Dorper Sheep Research Articles

Identification of novel loci associated with gastrointestinal parasite resistance in a Red Maasai x Dorper backcross population.

Gastrointestinal (GI) parasitic infection is the main health constraint for small ruminant production, causing loss of weight and/or death. Red Maasai sheep have adapted to a tropical environment where extreme parasite exposure is a constant, especially with highly pathogenic Haemonchus contortus. This breed has been reported to be resistant to gastrointestinal parasite infection, hence it is considered an invaluable resource to study associations between host genetics and resistance. The aim of this study was to identify polymorphisms strongly associated with host resistance in a double backcross population derived from Red Maasai and Dorper sheep using a SNP-based GWAS analysis. The animals that were genotyped represented the most resistant and susceptible individuals based on the tails of phenotypic distribution (10% each) for average faecal egg counts (AVFEC). AVFEC, packed cell volume (AVPCV), and live weight (AVLWT) were adjusted for fixed effects and co-variables, and an association analysis was run using EMMAX. Revised significance levels were calculated using 100,000 permutation tests. The top five significant SNP markers with - log10 p-values >3.794 were observed on five different chromosomes for AVFEC, and BLUPPf90/PostGSf90 results confirmed EMMAX significant regions for this trait. One of these regions included a cluster of significant SNP on chromosome (Chr) 6 not in linkage disequilibrium to each other. This genomic location contains annotated genes involved in cytokine signalling, haemostasis and mucus biosynthesis. Only one association detected on Chr 7 was significant for both AVPCV and AVLWT. The results generated here reveal candidate immune variants for genes involved in differential response to infection and provide additional SNP marker information that has potential to aid selection of resistance to gastrointestinal parasites in sheep of a similar genetic background to the double backcross population.

Effects of behavioral reactivity on production and reproduction traits in Dorper sheep breed

Abstract The aim of the current research was to evaluate the effects of behavioral reactivity on production and reproduction performance in Dorper sheep, a meat breed. Temperament of animals was subjectively evaluated using a 5-point scoring system at weighing, during which sheep spent 30 seconds on the scale. The heritability of temperament was low (0.10 ± 0.03). Estimated phenotypic ( r p ) and genetic ( r g ) correlations between temperament and litter size in ewes were negative and negligible ( P > 0.05) at −0.06 ± 0.18 and −0.08 ± 0.09, respectively. Significant genetic correlations were found between lamb temperament and preweaning growth rate ( r g = −0.44 ± 0.07, P ≤ 0.05) and postweaning growth till the age of 120 days ( r g = −0.52 ± 0.08, P ≤ 0.05). Significant genetic correlations were found between lamb temperament and growth rates during their first 3 months of age. As a result, selection for calm temperaments should translate to increased growth rates of lambs. Negative correlations between temperament and production traits, both in ewes and lambs, suggested that selection against animals that are highly reactive to improve welfare and ease of handling would not have detrimental impacts on productivity.

Diferenciação de populações ovinas encontradas no estado do Piauí

Objetivou-se analisar a semelhança fenotípica entre genótipos de ovinos localizados em oito microrregiões do Estado do Piauí, para averiguação da semelhança de caracteres morfométricos de animais da raça Santa Inês com os de outras raças da região, utilizando-se de análise multivariada. Nos rebanhos amostrados foram encontrados animais das raças Santa Inês, Dorper e Morada Nova, presente uma ou mais raça simultaneamente. As características morfológicas avaliadas foram tipo de pelagem e perfil do chanfro, já as métricas foram a altura de cernelha, a altura de garupa, a circunferência torácica, o comprimento corporal e o comprimento de orelha. Essas características foram avaliadas com as raças estratificadas por microrregião e, através da análise de componentes principais e de agrupamento de Ward, analisou-se a semelhança fenotípica entre as raças e também a variação dentro da raça Santa Inês, com base na relação entre as características medidas. Constatou-se que a raça Santa Inês apresentou variação no tamanho de acordo com a microrregião e que se apresenta com maior altura, mas com menor comprimento e perímetro corporal que a Dorper no Piauí. Já a Morada Nova foi a menor em tamanho. A raça Santa Inês apresentou um grupo de animal com maior tamanho corporal, localizado nas microrregiões de Floriano, Médio Parnaíba Piauiense, Campo Maior e Teresina. Outro grupo de tamanho intermediário, porém com comprimento corporal e circunferência torácica maior e orelha pequena, localizado na microrregião de São Raimundo Nonato, e um terceiro grupo, com tamanho intermediário, orelhas grandes e animais menores, localiza-se nas microrregiões do Litoral Piauiense e Valença. Pela análise de correspondência das características morfológicas com tipo de chanfro e o tipo de pelagem, foi possível identificar que os animais da raça Dorper no Estado apresentam alta correspondência com a característica lanada, que pode ser considerado uma desvantagem por estar numa região que prevalece alta temperatura ao durante o ano.

