TRENDS AND GENETIC EVALUATION OF ECONOMIC TRAITS IN FRIESIAN CATTLE MANAGED UNDER EGYPTIAN CONDITIONS

This study aimed to investigate the impact of both genetic and non-genetic factors on the productive and reproductive traits of Friesian cattle, as well as to track genetic and phenotypic trends over the years of calving in Egypt. Records were gathered from the lactation records of Friesian cattle at the Sakha Experimental Station. During a span of ten years, from 2008 to 2017, which situated northwesterly of the Nile Delta in the Kafr El-Sheikh governorate. The herd is managed by the Animal Production Research Institute (APRI), which operates under the Agricultural Research Center (ARC) in Giza, Egypt. In total, 1,609 lactation records were collected from 384 Friesian cows, which were 290 dams and 95 sires offspring. Friesian cattle productive traits include Total Milk Yield (TMY), 305-Day Milk Yield, Lactation Length (LL), Days Open (DO), and Calving Interval (CI). A univariate animal model was used to assess variance components, heritability, and repeatability, using Wombat software. The productive qualities examined had moderate direct heritability (h2a) estimations. For 305-DMY, TMY and LL were estimated to be 0.28 and 0.30, respectively. Current h2a estimates implied that selective breeding efforts in future generations can result in genetic improvements in TMY, 305-DMY, and LL traits. In terms of reproductive traits, h2a estimates were low. The estimate of h2a for DO was 0.02 and for CI was 0.03. Better management strategies can help reduce environmental variation, while also improving reproductive features in medium and high-milk-producing cows. The genetic trend (GT) for TMY and 305-DMY fluctuated over time, with some years showing an improvement in these features and others showing a decline. In terms of reproductive qualities, the anticipated negative GT was attained in most research periods for both DO and CI, with negative annual genetic gains of around -0.09 and -0.14 days/year for DO and CI, respectively. To improve herd productivity, it's important to enhance both genetic potential and management practices. These aspects are crucial for overcoming low heritability in reproductive traits and increasing the overall herd performance.