Multivariate analysis of morphometric traits of Malaimadu cattle-autochthonous draft cattle of south India.

Malaimadu cattle is a less explored indigenous cattle germplasm reared in the Western Ghats area of Tamil Nadu, south India. This study aimed to analyze the morphological structure of the Malaimadu cattle using a multivariate approach that explains and best represents body conformation. Sixteen body measurements were obtained from 156 adult female cattle from their native breeding tract. The Nearest Neighbor Method of Hierarchical Cluster analysis was used to group the morphometric traits into clusters. Pearson's coefficients of correlation (r) were estimated to determine the phenotypic correlations between different body measurements. Traits were analyzed using varimax rotated principal component analysis (PCA) with Kaiser normalization. Cluster analysis categorizes morphometric traits into two distinct clusters with the first cluster formed by traits related to horns and face, while the second cluster denotes general body conformation. Out of 120 phenotypic correlations, 55 were significant of which 51 were positive correlations. The estimated correlation coefficient ranges between - 0.50 (body length and face width) to 0.85 (chest girth and body weight). PCA extracted six components representing 70.19% of the total variance, while the first principal component comprises chest girth (CG), body weight (BW), height at wither (HW), and Paunch girth (PG) alone accounts for 23.70% thereby describing the general size and shape of the animal. The multivariate approach has proven to be effective in differentiating Malaimadu cattle from other indigenous breeds of south India with clear morphometric differences that help in identifying the pure phenotype for future propagation and also for devising breeding strategies.

Non-genetic effects and repeatability estimates of semen production traits in Murrah buffalo bulls.

The objectives of this study were to determine the repeatability estimates and the effect of ejaculate, season, period, age, and bull on semen production traits in Murrah buffalo bulls maintained in an organized semen station. A data set comprising 54,268 ejaculates from 76 Murrah buffalo bulls collected across 12 years were analyzed. The analysis of variables included non-genetic factors as the fixed effects and bull as the random effect. The repeatability was estimated by the restricted maximum likelihood method (REML) using WOMBAT program. The overall least-squares means for semen volume, sperm concentration, total sperm/ejaculate, mass activity, individual motility, post-thaw motility, and frozen semen straws/ejaculate were 2.65 ml, 1222.04 million/ml, 3030.10 million, 2.64, 67.45%, 51.73%, and 128.80 doses. The repeatability estimates were 0.27, 0.25, 0.22, 0.28, 0.34, 0.27, and 0.23, respectively. The studied non-genetic factors influenced (P < 0.01) all seminal traits. Likewise, variation (P < 0.01) due to individual bull was also observed. The first ejaculate was superior in terms of ejaculate volume, sperm concentration, total sperm/ejaculate, and frozen semen straws than the second ejaculate. The south-west monsoon and summer seasons were the best seasons with better semen quality and frozen semen production. Compared to the remaining periods, during Period V (2014-2016), greater values for most seminal traits were found. Bulls above 8 years of age expressed higher semen production than the younger bulls below 4 years, whereas the best performance was observed in the age group of 12 years and above. The repeatability estimates were low to moderate ranging from 0.22 for total sperm/ejaculate to 0.34 for individual motility. A significant (P < 0.01) positive correlation was observed between the seminal traits except the negative correlation in semen volume and total sperm/ejaculate. It was concluded that all the non-genetic factors considered in this study exerted influence on studied seminal traits. Therefore, appropriate management practices can be applied to improve semen quality and quantity.

Genetic evaluation of semen production potential in Indigenous bulls using random regression models in a Bayesian framework.

Genetic potential of indigenous bulls with respect to semen production traits over the age of the bulls at semen collection was analyzed using random regression models (RRMs). Data pertaining to 59,641 ejaculates from 189 bulls of 18 indigenous breeds collected from BAIF (Bharatiya Agro Industries Foundation) was utilized for this study. Six semen production traits, viz., ejaculate volume (EV, ml), sperm concentration (SC, 109/ml), initial sperm motility (ISM, %), post-thaw motility (PTM, %), the total number of spermatozoa per ejaculate (TNS, 109/ejaculate), and the theoretical number of semen doses (TNSD) were studied. Univariate and RRM were used to obtain variance components and genetic parameter estimates. Two hundred thousand Gibbs samples were generated for each trait with a burn-in of 20,000 and thinning interval of 50 in a Bayesian framework. Legendre polynomials with orders of fit up to 5 for additive and permanent environmental effects were used. RRM modeled the heritability and repeatability for all ages between 3 and 10 years (productive lifespan). Heritability estimates ranged from 0.18 to 0.36, 0.18 to 0.45, 0.02 to 0.06, 0 to 0.001, 0.09 to 0.32, and 0.14 to 0.42 while the repeatability estimates ranged from 0.41 to 0.72, 0.36 to 0.79, 0.04 to 0.10, 0 to 0.001, 0.37 to 0.56, and 0.32 to 0.57 for EV, SC, ISM, PTM, TNS, and TNSD, respectively. Variability of estimates over the age of the bulls obtained through RRM could be useful to further refine the breeding program for age at selection, deciding the production period and age at culling.

A rare chromosomal polymorphism in a Kangayam bull (Bosindicus) of south India.

A chromosomal polymorphism was detected on karyological screening of Kangayam breeding sires prior to subjecting them for frozen semen collection. One bull possessed the chromosomal complement 2n = 60, consisting of 58 acrocentric autosomes, one large sub-metacentric X-chromosome, and one small acrocentric Y-chromosome with a small visible p-arm, which was further confirmed using CBG- and GTG-banding. This polymorphism was attributed to a heterochromatin variation of the acrocentric Y-chromosome routine in the Bosindicus Linnaeus, 1758 cattle.

Ascertaining the paternal lineage in crossbred calves.

Karyotyping is one among the culling parameter used for taking up culling decisions. Cytogenetic screening of breeding bulls has been recommended to screen for chromosomal abnormalities before semen production in artificial insemination. The chromosomal analysis of a Holstein Friesian crossbred bull revealed the presence of acrocentric Y-chromosome, which was further confirmed by CBG banding. The shape of the Y-chromosome determining that male line used for crossbreeding was from indigenous origin. Karyotyping is a best and reliable technique for the identification of crossbred calves born to the indigenous bulls.

Genetic characterization of Barbari goats using microsatellite markers.

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.