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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.