Wool traits of three sympatric sheep populations in Chiapas Region, México

A total of 344 pure animals, representing seven American and South European breeds (White Chiapas Blanca, Brown Chiapas Café, Black Chiapas Negra, Churra Badana, Churra da Terra Quente, Chilean Latxa, and Spanish Merino), were randomly sampled and wool evaluated for isoalcohol scouring yield, length, and proportion for each type of fiber (long-thick, short-thin, and kemp), average of fiber diameter, and F30 (percentage of fibers with a diameter of >30 μm). The objective of this study was to characterize these breeds according to their wool traits. A low percentage of the phenotypic variability in the analyzed animals was due to differences among breeds, and that the largest part of that variability is due to differences within breeds. The obtained topology in the principal coordinates analysis showed the grouping of the three Chiapas breeds clearly separated, but the similarity with their original breed was only evident for Brown Chiapas Café. The three Chiapas sheep breeds must be regarded as clearly sympatric populations.     

Genetic characterisation of Burkina Faso goats using microsatellite polymorphism

A total of 133 reproductive individuals belonging to the 3 Burkina Faso goat breeds (Djallonké, Mossi and Sahelian) were analysed for 27 microsatellites. Additionally, 72 blood samples belonging to two reproductively isolated subpopulations of the endangered Spanish Bermeya goat were used as outgroup. The between-Burkinabé goat breeds molecular coancestry varied from 0.418 ± 0.006 (Mossi–Sahelian) to 0.450 ± 0.007 (Djallonké–Mossi) and exceeded that computed between the Bermeya subpopulations (0.372 ± 0.006). Moreover, the computed between-Burkinabé F_ST's varied from 0.023 ± 0.003 (Djallonké–Mossi) to 0.038 ± 0.004 (Djallonké–Sahelian). Structure and degree of admixture of the Burkinabé goat population were assessed using the program STRUCTURE and showed a significant introgression of the Sahelian goat southwards. The classification of the Burkinabé goat into different breeds did not have strong genetic support at the microsatellite level due to the rough definition of livestock breeds in Africa, historical gene flow patterns and desertization. The Mossi goat can be considered a transition breed between the two major Burkinabé goat populations (Djallonké and Sahelian).     

The biodiversity and genetic structure of Balearic sheep breeds

The Balearic sheep breeds, Mallorquina, Menorquina, Roja Mallorquina, Ibicenca and one possible new genetic group, Formentera, constitute a unique genetic resource in the Mediterranean farming landscape, displaying high genetic diversity levels and being well differentiated among themselves and with respect to the continental sheep breeds. We used a microsatellite panel of markers to study genetic diversity and relationships with other Spanish breeds. The results reported in this study have important implications for the use, conservation and breeding of Balearic sheep stocks. A mean number of 7.59 alleles was found among the Balearic sheep breeds for the microsatellites scored. The whole mean value of observed heterozygosity amounted to 0.62, whereas the expected heterozygosity value was 0.69, suggesting the presence of a great degree of genetic variability, although a significant deficit of heterozygotes was detected for some markers. Genetic distance estimates showed that Balearic sheep are differentiated from the other Spanish breeds and in particular, from the Merino type. The Ibicenca breed showed the highest distance value from other breeds. The neighbour‐net method of analysis clustered the Roja Mallorquina, Menorquina and Mallorquina breeds. The Structure results clearly demonstrated the genetic differentiation among the four Balearic sheep breeds, with the Ibicenca and Formentera races joined, with slight migration among them. Few external genetic influences from the Spanish mainland breeds were detected.     

