predictors of the ultrasound scanning result. The mean serum total 25(OH)D concentrations of single, twin and triplet bearing ewes were 102.0 ± 3.4, 101.0 ± 2.4 and 83.0 ± 4.5, respectively. In a multinomial logistic regression model serum total 25(OH)D and 25(OH)D3 concentrations were also negatively correlated with ewes pregnant with triplets (P = 0.015), while weight was significantly associated with both twin and triplet bearing ewes (P The reason for the lower serum 25(OH)D concentration in sheep bearing triplets is unclear, and further research is required in order to determine the mechanisms behind this. The results suggest that an effect on ewe fecundity may only be seen when serum 25(OH)D concentrations are marginal.

Use of bootstrapped, regularised regression to identify factors associated with lamb-derived revenue on commercial sheep farms

The profitability of UK sheep farms is variable with many farms making a net loss. For economic sustainability, farms have to be profitable, therefore it is important to maximise income whilst controlling costs. The most important source of income in sheep flocks is from lamb production but there is little information on factors that explain variability between farms in revenue from lamb sales. The aim of this research was to identify farm, farmer and management factors likely to have the largest, most reliable associations with lamb-derived revenue.From a population of 830 sheep farms, 408 farmers completed an online questionnaire comprising over 300 variables. Total lamb-derived revenue was calculated for each farm using abattoir information including carcass classification. The median flock size was 560 ewes, median land size 265 acres, median revenue per acre from lambs sold was £197 (IQR = 120–296) and median revenue per ewe £95 (IQR = 72–123). A robust analytic approach using regularised (elastic net) regression with bootstrapping was implemented to account for multicollinearity in the data and to reduce the likelihood of model over-fitting. To provide model inference and allow ranking of variables in terms of relevance, covariate stability and coefficient distributions were evaluated.Factors with high stability and relatively large positive associations with revenue per acre were (median effect size (£); 95 % bootstrap probability interval); an increased stocking rate of 0.2 ewe/acre (13; 6–17), fertilizer being used on most of the grazing land (18; 0.1–37), the use of rotational grazing (13; 0.3–34), decreased proportion of ewes with prolapses (4; 0.3–9), separation of lame sheep from the rest of the flock (16; 0.9–37), selecting ewes for culling based on prolapses (20; 0.2–55) and infertility (20; 2–46), conducting body condition scoring of ewes at lambing (28; 3–58), early lactation (21; 1–54) or weaning (25; 2–70), increased farmer education (20; 2–54) and farmers with a positive business attitude (15; 0.2–38). Additional factors with a high stability and relatively large associations with increased revenue per ewe were; never trimming diseased feet of lame ewes (9; 0.8–22) and making use of farm records (5; 0.3–12).This is the first study in animal health epidemiology to use bootstrapped regularised regression to evaluate a wide dataset to provide a ranking of the importance of explanatory covariates. We conclude that the relatively small set of variables identified, with a potentially large influence on lamb-derived revenue, should be considered prime candidates for future intervention studies.

Detection of Toxoplasma gondii infection in semen of rams used for natural mating in commercial sheep farms in Tunisia.

Toxoplasmosis, a parasitic infection, disrupts sexual functions resulting in decline in reproductive and economic performance in sheep. Lacking discernible symptoms, toxoplasmosis is difficult to detect and diagnose in infected animals. Here, to estimate the prevalence of natural infection by Toxoplasma gondii, we used PCR to amplify and detect T. gondii DNA in semen from 92 rams of three breeds from four regions in Tunisia and seroprevalence was determined using a commercial ELISA kit. From the PCR amplifications, 51.09 ± 10.21% of the rams were tested positive for T. gondii with an overall seroprevalence of 39.13 ± 9.97%. Risk factors including ram location and number of accomplished mating seasons significantly (p < .05) affected the sero- and molecular prevalence of T. gondii in semen but, there was a fair concordance between sero- and molecular prevalence (Kappa = 0.33). Sequences of T. gondii from five positive samples were 100% identical (same haplotype). Comparison of these sequences with those archived at the GenBank showed a sequence similarity range between 95 and 100%. The haplotype defining the five Tunisian sequences was similar to the one observed in chicken, cats, European pole cat and humans from Brazil, St Kitts and Nevis, Great Britain and Tunisia, respectively. This indicates its wide geographic distribution and non-species specificity. Our findings suggest a high prevalence of toxoplasmosis in Tunisian matting rams; further studies concerning its venereal transmission capacity are needed prior to recommending a systematic screening of T. gondii DNA in rams' semen used for both natural breeding and artificial insemination.

From the ‘Merino Revolution’ to the ‘Astronomy Revolution’: Land Alienation and Identity in Carnarvon, South Africa

The establishment of an astronomy reserve around the core site of the Square Kilometre Array radio telescope marks the beginning of an epochal shift away from commercial sheep farming in the upper Karoo. In this article, I reflect on the significance of this ‘astronomy revolution’ by exploring the ways in which land is central to dynamics of identification, shaping social hierarchies and development expectations. The article uses archival and ethnographic sources to explore the case of Carnarvon. It contextualises the current land-use change to astronomy in the social history of the town, addressing the set of events that marked an earlier epochal change: the transition from communal to commercial sheep farming, often called the ‘merino revolution’. The history of land alienation accompanying this earlier transition resurfaces in current claims lodged through the post-apartheid land restitution programme, which intersect in complex ways with the current land-use change to astronomy. The article identifies a central tension in the ‘astronomy revolution’, which undermines claims to redress local historical inequalities while promoting identification with a broader national and global development priority.

Designing Successful Land Reform For The Extensive Grazing Sector

The purpose of this paper is to identify the determinants of success in commercial sheep farming in the Karoo so that these characteristics can be designed into smallholder commercialisation programmes there and in the former homelands of the Eastern Cape Province of South Africa. Benchmarking applied to production data from commercial operations revealed that every fifth commercial farmer is less than 50% efficient, and therefore is as much in need of extension as any smallholder might be. Experience is an important determinant of performance and could be developed in the smallholder sector through vocational training at the point of commercialisation. Sheep farming is amenable to smallholder production because it can be done successfully on a part-time basis. Woolled sheep are important. Being able to respond flexibly to rainfall variability is essential, but there are several ways to achieve this cost effectively in the smallholder sector. Keywords: Benchmarks, Extension plans, Extensive grazing areas, Sheep farming