Mutation studies in different prolific sheep breeds have shown that the transforming growth factor beta super family ligands viz. the growth differentiation factor 9 (GDF9/FecG), bone morphogenetic protein 15 (BMP15/FecX) and associated type I receptors, bone morphogenetic protein receptor (BMPR1B/FecB), are major determinant of ovulation rate and consequent increase in litter size. The Garole sheep is a highly prolific sheep breed of India. Characterization of fecundity genes in these animals could substantially improvise the breeding programme in these animals as well as other sheep breeds of the region. The present study was therefore designed with the objective of polymorphism study of fecundity genes in these prolific microsheep. A total of 11 point mutations were detected by polymerase chain reaction (PCR)-based method. A competitive technique called tetra-primer amplification refractory mutation system-PCR was adapted to type a total of ten points of two ovine fecundity genes (GDF9 and BMP15). The FecB locus of the BMPR1B gene and G1 locus of GDF9 gene were found to be polymorphic. In FecB locus, two genotypes, wild type (FecB(+)) and mutant (FecBB), were detected with allele frequencies of 0.39 and 0.61, respectively. At G1 locus, two genotypes, mutant (A) and wild types (G) were detected with allele frequencies of 0.18 and 0.82, respectively. This study reports Garole sheep as the fourth sheep breed after Belclare/Cambridge, Lacaune and Small-tailed Han sheep, where coexisting polymorphism has been found in two different fecundity genes (BMPRIB and GDF9 genes).

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The accurate prediction of male fertility is of major economic importance in the animal breeding industry. However, the results of conventional semen analysis do not always correlate with field fertility outcomes. There is evidence to indicate that mammalian fertilization and subsequent embryo development depend, in part, on the inherent integrity of the sperm DNA. Understanding the complex packaging of mammalian sperm chromatin and assessment of DNA integrity could potentially provide a benchmark in clinical infertility. In the era of assisted reproduction, especially when in-vitro fertilization or gamete intrafallopian transfer or intracytoplasmic sperm injection is used, assessment of sperm DNA integrity is important because spermatozoa are not subjected to the selection process occurring naturally in the female reproductive tract. Although sperm DNA integrity testing measures a significant biological parameter, its precise role in the infertility evaluation in farm animals remains unclear. In this review, the earlier findings on sperm DNA integrity in relation to male fertility are compiled and analyzed. Furthermore, the causes and consequences of sperm DNA damage are described, together with a review of advances in methods for detection of sperm DNA damage, and the prognostic value of sperm DNA quality on male fertility.

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