中国地方绵羊群体TYRP1基因遗传变异研究

本研究旨在了解酪氨酸酶相关蛋白1（tyrosinase related protein 1，TYRP1）基因在中国地方绵羊群体内的遗传变异，以及TYRP1基因突变与不同毛色表型绵羊群体的相关性。通过直接测序法和PCR-RFLP技术对10个中国地方绵羊群体进行单核苷酸多态性（SNP）检测，利用Beagle、PLINK和POPGENE等软件对突变位点数据进行单倍型构建、连锁不平衡分析和遗传变异研究。突变位点检测结果表明，在绵羊TYRP1基因内识别了13个SNPs，其中位于TYRP1基因外显子上的10个SNPs位点，除个别位点在大尾寒羊、中国美利奴羊和岷县黑裘皮羊中没有发生突变外，其他突变位点在所有绵羊品种中均出现不同程度变异，说明中国地方绵羊群体具有较高的遗传多样性。单倍型分析结果表明，所有样本中共有42个单倍型，优势单倍型0000000000（245/918）、0100000001（91/918）在所有绵羊群体中均存在，除单倍型0101100000（93/918）在中国美利奴羊中没有出现，单倍型0001000001（69/918）在岷县黑裘皮羊、哈萨克羊群体中没有出现外，在其他群体中均存在。连锁分析结果表明，10个SNPs在所有样本中均存在2个连锁模块。群体遗传变异分析表明，中国地方绵羊群体具有较高水平的群体内遗传变异，各绵羊品种间存在明显的遗传分化模式，且各品种遗传关系与其品种传统分类结果基本一致。本研究为进一步研究TYRP1基因对绵羊毛色遗传性状的影响提供了参考依据。     

甘肃地方绵羊品种微卫星遗传多样性与系统发育分析

通过对甘肃省6个地方绵羊品种(240只个体)15个微卫星座位的等位基因的研究,结果共发现了179个等位基因。其中在藏羊中发现的等位基因数最多(136个),兰州大尾羊最少(94个)。多态信息含量、期望杂合度和观察杂合度的数据表明:在研究的6个绵羊品种中藏羊和甘肃高山细毛羊的遗传多样性较丰富,而兰州大尾羊和岷县黑裘皮羊的遗传多样性较低。DA遗传距离和D s遗传距离构建的NJ系统发育树均表明:兰州大尾羊、蒙古羊和滩羊具有较近的亲缘关系,预示这3个品种可能具有相同的原始祖先。而甘肃高山细毛羊与其他5个甘肃地方品种的遗传距离较远,另为一类。     

Romilly Hills羊遗传多样性的微卫星分析

利用 1 0个微卫星标记对新疆兵团农七师从南非引进的罗米丽 (RomillyHills)绵羊和中国美利奴羊 (新疆军垦型 )遗传多样性进行了检测。统计了两群体的等位基因组成、平均有效等位基因数 (E)和平均基因纯合率 ,利用等位基因频率计算出两群体的平均遗传杂合度 (h)、多态信息含量 (PIC)。结果表明 1 0个微卫星位点在RomillyHills羊、中国美利奴羊群体中的平均多态信息含量分别为 0 5952和 0 5859,除BM1 82 4、MAF65外均为高度多态 ,可作为有效的遗传标记用于两品种绵羊遗传多样性分析 ;RomillyHills羊的群体遗传变异大于中国美利奴羊 ,其遗传多样性相对丰富 ,有较大的选育潜力。     

Allele distributions of two novel SNPs within the sheep Cyp19 gene

Oestrogen is an important regulator of reproduction and growth. The key enzyme of oestrogen biosynthesis, aromatase cytochrome P450, is encoded by the Cyp19 gene. In order to generate genetic markers for the sheep Cyp19 gene, two novel single nucleotide polymorphisms (SNPs), one located in promoter 2 (P2), the other one in intron 9 (I9), were identified by a comparative sequencing approach. The allele distributions of both SNPs were investigated by means of Polymerase chain reaction‐restriction fragment length polymorphism analysis (PCR‐RFLP) in five economically relevant sheep breeds (British Milk Sheep, Carranzana, Latxa Black Face, Latxa White Face, Merino) and three ancient Hungarian breeds kept as gene reserves (Cikta, Racka, Tsigai). In British Milk Sheep, only the intronic SNP was present whereas in Merino, Cikta, Racka, Tsigai, Carranzana, Latxa Black Face and Latxa White Face, both SNPs could be found. This indicates that the newly identified SNPs can be used as markers for the Cyp19 locus in various sheep breeds.     

