Detection of Novel Variations Related to Litter Size in BMP15 Gene of Luzhong Mutton Sheep (Ovis aries)

Litter size is an important economic trait in the mutton sheep industry. BMP15 is one of the key candidate genes for litter size in sheep. In this study, the entire ORF region of BMP15 was sequenced in 154 Luzhong mutton ewes, and the novel variations were determined. The association between polymorphism in BMP15 and litter size was analyzed using a general linear model. Six out of a total of thirteen variations were identified to be novel. Association analysis indicated that four (SNPs ENSOART00000010201.1:c.352+342C>A, c.352+1232T>C, c.352+1165A>G and c.353-2036T>A) were significantly associated with litter size. The joint analysis among three major genes (BMP15, BMPR1B and GDF9) exhibited significant interaction effects in three combinations (FecB and c.352+1232T>C of BMP15; FecB and c.352+1165A>G of BMP15; c.352+342C>A of BMP15 and ENSOART00000014382.1:c.994G>A of GDF9). For the SNPs c.352+1232T>C and c.352+342C>A, the global distribution of allele frequencies showed that the highest variation frequency occurs in Western Europe. In conclusion, the results demonstrated that BMP15 is a major gene for litter size in Luzhong mutton sheep and candidate SNPs associated with litter size were identified.

A Meta-analysis Study of Association Between FecB Polymorphism and Litter Size in Sheep

Litter size is perhaps the main commercial trait since it has an observable effect on benefit in the sheep industry. Fecundity genes, play a vital role in expression of litter size. One of the most popular of these genes is the Booroola gene (FecB). In many past researches there was a dependency between the BMPR1B gene polymorphism and litter size of sheep. In the current study, a meta-analysis directed by coalescing outcoming of 9902 cases of 26 published research wherein various breeds of sheep to assess the influence of the FecB gene on litter size utilizing additive, recessive, dominant, and co-dominant genetic models. The random effects model was used for data analysis according to the Cochran Q test and I2 quantity. Under additive (SMD = 0.528), dominant (SMD = 0.468) and recessive (SMD = 0.250) models, the significant effect (P<0.01) of FecB genotypes has been identified. Furthermore, under the co-dominant (SMD = -0.050, P = 0.3332) model, the association between FecB genotypes and litter size trait had not been detected. A growth in litter size by about 0.47 lambs (Dominant model) was associated with the first copy of the FecB gene and 0.25 lambs (Recessive model) with the second copy of this gene. Consequences of the current study support the idea that BMPR1B fundamentally influenced litter size and subsequently it may be utilized for Marker-assisted selection programmers for improved genetic merit of reproductive futures and furthermore insert this gene by crossbreeding in low prolific breeds may improve reproductive characteristics.

Sheep abortion – a roundtable discussion

Foreword Abortion takes a heavy toll on the sheep industry, not only economically, but in emotional terms too. Enzootic abortion in ewes is consistently the most frequent diagnosis followed in descending order by infection with Toxoplasma gondii, Campylobacter spp., Salmonella spp. and Listeria spp. Causes of abortion also lead to increased barren rates, and the birth of weak lambs, so the impact of these pathogens is greater than just abortion. Fortunately there are vaccines for the two most common causes of abortion, providing farmers and the veterinary surgeons advising them with effective and sustainable tools in the control of enzootic abortion and toxoplasmosis. The uptake of these vaccines, however, remains lower than might reasonably be expected. In this roundtable discussion the barriers to the implementation of the extant measures of abortion control were discussed and suggestions made as to how abortion can better be prevented.

Identification of lncRNAs Differentially Expressed during Natural and Induced Estrus in Sheep

Background: The manipulation of the estrous cycle or induction of estrus is a commonly used technique in sheep industry. The goal of this study was to identify and characterize differences of non-coding RNAs (lincRNAs) expression between induced estrus and natural estrus using the BGISEQ-500 plat form in 7 Mongolian sheep, which will provide insights into the regulation mechanisms of lncRNAs in different reproduction mode of sheep. Methods: During the late spring, ovarian, pituitary, hypothalamic, pineal and uterine tissue samples were collected from four artificially induced estrus and three naturally estrus Mongolian sheep. Total RNA was extracted from the five tissues using TRIzol reagent (Invitrogen) and treated with DNase I following the manufacturer’s instructions. A total of 35 sheep samples were sequenced using the BGISEQ-500 plat form. Bioinformatics methods were used to analysis expression difference analysis between groups, SNP and InDel, alternative splicing, lncRNA’s miRNA precursor prediction, lncRNA target gene and family prediction. Result: 211 novel lncRNAs were systematically identified using RNA-Seq technology. Meanwhile, we found that there are diversifications of lncRNAs in induced estrus vs. nature estrus of ewes. Therefore, we predict that, under the action of exogenous hormones, many physiological processes of ewes may be affected to varying degrees through the change of LncRNA to a variety of pathways.

