Effect of animal level factors on the semen quality in dairy breeds at National Animal Genetic Resources Center and Databank

Abstract

Dairy industry contributes greatly to the GDP and to the Global economy with a population of more than 270 million producing 700 tons of milk but due to land scarcity as a result of increased population , keeping of bulls for natural mating is un reliable .The government of Uganda introduced the use of improved breeding technologies such as Artificial Insemination which is done with imported semen and selected bulls at NAGRC & DB to produce semen for breeding to farmers but many complaints have been recorded from different farmers about poor conception rates following insemination of their cows using semen from this center which could be partly be blamed on number of factors among which are effects of animal level factors on semen quality which is a determinant of conception rates because identification of the factors which affect the spermatic production and the quality of the semen has a major importance in improvement of bull fertility. The aim of this study was to evaluate effects of animal level factors such as age, body condition score, body weight on progressive motility, overall motility, live dead ratio, semen morphology and concentration of bovine spermatozoa on Holstein Friesian bulls between 2 and 12 years of age during the period from October 2023 to June 2024. Semen samples were collected using an artificial vagina. Immediately after collection, laboratory examinations were made for all samples, which included finding out sperm concentration, live-dead ratio, progressive and overall motility. Sperm concentration was determined using a spectrophotometer. Total sperm count was calculated by multiplying ejaculate volume by sperm concentration, live dead ratio and morphology established by eosin nigrosine staining, progressive and overall motility evaluated using a computerized semen analyzer. For statistic evaluation of semen parameters, the average mean and standard deviation values were used and the bulls were divided into groups according to the age. The effect of animal level factors on the semen parameters was tested by one-way ANOVA using SPSS version 20 statistical program. the highest progressive motility was found in bull of 6 years with the highest overall motility in the bull of 8 years, lowest progressive motility was observed in 12 years and lowest overall motility in 10 years, highest live percentage was seen in bull of 2 years and the lowest live percentage in 12 years. Based on the results we can conclude that animal level factors had a significant influence on all monitored parameters in Holstein Friesian bovine semen.