SHH在美利奴羊与小尾寒羊背部皮肤表达差异的研究

为了研究音猬因子(sonic hedgehog, SHH)在不同品种绵羊背部皮肤中的表达差异,以探索SHH与羊毛弯曲形成的关系,选取美利奴羊和小尾寒羊作为研究对象,利用HE染色法观察2种绵羊背部皮肤的组织结构,采用免疫组织化学技术、实时荧光定量PCR和Western blot方法探究2种绵羊背部皮肤中SHH蛋白和基因水平的相对表达量差异。结果显示:HE染色显示美利奴羊与小尾寒羊背部皮肤毛囊的组织结构存在毛囊数量及弯曲程度等差异;免疫组织化学试验显示,SHH蛋白在美利奴羊和小尾寒羊背部皮肤中均有表达,在美利奴羊背部皮肤中的毛乳头、毛基质、内外根鞘、皮脂腺和表皮细胞中显著表达,在小尾寒羊背部皮肤中的毛基质、内外根鞘和皮脂腺中显著表达;光密度分析显示,美利奴羊背部皮肤组织中SHH蛋白的表达量显著高于小尾寒羊(P<0.001);实时荧光定量PCR显示,美利奴羊SHH mRNA相对表达水平显著高于小尾寒羊(P<0.01);Western blot显示,美利奴羊SHH蛋白相对表达水平显著高于小尾寒羊(P<0.01)。提示:羊毛弯曲的形成与其组织结构有关,并受SHH的调控。     

SHH在美利奴羊与小尾寒羊背部皮肤表达差异的研究

为了研究音猬因子(sonic hedgehog, SHH)在不同品种绵羊背部皮肤中的表达差异,以探索SHH与羊毛弯曲形成的关系,选取美利奴羊和小尾寒羊作为研究对象,利用HE染色法观察2种绵羊背部皮肤的组织结构,采用免疫组织化学技术、实时荧光定量PCR和Western blot方法探究2种绵羊背部皮肤中SHH蛋白和基因水平的相对表达量差异。结果显示:HE染色显示美利奴羊与小尾寒羊背部皮肤毛囊的组织结构存在毛囊数量及弯曲程度等差异;免疫组织化学试验显示,SHH蛋白在美利奴羊和小尾寒羊背部皮肤中均有表达,在美利奴羊背部皮肤中的毛乳头、毛基质、内外根鞘、皮脂腺和表皮细胞中显著表达,在小尾寒羊背部皮肤中的毛基质、内外根鞘和皮脂腺中显著表达;光密度分析显示,美利奴羊背部皮肤组织中SHH蛋白的表达量显著高于小尾寒羊(P<0.001);实时荧光定量PCR显示,美利奴羊SHH mRNA相对表达水平显著高于小尾寒羊(P<0.01);Western blot显示,美利奴羊SHH蛋白相对表达水平显著高于小尾寒羊(P<0.01)。提示:羊毛弯曲的形成与其组织结构有关,并受SHH的调控。     

6个绵羊群体BMP15、GDF9基因多态性分析

本研究旨在检测新吉细毛羊、中国美利奴羊（无角型）、东北细毛羊、杜×寒杂交羊（F1）、杜×寒杂交羊（F3）、白头杜泊羊6个绵羊群体骨形态发生蛋白15（bone morphogenetic protein 15,BMP15）、生长分化因子9（growth differentiation factor 9,GDF9）基因的多态性,为绵羊繁殖力的标记辅助选择和育种提供理论依据。以6个绵羊群体共378只个体为研究对象,利用PCR-SSCP技术检测BMP15、GDF9基因多态性;用DNAStar软件与I-TASSER软件预测蛋白质二级结构和三级结构;计算基因频率、基因型频率、Hardy-Weinberg平衡、杂合度（He）、纯合度（Ho）、有效等位基因数（Ne）和多态信息含量（PIC）。运用GraphPad Prism 6软件对新吉细毛羊群体BMP15基因多态性与产羔数进行相关性分析。结果显示,BMP15基因P1引物扩增片段存在多态性,6个群体共呈现3种基因型：AA、AC、CC,该突变为BMP15基因外显子1上58-60 bp 3个碱基（CTT）缺失,新吉细毛羊、杜×寒杂交羊（F3）、白头杜泊羊的χ²值均达到显著水平,处于Hardy-Weinberg不平衡状态,不同基因型间新吉细毛羊平均产羔数差异均不显著（P>0.05）;GDF9基因P2引物扩增片段存在多态性,6个群体共呈现3种基因型：DD、DE、EE,其中新吉细毛羊仅有1种基因型：DD,该突变为GDF9基因外显子2上477 bp处T→C的转换,该突变未导致氨基酸的改变,除新吉细毛羊外其余5个群体χ²值均未达到显著水平,处于Hardy-Weinberg平衡状态,说明GDF9基因T477C突变不能作为新吉细毛羊多胎性状遗传标记位点。     