Reproduction Efficiency and Health Traits in Dorper, White Dorper, and Tsigai Sheep Breeds under Temperate European Conditions.

The objective of the current pilot study was to evaluate the reproductive performance and health indicators in Dorper, White Dorper, and Tsigai breed ewes managed semi-intensively under European temperate conditions. A total of 544 ewe-year units were observed, with ewes (ranging from 1.5 to 8 years of age) managed under identical rearing conditions for a period of two consecutive production cycles (2012 through 2013 and 2013 through 2014). In general, significant (p≤0.001) genotype-related disparities were found in occurrence rates for all health parameters taken into study. Clinical mastitis incidence was significantly lower (p≤0.05) in Dorper (9.4%) and White Dorper (10.8%) breeds compared to that of Tsigai ewes (17.4%). Significant differences (p≤0.05) for lameness were found between Dorper and Tsigai breeds, with occurrence rates of 8.0% and 2.9%, respectively. Incidence for pneumonia and abortion was not influenced (p>0.05) by the ewes’ genotype. Litter size was significantly lower (p≤0.05) in White Dorper breed than for Dorper and Tsigai ewes, of 1.21, 1.40, and 1.45, respectively. Conception rates and lambs survival were not affected (p>0.05) by genotype. Results suggest that South African Dorper and White Dorper sheep breeds have adapted well to the specific rearing conditions.

Selective brain cooling reduces water turnover in dehydrated sheep.

In artiodactyls, arterial blood destined for the brain can be cooled through counter-current heat exchange within the cavernous sinus via a process called selective brain cooling. We test the hypothesis that selective brain cooling, which results in lowered hypothalamic temperature, contributes to water conservation in sheep. Nine Dorper sheep, instrumented to provide measurements of carotid blood and brain temperature, were dosed with deuterium oxide (D2O), exposed to heat for 8 days (40◦C for 6-h per day) and deprived of water for the last five days (days 3 to 8). Plasma osmolality increased and the body water fraction decreased over the five days of water deprivation, with the sheep losing 16.7% of their body mass. Following water deprivation, both the mean 24h carotid blood temperature and the mean 24h brain temperature increased, but carotid blood temperature increased more than did brain temperature resulting in increased selective brain cooling. There was considerable inter-individual variation in the degree to which individual sheep used selective brain cooling. In general, sheep spent more time using selective brain cooling, and it was of greater magnitude, when dehydrated compared to when they were euhydrated. We found a significant positive correlation between selective brain cooling magnitude and osmolality (an index of hydration state). Both the magnitude of selective brain cooling and the proportion of time that sheep spent selective brain cooling were negatively correlated with water turnover. Sheep that used selective brain cooling more frequently, and with greater magnitude, lost less water than did conspecifics using selective brain cooling less efficiently. Our results show that a 50kg sheep can save 2.6L of water per day (~60% of daily water intake) when it employs selective brain cooling for 50% of the day during heat exposure. We conclude that selective brain cooling has a water conservation function in artiodactyls.

On-farm reproductive performance and adaptability evaluation of Dorper sheep crosses (DorperXAdilo) in different husbandry system, southern Ethiopia