First report on outbreaks of contagious ovine digital dermatitis in Sweden

Background Contagious ovine digital dermatitis (CODD) is considered widespread in the United Kingdom but was only recently reported in mainland Europe, as one outbreak in Germany. The disease can cause severe lameness in sheep and, if left untreated, can lead to total avulsion of the hoof capsule. CODD is considered to have multifactorial and polymicrobial aetiology, in which Treponema medium/Treponema vincentii phylogroup, Treponema phagedenis phylogroup and Treponema pedis are believed to play a significant role. Footrot and CODD have a close connection and footrot is considered an important risk factor for CODD. Case Lameness, mainly in lambs aged 1.5 months, was reported on a farm in Sweden in spring 2018. The animals showed no signs of footrot and the causative agent, Dichelobacter nodosus, was not found. CODD was suspected but not confirmed, and the clinical signs subsided when the animals were turned out to pasture. In February 2019, young lambs and ewes were lame again and this time CODD was diagnosed. After treatment, the whole flock was slaughtered later in 2019 due to CODD. In autumn 2020, CODD was diagnosed on another Swedish farm, this time as part of a mixed infection with D. nodosus. The animals were treated with footbaths in zinc sulphate 10% by the farmer, but lameness recurred soon afterwards. The animals were treated, but ultimately the whole flock was slaughtered. No connection was found between the two farms. Conclusion The first two outbreaks of CODD in Sweden have been diagnosed and are described in this case report. If it spreads, CODD could have a negative impact on the Swedish sheep industry in terms of animal welfare, production and antibiotic use.

A novel 2 bp deletion variant in Ovine-DRB1 gene is associated with increased Visna/maedi susceptibility in Turkish sheep

Visna/maedi (VM) is a multisystemic lentivirus infection of sheep that affecting sheep industry across the globe. TMEM154 gene has been identified to be a major VM-associated host gene, nevertheless, a recent study showed that the frequency of the VM-resistant TMEM154 haplotypes was very low or absent in indigenous sheep. Thus, the present study was designed to determine other possible co-receptors associated with VM. For this purpose, DRB1 gene, which is renowned for its role in host immune response against various diseases was targeted. A total number of 151 case–control matched pairs were constructed from 2266 serologically tested sheep. A broad range of DRB1 haplotype diversity was detected by sequence-based genotyping. Moreover, a novel 2 bp deletion (del) in the DRB1 intron 1 was identified. For the final statistic, the sheep carrying VM-resistant TMEM154 diplotypes were removed and a McNemar’s test with a matched pairs experimental design was conducted. Consequently, it was identified for the first time that the 2 bp del variant is a genetic risk factor for VM (p value 0.002; chi-square 8.31; odds ratio 2.9; statistical power 0.90) in the dominant model. Thus, negative selection for 2 bp del variant could decrease VM infection risk in Turkish sheep.

Does the Mutton Sheep Weather Index Insurance Promote the Mutton Sheep Industry?A Study based on the Endogenous Switching Regression Model

In 2018, as the first livestock weather index-based insurance product for grassland animal husbandry, the mutton sheep weather index insurance was officially listed as a subsidy agricultural insurance by the Government of the Inner Mongolia Autonomous Region, which was later in 2019 implemented throughout the XilinGol League of the autonomous region. Employing the endogenous switching regression model, this study investigates the factors influencing herdsmen's purchasing decisions, as well as the impact of mutton sheep weather index insurance on the mutton sheep industry scale, which are accomplished based on 308 survey data from herdsmen in the XilinGol League. The empirical results reveal that the age, age squared, pasture area and neighbors' purchasing intention constitute the significant influencing factors of the herdsmen's purchasing decisions, while the pasture area and net pastoral income affect the scale of mutton sheep farming prominently. Furthermore, according to the ATT results, the mutton sheep weather index insurance produces an insignificant impact on the sheep farming scale of herdsmen. The conclusions of this study suggest that the mutton sheep weather index insurance is not contrary to the cattle-increasing, sheep-reducing policy in the Inner Mongolia Autonomous Region, which also provide a solid theoretical basis for the promotion of the insurance throughout the autonomous region.

Ovine FABP4 Variation and Its Association With Flystrike Susceptibility

Flystrike is a major cost and a welfare issue for the New Zealand sheep industry. There are several factors that can predispose sheep to flystrike, such as having fleecerot, a urine-stained breech, and “dags” (an accumulation of fecal matter in the wool of the breech). The FABP4 gene (FABP4) has been associated with variation in ovine fleecerot resistance, with a strong genetic correlation existing between fleecerot and flystrike occurrence. In this study, blood samples were collected from sheep with and without flystrike for DNA typing. PCR-SSCP analyses were used to genotype two regions of ovine FABP4. Sheep with the A1 variant of FABP4 were found to be less likely (odds ratio 0.689, P = 0.014) to have flystrike than those without A1. The likelihood of flystrike occurrence decreased as copy number of A1 increased (odds ratio 0.695, P = 0.006). This suggests that FABP4 might be a candidate gene for flystrike resilience in sheep, although further research is required to verify this association.

A novel 2 bp deletion variant in Ovine-DRB1 gene is associated with increased Visna/maedi susceptibility in Turkish sheep

Visna/Maedi (VM) is a multisystemic lentivirus infection of sheep that affecting sheep industry across the globe. TMEM154 gene has been identified to be a major VM associated host gene, nevertheless, a recent study showed that the frequency of the VM-resistant TMEM154 haplotypes was very low or absent in indigenous sheep. Thus, the present study was designed to determine other possible co-receptors associated with VM. For this purpose, DRB1 gene, which is renowned for its role in host immune response activity against various diseases was targeted. A total number of 151 case-control matched pairs were constructed from 2266 ELISA tested sheep. A broad range of DRB1 haplotype diversity was detected by sequence-based genotyping. Moreover, a novel 2 bp deletion (del) in the DRB1 intron 1 was identified. For final statistic, the sheep carrying VM-resistant TMEM154 diplotypes were removed and a McNemar’s test with a matched pairs experimental design was conducted. Consequently, it was identified for the first time that the 2 bp del variant is a genetic risk factor for VM (p-value, 0.002; chi-square, 9.3; odds ratio, 2.9; statistical power > 0.93) in dominant model. Thus, negative selection for 2 bp del variant could decrease VM infection risk in Turkish sheep.