4个肉用绵羊品种微卫星标记的多态性与系统发育分析

利用10个微卫星座位对4个肉用绵羊品种进行遗传检测,计算出了各品种的平均杂合度、平均多态信息含量及品种间的遗传距离,并进行了系统发育分析。结果表明:10个微卫星座位上共检测到了107个等位基因,等位基因数在5~13个之间。各基因座位多态信息含量为0.498 5~0.890 4,均表现出了高度多态性。各基因座位杂合度较高,为0.563 0~0.899 5,说明肉用绵羊品种有着较丰富的遗传多样性。4个肉用绵羊品种间的遗传距离相对较远,萨福克羊和陶赛特羊先聚在一起,他们之间的遗传距离最近,为0.345 25,然后与夏洛来羊聚在一起,最后与中国美利奴羊聚在一起,中国美利奴羊与夏洛来羊之间的遗传距离最远,为0.516 39。研究结果对我国肉用绵羊资源的评估、保存和预测杂种优势具有一定的指导意义。     

Study of the Genetic Origin of the Mexican Creole Donkey (Equus asinus) by Means of the Analysis of the D-Loop Region of Mitochondrial DNA

The aim of this work was to analyse the genetic origin of the Mexican Creole donkey, as well as its genetic diversity, by comparison with Spanish and African donkey populations by means of the D-loop region of mitochondrial DNA. To this end, the genomic DNA of 68 Mexican Creole donkeys from eight geographical regions in six States of the Republic of México and from a Sicilian donkey was obtained. By the polymerase chain-reaction technique (PCR) a fragment of 541 bp was amplified, corresponding to the most informative region of the mitochondrial DNA, the D-loop. The fragments were subsequently sequenced. The analysed sequences revealed 10 new Mexican haplotypes that were different from those of the Spanish and African breeds with which they were compared, showing high levels of genetic diversity. Analysis of the phylogenetic relationships in the different Creole varieties showed a tendency of origin towards Spanish breeds, mainly the Andaluza, Zamorano-Leonesa and Majorera from the Canary Islands; these in turn showed an African origin, seven Mexican haplotypes and three haplotypes similar to those analysed by Aranguren and colleagues (2004) of Spanish and African breeds being obtained. This work allows us to reach the preliminary conclusion that the origin of Mexican Creole donkey populations in the different states of the Republic of México is clearly of Iberian origin, the Spanish donkey breed Andaluza being the main one contributing to the populations of the Mexican Creole donkeys, followed by the Spanish breeds Zamorano-Leonesa and Majorera from the Canary Islands, and that the populations possess high levels of genetic diversity.     

Genetic diversity and population structure of the endangered Namaqua Afrikaner sheep

The Namaqua Afrikaner is an endangered sheep breed indigenous to South Africa, primarily used in smallholder farming systems. Genetic characterization is essential for the breed’s conservation and utilization. In this study, a genetic characterization was performed on 144 Namaqua Afrikaner sheep kept at the Karakul Experimental Station (KES), Carnarvon Experimental Station (CES), and a private farm Welgeluk (WGK) using 22 microsatellite markers. The mean number of alleles observed was low (3.7 for KES, 3.9 for CES, and 4.2 for WGK). Expected heterozygosity values across loci ranged between 46 % for WGK, 48 % for KES, and 55 % for CES, indicating low to moderate genetic variation. The analysis of molecular variance revealed that 89.5 % of the genetic variation was due to differences within populations. The population structure confirmed the differentiation of three clusters with high relationships between the CES and WGK populations. In the population structure comparison with Pedi and South African Mutton Merino sheep, limited hybridization between the Namaqua Afrikaner sheep and both of these breeds was observed. The results of this study will serve as a reference for genetic management and conservation of Namaqua Afrikaner sheep.     