A flock monitoring study was conducted in Wolaita zone, Damot gale and Damote sore districts and Siltie zone, Mirab Azernet district with the objectives of evaluating the reproductive and productive performance of Dorper sheep and to determine the current production systems. Data was collected from November 2013 to April according to Kaufmann case histories format and were subjected to general linear models (GLM) procedure of SAS. The fixed factors considered were breed, districts, season, birth type and lambing year. Mean birth weight, weaning weight, weaning age, market age, market weight, litter size, age at first lambing and sexual maturity for Dorper sheep were 2.25±1.72 kg, 17.30±0.98 kg, 3.16±0.55 months, 12.66±1.39 months, 30.66±3.26 kg, 1.48±0.71, 11.81±1.37 months and 5±0.74 months, respectively. Location, season, birth type, parity, sex and blood group had significantly (P<0.05) affected weaning weight. Season had influence on weaning age. Pre-weaning mortality rate of Dorper sheep was 2.93% and lower in Wolaita than Siltie zone. In Siltie, rather than Wolaita zone Dorper sheep was housing in the separate house. Housing Dorper sheep in separate house was good practice, so sharing the practice for the others through training, experience share and field trip should be needed. Further study is needed to characterize meat quality and carcass yield percentages from locally available feeds of Dorper sheep in the area. Key words: Adaptability, crosses, Dorper, husbandry, performance, Ethiopia.

Zoneamento bioclimático para a raça ovina Dorper no Estado de Pernambuco

O objetivo deste trabalho foi realizar o zoneamento bioclimático para ovinos da raça Dorper, no Estado de Pernambuco. Foram utilizados dados meteorológicos médios diários de 246 postos meteorológicos no estado. As variáveis temperatura do ar e umidade relativa do ar foram utilizadas para o cálculo do índice de temperatura e umidade. Com os valores destas variáveis, traçaram-se as isolinhas por meio do programa Surfer. A região do Agreste pernambucano apresenta melhores condições climáticas para a raça Dorper, durante todo o ano, do que a região que compreende o litoral, a Zona da Mata e o Semiárido. Nos meses mais quentes e nas regiões mais críticas, como o Sertão, é necessária a implementação de manejo, como o provimento de sombra, para amenizar o estresse pelo calor e não comprometer o desempenho produtivo da raça.

Estimations of genomic linkage disequilibrium and effective population sizes in three sheep populations

As one of the most important measures in population genetics, linkage disequilibrium (LD) is the basis of effective population size estimation, genomic selection, genome-wide association study and quantitative trait locus mapping. Here, we characterized the pattern of LD in three sheep populations (Sunite, German Mutton Merino, and Dorper) and subsequently estimated persistence of phase among them using the Illumina Ovine SNP50k Chip. In addition, we calculated the corresponding effective population sizes using the metric r2 estimated. The results showed that the extent of LD was highest in Dorpers, followed by German Mutton Merinos and Sunites. Average r2 values were 0.13, 0.20, and 0.22 at adjacent marker distances of 57.28, 59.01, and 59.93kb for Sunite, German Mutton Merino, and Dorper sheep, respectively. The average r2 values at the same genomic distance in German Mutton Merino and Dorper sheep were similar and higher than that in Sunite sheep, and the rate of LD decay over distance was faster than the rates in the other two sheep breeds. The correlation of phase for different breed comparisons ranged from 0.784 to 0.825. The effective population sizes in Sunite, German Mutton Merino, and Dorper sheep 7 generations ago were approximately 207, 74, and 67, respectively. We also detected a bottleneck in the effective population size for Sunite sheep that was consistent with the timing for the origin of the domestication of Chinese sheep. Our findings provide a theoretical reference for future genome marker-assisted evaluation and selection in sheep.

In silico identification and three-dimensional modelling of the missense mutation in ADAMTS2 in a sheep flock with dermatosparaxis.

Dermatosparaxis (Ehlers-Danlos syndrome in humans) is characterized by extreme fragility of the skin. It is due to the lack of mature collagen caused by a failure in the enzymatic processing of procollagenI. We investigated the condition in a commercial sheep flock. Mutations in the ADAM metallopeptidase with thrombospondin type 1 motif, 2 (ADAMTS2) locus, are involved in the development of dermatosparaxis in humans, cattle and the dorper sheep breed; consequently, this locus was investigated in the flock. A single affected lamb, its dam, the dam of a second affected lamb and the rams in the flock were studied. DNA was purified from blood, PCR primers were used to detect parts of the ADAMS2 gene and nucleotide sequencing was performed using Sanger's procedure. Skin samples were examined using standard histology procedures. A missense mutation was identified in the catalytic domain of ADAMTS2. The mutation is predicted to cause the substitution in the mature ADAMTS2 of a valine molecule by a methionine molecule (V15M) affecting the catalytic domain of the enzyme. Both the 'sorting intolerant from tolerant' (SIFT) and the PolyPhen-2 methodologies predicted a damaging effect for the mutation. Three-dimensional modelling suggested that this mutation may alter the stability of the protein folding or distort the structure, causing the protein to malfunction. Detection of the mutation responsible for the pathology allowed us to remove the heterozygote ram, thus preventing additional cases in the flock.

