Seasonal variation inin vitroimmune activity of milk leukocytes in elite and non-elite crossbred cows of Indian sub-tropical semi-arid climate

Quantitative Associations between Season, Month, and Temperature-Humidity Index with Milk Yield, Composition, Somatic Cell Counts, and Microbial Load: A Comprehensive Study across Ten Dairy Farms over an Annual Cycle

This current study addresses the knowledge gap regarding the influence of seasons, months, and THI on milk yield, composition, somatic cell counts (SCC), and total bacterial counts (TBC) of dairy farms in northeastern regions of Iran. For this purpose, ten dairy herds were randomly chosen, and daily milk production records were obtained. Milk samples were systematically collected from individual herds upon delivery to the dairy processing facility for subsequent analysis, including fat, protein, solids-not-fat (SNF), pH, SCC, and TBC. The effects of seasons, months, and THI on milk yield, composition, SCC, and TBC were assessed using an analysis of variance. To account for these effects, a mixed-effects model was utilized with a restricted maximum likelihood approach, treating month and THI as fixed factors. Our investigation revealed noteworthy correlations between key milk parameters and seasonal, monthly, and THI variations. Winter showed the highest milk yield, fat, protein, SNF, and pH (p < 0.01), whereas both SCC and TBC reached their lowest values in winter (p < 0.01). The highest values for milk yield, fat, and pH were recorded in January (p < 0.01), while the highest protein and SNF levels were observed in March (p < 0.01). December marked the lowest SCC and TBC values (p < 0.01). Across the THI spectrum, spanning from -3.6 to 37.7, distinct trends were evident. Quadratic regression models accounted for 34.59%, 21.33%, 4.78%, 20.22%, 1.34%, 15.42%, and 13.16% of the variance in milk yield, fat, protein, SNF, pH, SCC, and TBC, respectively. In conclusion, our findings underscore the significant impact of THI on milk production, composition, SCC, and TBC, offering valuable insights for dairy management strategies. In the face of persistent challenges posed by climate change, these results provide crucial guidance for enhancing production efficiency and upholding milk quality standards.

Milk production status and associated factors among indigenous dairy cows in Raya Kobo district, north eastern Ethiopia

Background

Result

Conclusion

Association between udder morphology and in vitro activity of milk leukocytes in high yielding crossbred cows

Aim:

The present investigation was conducted to study the association between udder morphology and in vitro activity of milk leukocytes in high yielding crossbred cows.

Materials and Methods:

A total of 48 healthy high yielding crossbred cows were selected for the study. The udder configuration and teat/udder morphology were recorded before milking. Milk samples (100 ml/cow) were collected aseptically. Milk somatic cell counts (SCC) and milk differential leukocyte counts were performed microscopically. Milk leukocytes (viz., neutrophils, lymphocytes, and macrophages) were isolated from milk samples by density gradient centrifugation. Phagocytic index (PI) of milk neutrophils and macrophages were evaluated by colorimetric nitro blue tetrazolium assay. Lymphocytes proliferation response was estimated by MTT assay and expressed as stimulation index.

Results:

There was a significant (p<0.01) positive correlation between milk SCC with mid teat diameter, teat base diameter and significant (p<0.05) negative correlation between milk SCC and the height of the teat from the ground. Milk SCC was found to be significantly (p<0.01) lower in bowl-shaped udder and higher (p<0.01) in pendulous type. Milk macrophage percentage was positively (p<0.01) correlated with udder circumference. PI of milk neutrophil was negatively (p<0.01) correlation between teat base diameter, and PI of milk macrophages was found to be positively (p<0.01) correlated with teat apex diameter. Both PI of milk neutrophils and macrophages was found to be significantly (p<0.01) lower in the animals having flat and round teat and pendulous type of udder. In vitro PI of milk neutrophils was found to be significantly (p<0.01) lower in flat teat. In vitro PI of milk macrophages was found to be significantly (p<0.01) lower in the round and flat teats compared to pointed and cylindrical teats.

Conclusion:

Udder risk factors such as teat shape and size, teat to floor distance, udder shape, and size may decrease the in vitro activity of milk leukocytes hence facilitates the incidence intramammary infections.