Genetic diversity and matrilineal genetic origin of fat-rumped sheep in Ethiopia

Ethiopia is home to a diverse gene pool of indigenous sheep populations. Therefore, a better understanding of genetic variation holds the key to future utilization through conservation. Three of these breeds, Afar, Blackhead Somali, and Hararghe Highland, are found in eastern Ethiopia where they contribute significantly to the livelihood of most pastoralist, agro-pastoralist, and smallholder farmers. These indigenous sheep are recognized on the basis of morphotype and their genetic distinction remains unknown. Here, to assess genetic variation, and matrilineal genetic origin and relationship of fat-rumed sheep found in eastern Ethiopia, 300 individuals from the three breeds were genotyped for 22 microsatellite markers and sequenced for the mitochondrial DNA displacement loop (mtDNA d-loop) region. The overall H_O and H_E were 0.57 and 0.75, respectively. Differentiation statistics revealed that a high proportion (97%) of the total genetic variation was explained by differences between individuals within populations. Genotype assignment independent of the population of origin showed K?=?2 to be the optimum number of genetic backgrounds present in the dataset. This result was further confirmed by mtDNA D-loop sequences comparison in which the matrilineal genetic origin of eastern Ethiopia sheep is from two haplotype groups (types A and B) among the five haplotypes globally observed. Taken together, our findings suggest that the sheep populations from three breeds originated from two ancestral genetic backgrounds that may have diverged prior to their introduction to Ethiopia. However, to obtain a complete picture of the evolutionary dynamics of Ethiopian indigenous sheep, more samples and populations from within and outside of the country will need to be analyzed.

     

绵羊PRLR基因内含子9和外显子10多态性与产羔数的关系研究

本研究采用PCR-SSCP技术对绵羊催乳素受体（PRLR）基因内含子9和外显子10部分核苷酸多态性及其与小尾寒羊、中国美利奴（新疆型）绵羊多胎品系、肉用品系、体大品系、萨福克、无角陶赛特、中国美利奴（新疆型）和德国肉用美利奴产羔数间的关系进行了分析。结果发现：①在绵羊PRLR基因内含子9的第259 bp处,存在C→T转换,BB基因型的小尾寒羊平均产羔数分别较AA和AB基因型提高0.81和0.87只（P<0.05）;②在绵羊PRLR基因外显子10的第304 bp处存在一个G→A转换,该突变导致PRLR基因第387位氨基酸残基由Glu突变为Lys,并使中国美利奴（新疆型）多胎品系中AB基因型的平均产羔数较AA和BB基因型增加0.58和0.80只（P<0.05）;③在绵羊PRLR基因外显子10第571、585和606 bp处分别存在G→A、C→G和C→T突变;其中前2处突变分别导致PRLR基因的第476位氨基酸由Ala突变为Thr,第480位氨基酸由Ser突变为Arg。其中第571 bp处突变导致小尾寒羊AB基因型的平均窝产羔数显著高于AA基因型的窝产羔数,增加0.8 只（P<0.05）。以上结果提示,PRLR基因可能是控制小尾寒羊和中国美利奴（新疆型）绵羊多胎品系产羔数的主效基因或与之存在紧密的遗传连锁。     

Study of the genetic origin of the Mexican creole donkey (Equus asinus) by means of the analysis of the D-loop region of mitochondrial DNA

The aim of this work was to analyse the genetic origin of the Mexican Creole donkey, as well as its genetic diversity, by comparison with Spanish and African donkey populations by means of the D-loop region of mitochondrial DNA. To this end, the genomic DNA of 68 Mexican Creole donkeys from eight geographical regions in six States of the Republic of Mexico and from a Sicilian donkey was obtained. By the polymerase chain-reaction technique (PCR) a fragment of 541 bp was amplified, corresponding to the most informative region of the mitochondrial DNA, the D-loop. The fragments were subsequently sequenced. The analysed sequences revealed 10 new Mexican haplotypes that were different from those of the Spanish and African breeds with which they were compared, showing high levels of genetic diversity. Analysis of the phylogenetic relationships in the different Creole varieties showed a tendency of origin towards Spanish breeds, mainly the Andaluza, Zamorano-Leonesa and Majorera from the Canary Islands; these in turn showed an African origin, seven Mexican haplotypes and three haplotypes similar to those analysed by Aranguren and colleagues (2004) of Spanish and African breeds being obtained. This work allows us to reach the preliminary conclusion that the origin of Mexican Creole donkey populations in the different states of the Republic of Mexico is clearly of Iberian origin, the Spanish donkey breed Andaluza being the main one contributing to the populations of the Mexican Creole donkeys, followed by the Spanish breeds Zamorano-Leonesa and Majorera from the Canary Islands, and that the populations possess high levels of genetic diversity.     

Kinetics of NDV specific antibodies in chickens—V. Analysis of frequency distributions of antibody titers against Newcastle disease virus by investigation of random samples in chicken flocks

Chicks and chickens maintained under commercial conditions were vaccinated against Newcastle Disease via drinking water. Prior and after different times of vaccination blood samples were drawn from different numbers of birds and checked for HI antibodies. The modes of distribution of the antibody titers within the random sample were assayed. The following results were obtained:

1. 1. On the basis of the distribution of the serum titers can be concluded whether the antibody level within a flock is increasing or decreasing.

