Related Experiment Video
Updated: Aug 5, 2026
Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid
Published on: August 8, 2017
Non-genetic determinants and interaction effects on semen quality and production efficiency in Mehsana buffalo bulls:
N S Dangar1, B P Brahmkshtri2, P A Patel3
1College of Veterinary Science and A. H, Kamdhenu University, Bhuj, Gujarat, 370001, India. drnik2487@gmail.com.
Abstract:
Understanding the environmental and management-related determinants of semen production is essential for optimizing artificial insemination programs in buffalo breeding. This study comprehensively evaluated the influence of major non-genetic factors and their interactions on semen quality and semen production traits in Mehsana buffalo bulls using one of the largest repeated-record field datasets reported for this breed. A total of 55,071 ejaculates collected from 244 bulls maintained at two organized semen stations in Gujarat, India, were analyzed. Semen volume, sperm concentration, initial sperm motility, post-thaw sperm motility, and the number of semen doses produced per ejaculate were evaluated using repeated-record linear mixed-effects models fitted by restricted maximum likelihood (REML), with bull included as a random effect and within-bull correlations modeled using a first-order autoregressive covariance structure. Age at semen collection, period of semen collection, and ejaculate number consistently influenced all semen traits, whereas farm and season exhibited trait-specific effects. Semen volume and semen dose yield generally increased with advancing age, peaked between 3 and 5 years (197-202 semen doses per ejaculate), and declined thereafter. The first ejaculate consistently produced greater semen volume, sperm concentration, and semen dose output than the second ejaculate (248 vs. 115 semen doses per ejaculate). Significant interactions among farm, age, season, and ejaculate number demonstrated that semen traits responded differently across management environments and physiological stages, supporting age-specific bull utilization and optimized semen collection schedules in organized breeding programmes. By integrating a large longitudinal dataset with repeated-record mixed-model analyses, this study provides a comprehensive characterization of non-genetic sources of variation affecting semen production traits in Mehsana buffalo bulls. The findings offer an evidence-based framework for optimizing bull utilization and semen collection strategies in organized breeding programs while highlighting the need for future investigations integrating fertility, physiological, environmental, and genomic information to elucidate the mechanisms underlying the observed associations.
Related Concept Videos
02:27Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
01:11Testing a Claim about Mean: Known Population SD
Estimating a population mean requires the samples to be distributed normally. The data should be collected from the randomly selected samples having no sampling bias. The sample size needed to be higher than 30, and most importantly, the population standard deviation should be already known.
In most realistic situations, the population standard deviation is often unknown, but in rare circumstances, when it...
01:20Mate Choice