No Association of Prolactin Receptor (PRLR) Gene and litter size in Gaddi Goat Breed Reared under Migratory System in Western Himalayan Ranges of Himachal Pradesh

Gaddi is the predominant Indian goat breed also known as “White Himalayan goat”, constituting 60-65% of total goats in the state of Himachal Pradesh. The polymorphism of prolactin receptor (PRLR) gene was found to have relationship with prolificacy in goats. In present study, polymorphism of intron 2 region of PRLR gene was investigated in Gaddi goats (n = 89) using PCR-SSCP and DNA sequencing approach. PCR-SSCP assay of 176 bp amplicon of intron 2 region of PRLR gene revealed polymorphism with three types of genotypes viz., AA, AB and BB with genotypic frequencies as 0.31, 0.55 and 0.14, respectively. The allelic frequency of alleles A and B were 0.59 and 0.41, respectively in all the screened goat population. Genetic diversity analysis revealed the value of Ne, Hobs, Hexp and PIC were 1.96, 0.52, 0.49 and 0.37, respectively. The Ne and Hobs values also indicated that sufficient genetic variation exists at the studied locus. FIS estimate was observed as -0.15 indicating heterozygous excess at studied locus. DNA sequencing of amplified product revealed one nucleotide mutation (T92C) in intron 2 region of PRLR gene. The mean litter size in AA, AB and AB genotypes were 1.27±0.12, 1.41±0.09 and 1.84±0.26, respectively. No significant (P>0.05) associations of PRLR genotypes with litter size were observed. Effect of season and parity were also found to be non-significant (P>0.05) on litter size. Consequently, the study on additional data based on more number of animals in diversified flock should be carried out for future association studies.

Postnatal developmental anatomy of testes and epididymis of Gaddi goats / Desarrollo anatómico postnatal de los testículos y epidídimo de cabras Gaddi

The study revealed that the testes of one-day-old Gaddi goats have descended in the scrotum along with adnexa. They were elongated compressed latero-medially and became ovoid during their postnatal growth and morphogenesis. The two testes were not different significantly in their weight and measurement. The average weight which was about 2.9 gm at birth grew to 107 gm (40X) in pubertal animals and nearly maintained it during the post-puberty (113 g). The mean length (1.46 cm), width (0.85 cm) and thickness (0.62 cm) also grew by 47, 60, and 83 times, respectively. In post-pubertal animals it measured 7.06 x 5.20 x 5.10 cm. The study indicated a very fast growth of the testes from birth to puberty, which did not alter significantly after that. A relatively much faster growth in thickness and width over the length was the reason behind the change of the morphology from more elongated shape at birth to ovoid shape on maturity. The mediastinum testis was grossly discernible in the testis even at birth. Epididymis was identifiable into caput, corpus and cauda. The gross linear mensuration of these components did not differ in the caput and cauda regions on either side, whereas the length of corpus was more on the left side in all age group of animals. The growth curve revealed a continuous growth of all segments, but the fastest growth occurred in the early postnatal life (at 12­18 month age).

El estudio reveló que los testículos de las cabras Gaddi, de un día de edad, descienden al escroto junto con sus anexos. Se elongaron en dirección latero-medial y convirtieron en ovoides durante su crecimiento postnatal y en la morfogénesis. Los dos testículos no fueron significativamente diferentes en su peso y medidas. El peso promedio fue aproximadamente de 2,9 g al nacer, y aumentó a 107 g (40X) en animales púberes y casi mantuvo su peso durante la post-pubertad (113 g). La longitud (1,46 cm), ancho (0,85 cm) y espesor (0,62 cm) también crecieron unas 47, 60 y 83 veces, respectivamente. En los animales post-puberales las medidas fueron de 7,06 x 5,20 x 5.10 cm. Se observó un crecimiento muy rápido de los testículos desde el nacimiento hasta la pubertad, sin alterarse de manera significativa posteriormente. Un crecimiento relativamente mucho más rápido en espesor y anchura, sobre la longitud, fue la razón detrás del cambio de la morfología desde la forma más alargada, presente en el nacimiento, a la forma ovoide de la madurez. El mediastino testicular fue claramente identificado en el testículo, inclusive en el nacimiento. En el epidídimo se identificaron las porciones de la cabeza, cuerpo y cola. La medición lineal de estos componentes no difirió en las regiones de la cabeza y cola de cada lado, mientras que la longitud del cuerpo fue mayor en el lado izquierdo en todos los grupos. La curva de crecimiento reveló un crecimiento continuo de todos los segmentos, pero el mayor crecimiento se produjo en la vida postnatal temprana (entre los 12 y 18 meses).