◦ —A right steep asymmetry can be observed up to 20 days post vaccination.

◦ —In the phase of maximal antibody levels an almost symmetric distribution of the titers is present.

◦ —In later times (more than three weeks p. vacc.) the distribution shows a left steep asymmetry (Poisson distribution).

2. 2. A poisson distribution is also observable during the elimination of maternal antibodies of chicks until complete elimination.

3. 3. The mode of distribution of the HI titers in sera of day-old chicks correlates with the mode of distribution of the dams. Therefore, conclusions are possible from the status of the chicks to the dams and reverse.

4. 4. Factors which interfere with the mode of distribution are:

◦ —Two or more peaks after vaccination of chickens. This indicates an uneven immune response within the flock.

◦ —Distributions with several peaks may also occur if flocks are composed of day-old chicks from parent flocks with different levels of antibody titers.

新疆4种绵羊羊毛氨基酸含量测定

为了研究遗传及环境对羊毛生产性状的影响,利用高效液相色谱法测定了新疆地区和田羊、卡拉库尔羊、多浪羊、中国美利奴羊4个绵羊品种羊毛中的17种氨基酸含量,探索不同品种绵羊间和同一品种不同品系绵羊间羊毛氨基酸含量的差异。结果表明,和田羊羊毛的氨基酸总含量显著高于多浪羊羊毛,差异显著(P＜0.05);其他品种间氨基酸总量差异不显著。多浪羊羊毛中的Asp、Ser、Glu、Arg、Thr、Ala、Pro、Val、Lys、Ile、Leu、Phe等氨基酸含量均低于其他品种;卡拉库尔羊羊毛只有Cys含量高于其他品种,Ser、Gly、Thr、Pro、Tyr等氨基酸含量均低于其他品种。各品种羊毛的螺旋比值(促螺旋氨基酸含量/阻螺旋氨基酸含量),中国美利奴为0.90,卡拉库尔羊为0.79,和田羊为0.77,多浪羊为0.75。结果表明,和田羊氨基酸总含量高于其他品种,中国美利奴螺旋比值高于其他品种,卡拉库尔羊Cys含量高于其他品种。     

Assessing carcass and meat characteristics of Damara, Dorper and Australian Merino lambs under restricted feeding

Seasonal weight loss (SWL) is the most pressing constraint in ruminant production systems in tropical climates. SWL is controlled using supplementation, which is costly and difficult to implement in extensive systems, or using breeds adapted to tropical hot dry climates, like the Damara and Dorper. Albeit 15 years in Australia, little is known on how these sheep compare to Australian Merino. Here, the responses of the Damara, Dorper and Merino breeds to nutritional stress were compared. Seventy-two 6-month-old ram lambs, 24 from each breed, were allocated to growth (gaining 100 g/day) or restricted diets (losing 100 g/day, 85 % of maintenance needs). Animals were weighed and carcass and meat characteristics determined. Results point out to the existence of important differences between the three genotypes, in particular between the Merino and the Southern African breeds. Additionally, Merino ram lambs seem to have been more influenced by SWL than the other two, with consequences on meat characteristics.     

Effects of the scab mite Psoroptes ovis on the haematology and live mass of Merino and Dorper sheep

Five Merino and five Dorper sheep were artificially infested with the sheep scab mite Psoroptes ovis and the effect of infestation on their haematology, serum protein levels and live mass recorded for a period of 14 weeks. The reaction of the Merino sheep to infestation was more severe than that of the Dorper sheep. Haematological values fluctuated within the normal range during the assessment period. The mean haemoglobin concentration of the Merino sheep declined until antiparastic treatment was administered 10 weeks after infestation, after which it gradually increased. The lymphocyte counts of both breeds of sheep declined from 2 weeks to 10 weeks post-infestation, but increased after treatment, while the highest eosinophil counts were recorded in the Merino sheep at the height of the acute disease 8-10 weeks post-infestation. Serum albumin values for both breeds and serum globulin values for the Merino sheep were higher than normal during the entire 14-week observation period. A decrease in serum albumin and an increase in serum globulin concentration occurred at the height of infestation in both breeds. The mean live mass of a second group of five infested Merino sheep decreased by 6.4 kg over a 16-week period compared to a gain of 4.56 kg for five infested Dorper sheep.