Somatic Cell Count Evaluation in Early Lactation between Primiparous and Multiparous Bos indicus Cows

Abstract

Using Bos indicus cows, a study examined the relationship between somatic cell count (SCC) and milk yield. For this study, one hundred fifty cows (Primiparous, PM, 75 and Multiparous, MP 75) in early lactation (days in milk, PM =134 ± 3; MP = 136 ± 5), milk production (9,88 kg/d, on average) of the creole breed Gyr lechers were enrolled. Before being assigned to each treatment, the SCC values were lower than 220,000 cells/mL, on average. All cows were maintained to graze daily on Megathyrsus maximus and supplemented with Morus alba ad libitum, being hand-milking at 0700 daily. Before analysis, the SCC was logarithmically transformed (log10). Then, PROC Mixed from SAS version 9.4 was used to evaluate all measurements. Regarding our results, the MP had greater milk yields than PM cows (10.83 vs. 9.18 ± 0.38 kg/d; P = 0.003). Similar results were observed for fat-corrected milk (8.26 vs. 6.80 ± 0.34; P = 0.002), although the fat values did not differ between both groups (P = 0.86) being lower than referential values for these breeds (2.46 ± 0.16, on average). No differences were observed in the other milk components (P = 0.65 to 0.85). Despite that, the somatic cell count (SCC) values showed a statistical tendency in PM than in MP (1.89 vs. 2.13 ± 0.05; P = 0.07). In conclusion, low-fat contents were observed in both groups, possibly due to the low quality of foods used in ruminant feeding. While that, the parity and advanced lactation conditioned the SCC contents. Therefore, other studies should be performed to identify more factors that could be determinants. Keywords: Milk, Tropical livestock, Udder health