Aspectos clínicos, histopatológicos e moleculares da dermatosparaxia em ovinos White Dorper

Dermatosparaxia em animais é uma doença autossômica recessiva do tecido conjuntivo caracterizada por fragilidade e hiperextensibilidade cutânea. A doença em ovinos White Dorper é provocada pela mutação c.421G&gt;T no gene ADAMmetalopeptidase com trombospondina tipo 1 motif, 2 (ADAMTS2). O objetivo deste estudo foi descrever os achados clínicos, moleculares e histopatológicos da dermatosparaxia em ovinos White Dorper de um rebanho localizado no Centro-Oeste Paulista. O rebanho era composto por nove animais, sendo um reprodutor, quatro matrizes e seus respectivos borregos. Dos nove animais examinados, dois apresentavam sinais clínicos compatíveis com dermatosparaxia. O exame histopatológico de amostras cutâneas das lesões destes dois animais revelou também achados compatíveis com dermatosparaxia, sendo caracterizados por epiderme e anexos cutâneos preservados e sem características atípicas; colágeno displásico arranjado em feixes pequenos, fragmentados e com focos de degeneração, anexos cutâneos proeminentes e na região da derme foco hemorrágico intenso associado a moderado infiltrado neutrofílico na derme profunda. Com o objetivo de realizar o diagnóstico molecular da enfermidade, uma PCR foi padronizada utilizando primers específicos desenhados para amplificar a região do gene ADAMTS2 que continha a mutação c.421G&gt;T e o DNA obtido de amostras de sangue de todos os animais do rebanho. O sequenciamento direto dos produtos da PCR, comprovou que os dois animais clinicamente afetados possuíam a mutação responsável pela dermatosparaxia. A metodologia descrita neste estudo possibilitou o diagnóstico definitivo da doença. Segundo a literatura consultada, esta é a primeira vez que a dermatosparaxia é descrita em ovinos White Dorper no Brasil. A metodologia aqui descrita poderá ser empregada em estudos futuros que avaliem a prevalência desta mutação no Brasil, possibilitando a adoção de medidas que previnam a disseminação dessa mutação no rebanho brasileiro de ovinos White Dorper.

COMPORTAMIENTO REPRODUCTIVO DE OVEJAS DORPER Y KATAHDIN EMPADRADAS EN PRIMAVERA EN EL NORTE DE MÉXICO

&lt;p&gt;This study compared the ability of breeds Dorper and Katahdin to reproduce out of season. The ewes were kept in confinement conditions and fed with a whole diet (23.4% DM, 12.7% of CP and 2.3 Mcal ME). The sheep were exposed to males of their respective breeds in March-April (217 Dorper and 72 Katahdin) and in May-June (103 Dorper and 37 Katahdin). The proportion of ewe lambed was higher (P &amp;lt; 0.0001) in two breeds bred in March-April (67.7 and 72.2%) than May-June (38.8 and 29.7%), but prolificacy was similar (P &amp;gt; 0.05) in both breeds in the two breeding periods (1.35, 1.35, 1.15 and 1.36 lambs born/ewe lambed in the March-April and May-June breeding, in the Dorper and Katahdin breeds, respectively). It is concluded that ewes of hair Dorper and Katahdin sheep are able to reproduce outside of the reproductive season. However, reproductive efficiency was increased in ewes bred at the beginning than those bred at the end of spring season.&lt;/p&gt;

