The semen quality of bucks affects the reproduction performance of the herd and is influenced by genetic and non-genetic factors. Heat shock protein 70 (HSP70) is considered as an important gene affecting semen quality traits. The objectives of this study are to find single nucleotide polymorphisms in HSP70 coding region and their association with semen quality traits on Boer and Boer cross bucks. DNA isolated from 53 goats (36 pure South African Boer and 17 Boer crosses) was subjected to PCR amplification of the exon 1 region of the caprine HSP70 gene. Single-strand conformation polymorphism (SSCP) was used to detect polymorphisms and the variant DNA fragments were sequenced. Two synonymous SNPs (74A>C (ss836187517) and 191C>G (ss836187518)) were detected. Qualities of fresh and post-thaw semen were evaluated for sperm concentration, semen volume, sperm motility and velocity traits, live sperm percentage, and abnormal sperm rate. The C allele of ss836187517 and G allele of ss836187518 were at higher frequencies in both the breeds. The C allele of ss836187517 appeared to be the favorable allele for semen concentration, progressive motility of fresh semen, and motility and sperm lateral head displacement of post-thaw semen. A negative overdominance was observed for ss836187517 alleles on velocity traits of post-thaw semen. The C allele of ss836187518 was favorable for sperm concentration and progressive motility. Results herein suggest that the SNPs in HSP70 may affect on semen quality in tropical regions and specially on the potential of semen for freezing.

No abstract

The present study aimed to investigate single-nucleotide polymorphisms (SNPs) of caprine FSHβ and caprine LHβ genes and to determine effects of the SNPs on fresh and post-thaw semen quality traits of Boer and Boer-crossbred bucks. The single-strand conformation polymorphism analysis and comparative sequencing revealed three SNPs in exon 3 of caprine follicle-stimulating hormone beta (FSHβ), including, three SNPs; 200A > G (FSHβ3-a), 226T > C (FSHβ3-b), and 237A > G (FSHβ3-c), while two of them (FSHβ3-a and FSHβ3-b) were novel. Furthermore, one SNP in exon 2 of luteinizing hormone beta (LHβ) (207T > C) (LHβ2) was detected. The associations of the four detected SNPs with quality traits of fresh and post-thaw semen were evaluated. Analyses of variance revealed significant association of the candidate genes with libido and semen quality traits. The three SNPs of FSHβ3 had significant effect on libido, progressive motility, and abnormality of fresh semen (P < .05), and on the motility, velocity, and viability traits of post-thaw semen (P < .05). LHβ2 polymorphism only showed association with sperm viability of post-thaw semen. The results of the present study suggest that the SNPs in caprine FSHβ and LHβ are associated with semen quality of male goats. Highlights. Three SNPs were found in exon 3 of FSHβ in which two of them were novel. . An SNP was found in exon 2 of caprine LHβ.. No SNP was detected in the 5 ′ -UTR, exon 1, and part of intron 1 regions of FSHβ and exon 3 of LHβ. . The SNPs of FSHβ3 had significant effect on motility and abnormality of fresh semen and motility, velocity, and viability of post-thaw semen. . LHβ2 polymorphism only showed association with sperm viability of post-thaw semen.

There are limited studies on the effects of transportation stress and stocking density under tropical conditions and their interactions with aging and muscle types on carcass and meat quality characteristics of goat. The present study investigated the effects of transportation and stocking density on carcass characteristics and meat quality traits of Longissimus dorsi, and Semimembranosus muscles in Boer goats. Thirty 1-year-old Boer goats, divided into two groups, were transported by road for 3.5 h, with density of 0.4 m 2 and 0.2 m 2 per animal, respectively; a third group which was not transported served as control. Meat pH, drip loss, cooking loss, tenderness and colour were measured from samples of the muscles. The transported goats had significantly lower carcass shrinkage, glycogen content, drip loss, tenderness, lightness, yellowness, hue-angle and chroma values compared to the non-transported group. In contrast, they showed significantly higher cooking loss and redness than the non-transported goats. Goats transported in high stocking density showed significantly (p < .05) higher live weight loss and lower dressing-out percentage than those in low stocking density. This study indicated that higher stocking density at pre-slaughter transportation increased shrinkage loss and deteriorated meat quality of goats. Therefore, using an appropriate density during transportation should be considered. ARTICLE HISTORY