Semen characteristics were collected from proven sires of Kagoshima prefecture. A total of 18,704 ejaculation records between February 1994 and February 2008 obtained from 118 bulls were used for analysis. Traits analyzed were volume per ejaculate (VOL, ml), sperm concentration (CON, ×10⁸/ml), number of sperm per ejaculate (NUM, ×10⁸) and sperm motility (MOT, %). Variance components were estimated by restricted maximum likelihood procedure under univariate repeatability animal model. Heritabilities were generally low and estimated to be 0.11 for VOL, 0.05 for CON, 0.09 for NUM, and 0.15 for MOT. Despite the low heritabilities, large variations and high accuracies were observed in predicted breeding values of bulls. Breeding values of MOT ranged from -11.6 to 9.0%, and of NUM indicated standard deviation of 7.3×10⁸. These variations can be used to change semen traits genetically.

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To determine genetic diversity and relationship of Bhutanese indigenous cattle, we analyzed mtDNA D-loop sequence of cattle from three populations of Bhutanese native cattle (Thrabum) and two Bhutanese populations each of Tibetan (Goleng) and Indian (Jaba), and together with a Nepalese cattle population. Although Bhutanese native cattle morphologically reveal them as B.indicus with the prominent hump, the three Thrabum populations included both B.indicus and B.taurus types of mtDNA haplotypes. Almost all of Bhutanese indigenous populations included both haplotypes assigned to either I1 or I2 clade of B.indicus with adequate frequencies, while B.taurus type of haplogroups of T1, T3 and/or T4 clades were observed in all the five Bhutanese indigenous populations. The result indicated that indigenous cattle of Bhutan are admixture of B.taurus and B.indicus, and that ancient taurine had contributed in the formation of Bhutanese native cattle.

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