Energy requirements of Dorper crossbred ewe lambs1

The ME and NE requirements of Dorper crossbred ewe lambs grown from 35 to 50 kg BW were assessed in a comparative slaughter trial. Thirty-five ewe lambs (33.5 ± 0.6 kg BW) of F1 crosses of purebred Dorper and thin-tailed Han sheep were used: 7 lambs were slaughtered at the start of the trial to provide baseline measures of body composition and 7 lambs were fed ad libitum and slaughtered when they reached 43 kg BW to provide intermediate measures of body composition. The remaining 21 lambs were divided into 3 groups of 7 lambs each and fed a pelleted mixed diet (concentrate:roughage = 44:56, DM basis) for ad libitum intake or 65 or 45% of ad libitum intake. All 3 groups were slaughtered when the ad libitum group reached 50 kg BW. Total body energy, N, fat, ash, and moisture content were measured. In a separate trial, 15 ewe lambs (39.5 ± 0.7 kg BW) of F1 crosses of purebred Dorper and thin-tailed Han sheep were housed in metabolism cages to evaluate the ME value of the diet at each of the 3 levels of feed intake. In vivo methane production was measured by open-circuit respirometry along with the collection of all feces and urine. The daily NEm requirement of the ewe lambs was 280 kJ/kg metabolic BW (BW(0.75)) or 292 kJ/kg metabolic shrunk BW (SBW(0.75)), whereas the daily ME requirement for maintenance was 418 kJ/kg BW(0.75) or 437 kJ/kg SBW(0.75), with a partial efficiency of ME utilization for maintenance of 0.67. The NEg requirement ranged from 1.37 to 3.94 MJ/d for ADG from 100 to 250 g BW, and the partial efficiency of ME utilization for gain was 0.44. The NE and ME requirements of Dorper × thin-tailed Han crossbred ewe lambs were lower than the recommendations of the United States' nutritional system.

Analysis of Differential Gene Expression and Novel Transcript Units of Ovine Muscle Transcriptomes

In this study, we characterized differentially expressed genes (DEGs) between the muscle transcriptomes of Small-tailed Han sheep and Dorper sheep and predicted novel transcript units using high-throughput RNA sequencing technology. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that 1,300 DEGs were involved in cellular processes, metabolic pathways, and the actin cytoskeleton pathway. Importantly, we identified 34 DEGs related to muscle cell development and differentiation. Additionally, we were able to optimize the gene structure and predict the untranslated regions (UTRs) for some of the DEGs. Among the 123,678 novel predicted transcript units (TUs), 15,015 units were predicted protein sequences. The reliability of the sequencing data was verified through qRT-PCR analysis of 12 genes. These results will provide useful information for functional genetic research in the future.

Feed intake, digestibility, weight gain, and slaughter characteristics influenced by genetic percentage of Boer in goats and Dorper in sheep in the central highlands of Ethiopia

The objective of this experiment was to compare the feed intake, digestibility, growth performance, and slaughter characteristics of local genotypes of small ruminants in the central highlands of Ethiopia with Boer goat (B) and Dorper sheep (D) blood levels of 0%, 25%, and 50%. Male goats (27; 6-9 months of age) and sheep (27; 3-5 months) were housed individually in confinement during 90-day experiments. Grass hay (6% crude protein and 64% or 67% neutral detergent fiber) was consumed ad libitum together with concentrate (46% noug seed cake, 28% wheat bran, 24% sorghum grain, and 2% salt) supplemented at 2 % of their body weight. Initial body weight was 18.1, 20.8, and 24.9 kg for Local, 25% B, and 50% B, respectively, and 14.8, 20.3, and 17.9 kg for Local, 25% D, and 50% D, respectively. Total dry matter (DM) intake by goats ranked Local < 25% B < 50% B, and hay intake was greatest for 50% B. Intake of hay and total DM by sheep ranked Local < 50% D < 25% D. Average daily gain by goats was greatest for 50% B and by sheep was least for Local. Empty body weight of goats at slaughter and carcass weights ranked Local < 25% B < 50% B. Body and carcass weights of sheep were lowest for Local. In addition to the difference between 25% B and Local goats, these results clearly show potential for greater meat yield with the 50% than 25% level of B. The findings also depict considerable opportunity to increase meat production by crossbreeding with D, although greater benefit was not realized with 50% than 25% D.

