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Aim: This study aims to evaluate genetic and non-genetic factors influencing semen production potential of Gir bulls. Materials and Methods: Data on semen quantity (n=6911) and quality (n=466) available from January 2011 to December 2018 at BAIF's frozen semen station, Jind, Haryana, India, were utilized for the study. Factors, namely, season of collection, age at collection, and bull (random effect) were studied for their effect on quantitative and qualitative semen traits. Least square means for the traits were obtained using a general linear model. The effect of age within bull for repeatable traits was analyzed using a longitudinal model with age as the control variable. Multivariate analysis using mixed repeatability model equation was utilized to estimate bull effect correlation (genetic + permanent environmental correlation), phenotypic correlations, and repeatability. Results: The overall least square means of ejaculate volume, sperm concentration, total sperms, initial and post-thaw motility, hypo-osmotic swelling test, and acrosome integrity of frozen semen were 6.62±0.03 ml, 1.22±0.01 109/ml, 8.09±0.05 109/ml ejaculate, 75.78±0.001%, 55.92±0.0001%, 55.13±0.005%, and 71.08±0.001%, respectively. The season of the collection showed a significant effect on volume, concentration, total sperm, and initial motility. The performance of bulls was superior in summer season, followed by winter and monsoon. Increase in semen attributes during summer season was due to the effect of lower temperature on sensitive stages of spermatogenesis. Age at collection had a significant effect on all semen traits. Volume and total sperm count showed increasing trend while concentration showed a decreasing trend with an increase in age. Motility and quality traits did not show any particular pattern. Individual bulls showed differences in all the semen performance traits with age. The repeatability of the traits ranged from 0.04 (HOST) to 0.58 (acrosome integrity). Bull effect correlation ranged from –0.73 (initial motility and acrosome integrity) to 0.93 (HOST and acrosome integrity). Conclusion: Individual bulls showed variation in traits measured over age. The result of the study could be utilized in suggesting suitable management plans to achieve the desired profit by improving semen quality in Gir bulls.

The objective of the study was to identify the factors affecting variation in conception rate of buffaloes inseminated by Murrah bulls’ frozen semen under field conditions. Total of 18,396 insemination records pertaining to 11,793 buffaloes that were inseminated artificially at BAIF’s field AI centers during the period of June 2010 to December 2014 in 3 states. Logistic regression analysis was used to compute the odds ratio and probability of conception rate. Records were classified according to agroclimatic zones, lactation order, season of insemination and body condition score. Agroclimatic zones, lactation order and body condition score showed significant variation. The overall conception rate was 48.01%. Conception rate of western plain zone of Uttar Pradesh was higher than other zones under study. Body condition score 3 was favourable where probability of conception was 0.51. Conception rate of first parity buffaloes was lower than other parities with the probability of 0.46. Conception rate increased in second parity with probability 0.52. Highest conception rate was found in fourth parity with probability 0.53. There was marginal difference between second to fifth parity. Season of insemination did not affect conception rate, however, the distribution of artificial inseminations was higher during the favourable season than that during lean-season. It could be inferred that the factors like agroclimatic zones, lactation order and body condition score should be considered while evaluating the conception rates in buffaloes.

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Semen characteristics of 97,112 ejaculates from 399 adult bulls of 2 exotic breeds, 2 indigenous breeds and crossbred sub-populations with 50% and 75% of exotic inheritance, and of 3,293 ejaculates from 292 test bulls were analysed. The traits considered were: ejaculate volume, sperm concentration, total number of sperms, initial and post-thaw motility, and a theoretical number of doses produced from each given ejaculate. The objective was to measure the semen production potential of different genetic groups of cattle breeds, to identify factors affecting semen production and quality traits, and to assess the correlation between semen characteristics measure on test and adult bulls. A linear mixed model was used to evaluate the effect of different fixed and random effects. For adult bulls, the first ejaculate of a bull on a particular day and longer collection intervals lead to better characteristics for all the parameters but short collection interval with two ejaculate on particular day lead to a larger number of total semen doses produced without hampering semen quality. Repeatability estimates for semen traits were found to be low to moderate. Low to moderate and negative bull correlation was observed between concentration and volume in all the breed groups while the correlations of bull effects of the two motility traits were comparatively large. The moderate to high correlation for all semen traits between their testing and when they are adult highlights the importance of andrology evaluation in predicting future semen production of AI bulls in order to discard the less productive bulls.

