Impact of Subclinical Mastitis on Milk Quality in Different Seasons

Abstract

This study was carried out to evaluate the influence of subclinical mastitis on chemical constituents of cow’s milk samples in different seasons; which collected from 444 apparently healthy Holstein Frisian dairy animals during the period of December 2016 to November 2017 in a private dairy farm located in Fayoum district, Egypt. The results of chemical analysis of the milk samples along the four seasons of the year which done by the Lactoscan SLC milk analyzer device revealed that; the values of mean for (Fat%, Protein%, SNF%, Lactose%, Salt% and SCC/ml) in winter were (2.22±0.06, 2.90±0.08, 7.79±0.22, 4.14±0.12, 0.72±0.02 and 6.9×105±1.9×104 respectively).While the mean values of the same parameters in spring were (2.72±0.23, 2.58± 0.22, 6.93±0.58, 3.67±0.31, 0.64±0.05 and 9.2×105±7.7×104 respectively). In the summer, the mean values of (Fat%, Protein%, SNF%, Lactose%, Salt% and SCC/ml) were (2.35± 0.24, 2.80 ±0.28, 7.55±0.76, 4.00±0.40, 0.70±0.07 and 7.7×105±7.7×104 respectively), while the mean values in the autumn were (2.89±0.09, 2.69±0.08, 7.25±0.21, 3.84±0.11, 0.67±0.02 and 11.0×105±3.2×104 respectively). The analysis of findings specified that; there is a significant difference (P<0.05) in fat % and SCC between winter and autumn, however there is a significant difference (P<0.05) between (winter and autumn) and (winter and spring) in the parameters of protein, SNF and lactose content. The results reveal that there is a strong negative correlation between SCC and fat %; however there is a strong positive correlation between SCC and salt %.