Non-genetic Factors Influence Birth Weight of Friesian and Friesian x Fipa Cattle Calves in One Highland Farm of Tanzania

Calving records were extracted from record books at TALIRI Uyole farm from 2013 - 2022, to study and determine the influence of breed, sex, season of birth, and year of birth on weight at birth of pure Friesian and its crosses (F1 Friesian x Fipa and 75% Friesian x Fipa) calves which, are grazed under natural pasture. The least squares mean of BWT in Friesian, F1 and 75% calves were 25.51±0.98 kg, 26.45 ± 1.23 and 25.26 ± 0.94, respectively. It was observed that sex of calf and year of birth had significant (P<0.05) influence on birth weight, the males being heavier than the females by 1.86 kg of the mean birth weight. Breed and season of birth of calves were not associated (P>0.05) with variation in mean birth weight of its crosses at birth, whereas variations on BWT at birth were noted in F1, which had higher BWT compared to other breed/cross, and calf born in the wet season showed slightly higher BWT than calves born in the dry season. Under natural pasture grazing, the available fodder was of poor quality, and no agronomic management practices were followed, whereas it was reverse in the wet season, thus the nutrient demand for body maintenance, reproduction, and production activities are impaired.