Genetic variation in Nilagiri sheep, the only apparel wool breed in South India was studied using 25 FAO recommended ovine-specific microsatellite markers. The number of observed alleles ranged from 3 to 8 with a mean of 5 across all loci. The size of alleles ranged from 72 to 228 bp. The frequency of alleles ranged from 0.0104 to 0.5781. In total, 125 alleles were observed at the 25 loci studied. The effective number of alleles ranged from 2.18 to 6.49. The mean number of effective alleles was 3.84 across all loci. All the 25 loci were found to be highly polymorphic. The PIC values ranged from 0.4587 to 0.8277 with a mean of 0.6485. Of 25 microsatellites studied, 17 were in Hardy-Weinberg Equilibrium proportions. The observed heterozygosity ranged from 0.4222 to 1.000 with a mean value of 0.7610 whereas the expected heterozygosity ranged from 0.5415 to 0.8459 with a mean value of 0.7213. Except six loci, the other loci revealed negative within-population inbreeding estimates (F IS ) indicating excess of heterozygotes in the population of Nilagiri sheep.

Genetic variation in Barbari goats, a highly prolific breed distributed widely in the northern part of India, known for better milk and meat quality, was studied as a part of genetic characterization and conservation. The genomic DNA from 50 unrelated Barbari goats were amplified via PCR with a panel of 21 microsatellite markers, and resolved through 6 per cent denaturing polyacrylamide gel electrophoresis followed by silver staining. The number of alleles ranged from 4 to 11, with allele sizes ranging from 88 to 220 bp. The distribution of allele frequencies was between 0.0104 and 0.5208. Polymorphism information content varied from 0.5563 to 0.8348. The population was not in Hardy-Weinberg equilibrium for all except two microsatellite loci (ILSTS044 and ILSTS060). The observed heterozygosity ranged from 0.8478 to 1.0000 while the expected heterozygosity ranged from 0.6208 to 0.8509. Based on the results of the present study, there is a good scope for exploiting the genetic variability in the Barbari goats for further improvement of performance.

Indigenous ducks play a vital role in sustainable livelihood of the poor duck farmers. In Tamil Nadu, two popular indigenous duck varieties viz., Sanyasi and Keeri are being reared traditionally by the duck farmers under nomadic system. In the same way, Kuttanad ducks are popular in Kerala and Assam ducks are popular in Assam. The present research work was undertaken to study the genetic distance between and within the indigenous ducks and exotic duck breeds by using duck specific microsatellite markers. From the blood samples the genomic DNA was isolated and characterized genetically. With the molecular data, dendrogram was constructed. This revealed that, Keeri, Sanyasi, Kuttanad and Assam ducks formed the first group with White Pekin in the second group and Muscovy in the third cluster. Among the Indian duck varieties, Keeri and Sanyasi ducks of Tamil Nadu were found to be closer to each other as indicated by the genetic distance value of 0.11. However, within this group, 26.33 and 29.87 per cent of differentiation were noticed between Assam and Sanyasi and Assam and Keeri ducks respectively. Higher genetic distance value of 0.92 (92 per cent) was observed between two exotic ducks. Based on the genetic distance and genetic diversity between the indigenous ducks, the duck varieties of Tamil Nadu, Kerala and Assam may be classified as distinct breeds.

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The present study was aimed to investigate the effects of body weight and scrotal circumference on semen production traits of 136 crossbred Jersey bulls, which were maintained at three frozen semen stations of Tamil Nadu, India. Semen production traits such as semen volume, sperm concentration, mass activity, initial sperm motility, post-thaw motility and number of doses per ejaculate were taken for this study. The overall mean values for semen volume (ml), sperm concentration (millions per ml), mass activity (0 to 5 scale), initial sperm motility (per cent), postthaw motility (per cent) and number of doses per ejaculate were 4.18 ± 0.02, 1052.80 ± 7.26, 2.09 ± 0.07, 63.36 ± 0.00, 50.52 ± 0.00 and 215.50 ± 2.01 respectively. From this study, it revealed that the body weight and scrotal circumference of bulls significantly influenced all semen production traits except mass activity. Bulls having a body weight between 350 to 550 kg produced better quality semen and more number of frozen semen doses per ejaculate. When the scrotal circumference was >36 cm, majority of the semen production traits showed better values. The body weight was positively and significantly correlated with scrotal circumference, Semen volume and number of frozen semen doses produced per ejaculate. The scrotal circumference was positively and significantly correlated with semen volume, mass activity and number of doses per ejaculate; negatively and significantly correlated with initial sperm motiltiy.