Background: The production of higher number of quality semen doses from the indigenous bulls is required to mitigate the issue of declining population of indigenous cattle breeds. To make the semen production more efficient, the knowledge of factors affecting the semen production is of utmost importance. However, studies on different indigenous breeds are scarcely available and very little information is available on effect of ejaculate number, collection interval, semen collector etc. The present investigation was hence focused to study the effect of different management and environmental factors affecting semen production traits in indigenous breeds. Methods: Semen data comprising of 15,435 ejaculates from 60 bulls of 10 indigenous cattle breeds were analysed for semen production traits. Prior to the analysis, data on initial motility was transformed using the arcsine transformation. Least square analysis was carried out using “lm” function while ANOVA (Type III sum of square) and Duncan’s multiple range test were computed using “car” and “agricolae” packages from R statistical software. Result: The overall means for the semen production traits: ejaculate volume, sperm concentration, total sperm, initial motility and total motile sperm were 5.62±0.041 ml, 1.42±0.51× 109/ml, 7.96±0.25× 109/ejaculate, 74.77±0.002% and 5.92± 0.11 × 109/ejaculate, respectively. All traits were significantly affected by order of ejaculate, collection interval, age at collection, breed, semen collector, season and year of collection except collection interval which had no effect on motility. Except initial motility, semen characters showed quadratic pattern over the age. Results of the study would help in suggesting suitable management and breeding plans for semen production traits.

Vitamin A is essential for human health, but current intake levels in many developing countries such as India are too low due to malnutrition. According to the World Health Organization, an estimated 250 million preschool children are vitamin A deficient globally. This number excludes pregnant women and nursing mothers, who are particularly vulnerable. Efforts to improve access to vitamin A are key because supplementation can reduce mortality rates in young children in developing countries by around 23%. Three key genes, BCMO1, BCO2, and SCARB1, have been shown to be associated with the amount of β-carotene (BC) in milk. Whole-genome sequencing reads from the coordinates of these 3 genes in 202 non-Indian cattle (141 Bos taurus, 61 Bos indicus) and 35 non-Indian buffalo (Bubalus bubalis) animals from several breeds were collected from data repositories. The number of SNP detected in the coding regions of these 3 genes ranged from 16 to 26 in the 3 species, with 5 overlapping SNP between B. taurus and B. indicus. All these SNP together with 2 SNP in the upstream part of the gene but already present in dbSNP (https: / / www .ncbi .nlm .nih .gov/ projects/ SNP/) were used to build a custom Sequenom array. Blood for DNA and milk samples for BC were obtained from 2,291 Indian cows of 5 different breeds (Gir, Holstein cross, Jersey Cross, Tharparkar, and Sahiwal) and 2,242 Indian buffaloes (Jafarabadi, Murrah, Pandharpuri, and Surti breeds). The DNA was extracted and genotyped with the Sequenom array. For each individual breed and the combined breeds, SNP with an association that had a P-value <0.3 in the first round of linear analysis were included in a second step of regression analyses to determine allele substitution effects to increase the content of BC in milk. Additionally , an F-test for all SNP within gene was performed with the objective of determining if overall the gene had a significant effect on the content of BC in milk. The analyses were repeated using a Bayesian approach to compare and validate the previous frequentist results. Multiple significant SNP were found using both methodologies with allele substitution effects ranging from 6.21 (3.13) to 9.10 (5.43) µg of BC per 100 mL of milk. Total gene effects exceeded the mean BC value for all breeds with both analysis approaches. The custom panel designed for genes related to BC production demonstrated applicability in genotyping of cattle and buffalo in India and may be used for cattle or buffalo from other developing countries. Moreover, the recommendation of selection for significant specific alleles of some gene markers provides a route to effectively increase the BC content in milk in the Indian cattle and buffalo populations.

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