The ecological adaptability of cloned sheep to free-grazing in the Tengger Desert of Inner Mongolia, China

Since the birth of the first cloned sheep, somatic cell nuclear transfer technology has been success- fully used to clone a variety of mammals. Cloned livestock have no apparent health risks, and the quality and safety of the cloned animal products are similar to non-cloned animals. The social behavior and environmental adapt- ability of postnatal cloned animals, especially when used for grassland farm production purposes, is unknown. In the present study, the cloned Dorper sheep equipped with GPS location devices were free-grazed in a harsh natural environment similar to conditions commonly experienced by Mongolian sheep. The main findings of this research were as follows. (1) Under free-grazing conditions, the cloned sheep showed excellent climatic and ecological adaptability. In extreme temperature conditions ranging from -30 to 40°C, the cloned sheep maintained acceptable body condition and behaved as other sheep. (2) The cloned sheep quickly adapted from a herd feeding strategy to the harsh environment and quickly exhibited a grazing regi- men as other free-grazing sheep. (3) The cloned sheep exhibited free-grazing patterns and social behavior as other sheep. (4) The cloned sheep in the harsh environment thrived and produced healthy lambs. Overall, the cloned Dorper sheep exhibited excellent ecological adaptation, which is an important consideration for breeding meat sheep by cloning. The Dorper sheep readily adapted to the free-grazing conditions on the Mongolian plateau grass- land, which attests to their ability to withstand harsh environmental conditions.

Effects of different dietary intake on mRNA levels of MSTN, IGF-I, and IGF-II in the skeletal muscle of Dorper and Hu sheep hybrid F1 rams.

MSTN, IGF-І(insulin-like growth factor-І) and IGF-II (insulin-like growth factor-II) regulate skeletal muscle growth. This study investigated the effects of different dietary intake levels on skeletal muscles. Sheep was randomly assigned to 3 feeding groups: 1) the maintenance diet (M), 2) 1.4 x the maintenance diet (1.4M), and 3) 2.15 x the maintenance diet (2.15M). Before slaughtering the animals, blood samples were collected to measure plasma urea, growth hormone, and insulin concentrations. After slaughtering, the longissimus dorsi, semitendinosus, semimembranosus, gastrocnemius, soleus, and chest muscle were removed to record various parameters, including the mRNA expression levels of MSTN and IGFs, in addition to skeletal muscle fiber diameter and cross-sectional area. The result showed that as dietary intake improved, the mRNA expression levels of MSTN and IGF-II decreased, whereas IGF-Іexpression increased. The mRNA expression levels of MSTN and IGFs were significantly different in the same skeletal muscle under different dietary intake. The skeletal muscle fiber diameter and cross-sectional area increased with greater dietary intake, as observed for the mRNA expression of IGF-І; however, it contrasted to that observed for the mRNA expression of MSTN and IGF-II. In conclusion, dietary intake levels have a certain influence on MSTN and IGFs mRNA expression levels, in addition to skeletal muscle fiber diameter and cross-sectional area. This study contributes valuable information for enhancing the molecular-based breeding of sheep.

Introduction of Dorper sheep into Australian rangelands: implications for production and natural resource management

The growing popularity of the Dorper breed of sheep potentially may have implications for the ecological sustainability of the semiarid and arid rangelands of southern Australia. The implications are heightened by forecasts of a warming and drying climate in these rangelands, which may in itself place native vegetation under increasing stress. While the Dorper breed of sheep offers important production advantages, little is known from research under Australian conditions about their grazing ecology and management requirements from a natural resource perspective. Key factors identified from this review of literature from other countries include a high fertility and fecundity, a generalist feeding strategy, a high growth rate and a capacity to survive and reproduce under low-rainfall conditions. The wider range of plant species selected by the Dorper compared with the traditional Merino breed of sheep potentially creates both opportunities and risks for rangeland condition. Less selective grazing may reduce pressure on some species but the capacity to harvest sufficient nutrients over a smaller area could concentrate grazing and promote resource degradation. High reproductive efficiency under a wide range of seasonal conditions may lead to more rapid onset of overgrazing and will require close attention to both natural resources and animal marketing if resource degradation is to be avoided.

The Effects of Pre-slaughter Stress and Season on the Activity of Plasma Creatine Kinase and Mutton Quality from Different Sheep Breeds Slaughtered at a Smallholder Abattoir.

