A RESEARCH ON MILK YIELD, PERSISTENCY, MILK CONSTITUENTS AND SOMATIC CELL COUNT OF RED HOLSTEIN COWS RAISED UNDER MEDITERRANEAN CLIMATIC CONDITIONS

H. Yilmaz, A. Koc

Abstract: Phenotypic and genetic parameter estimation of lactation length (LL), 305 days milk yield (305-dMY) and persistency traits (P2:1, P3:1, P3:2 and PTomax) of Red Holstein (RH) cows reared at a dairy cattle farm under the Mediterranean climatic conditions were estimated. In addition, the effects of environmental factors on milk constituents and somatic cell count (SCC) of RH were determined. The averages of LL, 305-dMY, P2:1, P3:1, P3:2 and PTomax calculated from 362 lactation records were 353.0±3.73 d, 7652.8±80.68 kg, 86.9±0.77%, 62.1±1.12%, 70.7±1.01% and 5.1±0.05, respectively. The heritabilities estimated by using individual animal model for these traits were determined to be 0.14±0.08, 0.44±0.06, 0.19±0.07, 0.31±0.07, 0.28±0.07 and 0.23±0.07, respectively. The averages of milk protein content (MPC) and Log10SCC for RH cows calculated from the analysis of 202 milk samples were 3.2±0.03% and 63.753 cells/mL, respectively. It can be said that RH cows had higher milk yield and better udder health status than some other breeds reared in the region. Due to higher temperature and relative humidity in summer under the Mediterranean climatic conditions, some precautions need to be taken against heat stress on this form and the dairy farms in the region.

Keywords: 305-days milk yield; heritability; milk protein content; persistency; somatic cell count

Date published: 2019-01-17