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

Tripti Sharma,Joydip Mukherjee,Pradip Kumar Das,Dipak Banerjee,Prabal Ranjan Ghosh

doi:10.14202/vetworld.2017.342-347

Abstract

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.

Highlights

Defense of the mammary gland against mastitis-causing pathogens is mediated by several anatomical, cellular, and soluble protective factors together with other physiological and managemental factors including breed, parity, period of lactation, udder and teat morphology, age at first calving, milk leakage, udder edema, milk production, number of milk somatic cell counts (SCC), reproductive disorders, and preventive health management [1,2]
Table-1 describes the correlation between udder morphology with milk SCC, differential leukocyte counts (DLC) and in vitro activity of milk leukocytes
There was no significant correlation between milk DLC and teat morphology

Summary

Introduction

Defense of the mammary gland against mastitis-causing pathogens is mediated by several anatomical, cellular, and soluble protective factors together with other physiological and managemental factors including breed, parity, period of lactation, udder and teat morphology, age at first calving, milk leakage, udder edema, milk production, number of milk somatic cell counts (SCC), reproductive disorders, and preventive health management [1,2]. The cellular defenses include milk SCC comprising leukocytes (neutrophils, lymphocytes, and macrophages) together with epithelial cells and play a key role in the natural defense mechanism of the udder and in vitro. Activity of milk leukocytes can be used to monitor the udder health [3,4,5]. Scanty references are available elucidating the association between the udder morphology with udder immunity, especially the activity of mammary leukocyte

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