The objective of the current study was to determine the effect of pre-slaughter stress, season and breed on the activity of plasma creatine kinase (CK) and the quality of mutton. One hundred and seventy-three (173) castrated sheep from Dormer (DM), South African Mutton Merino (SAMM), Dorper (DP) and Blackhead Persian (BP) sheep breeds were used in the study. The animals were grouped according to age-groups as follows: Group 1 (6 to 8 months), Group 2 (9 to 12 months) and Group 3 (13 to 16 months). Blood samples were collected during exsanguinations using disposable vacutainer tubes for CK analysis. Representative samples of the Muscularis longissimuss thoracis et. lumborum (LTL) were collected from 84 castrated sheep, of different breeds (28 per breed) 24 h after slaughter. The following physico-chemical characteristics of mutton were determined; meat pH (pH24), color (L*, a* and b*), thawing and cooking losses and Warner Braztler Shear Force (WBSF). The activity of plasma CK was significantly higher (p<0.001) in summer (1,026.3±105.06) and lower in winter (723.3±77.75). There were higher values for L* (33.7±0.94), b* (11.5±0.48) and WBSF (29.5±1.46) in summer season than in winter season; L* (29.4±0.64), b* (10.2±0.33) and WBSF (21.2±0.99). The activity of plasma CK was influenced by the type of breed with Dormer having the highest (p>0.001) levels (1,358.6±191.08) of CK. South African Mutton Merino had higher values for pH24 (5.9±0.06), L* (34.2±0.97), b* (12.2±0.50) and WBSF (26.8±1.51) and Blackhead Persian had higher values (35.5±2.17) for cooking loss (CL%) than the other breeds. Computed Principal Component Analyses (PCA) on the activity of plasma CK and physico-chemical characteristics of mutton revealed no correlations between these variables. However, positive correlations were observed between pH24, L*, a*, b*, CL% and WBSF. Relationships between pre-slaughter stress, CK activity and physico-chemical characteristics of mutton were also observed. It was therefore concluded that although mutton quality and creatine kinase were not related, pre-slaughter stress, season and breed affected the activity of creatine kinase and mutton quality.

Characterization and Comparative Analyses of Muscle Transcriptomes in Dorper and Small-Tailed Han Sheep Using RNA-Seq Technique

The sheep is an important domestic animal and model for many types of medically relevant research. An investigation of gene expression in ovine muscle would significantly advance our understanding of muscle growth. RNA-seq is a recently developed analytical approach for transcriptome profiling via high-throughput sequencing. Although RNA-seq has been recently applied to a wide variety of organisms, few RNA-seq studies have been conducted in livestock, particularly in sheep. In this study, two cDNA libraries were constructed from the biceps brachii of one Small-tailed Han sheep (SH) and one Dorper sheep (DP). The Illumina high-throughput sequencing technique and bioinformatics were used to determine transcript abundances and characteristics. For the SH and DP libraries, we obtained a total of 50,264,608 and 52,794,216 high quality reads, respectively. Approximately two-thirds of the reads could be mapped to the sheep genome. In addition, 40,481 and 38,851 potential coding single nucleotide polymorphisms (cSNPs) were observed, respectively, of which a total of 59,139 cSNP coordinates were different between the two samples. Up to 5,116 and 5,265 respective reference genes had undergone 13,827 and 15,684 alternative splicing events. A total of 6,989 reference genes were extended at the 5’, 3’ or both ends, and 123,678 novel transcript units were found. A total of 1,300 significantly differentially expressed genes were identified between the two libraries. These results suggest that there are many differences in the muscle transcriptomes between these two animals. This study addresses a preliminary analysis and offers a foundation for future genomic research in the sheep.

Estudo anatomorfológico, radiográfico e tomográfico de Schistosomus reflexus em ovino da raça Dorper: relato de caso

O Schistosomus reflexus (SR) é uma anomalia congênita fatal e rara, primariamente observada em ruminantes, a qual apresenta feto com dorsoflexão da coluna vertebral, exposição das vísceras abdominais e torácicas e escoliose. Foi realizada uma cesariana de ovelha da raça Dorper, em propriedade da região de Botucatu-SP. Pelas características gerais e achados de necropsia, tratava-se de um caso de SR. A radiografia revelou acentuado desvio ventrodorsal do segmento da coluna vertebral toracolombar e deformidades das costelas. Na tomografia computadorizada, observou-se presença da integridade dos ossos e órgãos, exceto ausência de uma vértebra lombar. Não havia dados na literatura de diagnóstico por imagem de SR em ovinos, portanto procedeu-se, de forma inédita, a exames radiográfico e tomográfico do feto.