Relationship of somatic cell count, physical, chemical and enzymatic properties to the bacterial standard plate count in dairy goat milk
Journal
Livestock Production Science
Journal Volume
74
Journal Issue
1
Date Issued
2002-02-13
Author(s)
Abstract
Weekly milk samples, collected from individual half mammary gland of three late lactation (experiment 1) and four early lactation (experiment 2) Alpine dairy goats in second lactation, were subjected to various physical and chemical measurements to examine the relationship of the logarithm of bacterial standard plate count (SPC) to electrical conductivity (EC), neutrophils/lymphocytes ratio, lactate dehydrogenase (LDH), tyrosine concentration, alkaline phosphatase (ALP), the logarithm of somatic cell count (SCC) and various milk constituents (fat, protein, lactose, K+, Na+, Cl-, P). Tank milk samples (experiment 3), obtained twice a month from 20 commercial farms for a period of 3 months, were also subjected to the same measurements and analysis. The measured SCC of the present study ranged from 0.137 to 8.043 × 106/ml. The measured SPC ranged from 0 to 7.76 × 106/ml. Both of the SCC and the SPC showed a wide distribution allowing a better opportunity to examine the correlation analysis of other measured parameters with SCC or SPC. The results showed that the logarithm of SCC did not have a significant correlation with the logarithm of SPC for late lactation and commercial tank milk samples. The best-fit analysis also showed a different pattern of regression equations for the logarithm of SPC and SCC, indicating that SCC and SPC were not equally interchangeable parameters as indicators of mammary gland infection for Alpine goats or commercial goats of mixed breeds. There was negative correlation between the logarithm of SPC and lactose content in the early lactation and the commercial farms' tank milk samples, but not the late lactation milk samples. The logarithm of SCC was negatively correlated to the milk yield (P < 0.01), and positively to EC (P < 0.05) for both early and late lactation milk samples. Milk protein content consistently showed a significant (P < 0.01) positive correlation to the logarithm of SCC across all three experiments. The present study did showed a similar correlation between SCC and milk yield, EC or milk protein content of dairy goats' milk as found in dairy cows' milk. However, the present study showed that the possibility of employing commonly used physiological parameters for dairy cows was unsuitable in evaluating the mammary health status of dairy goats. © 2002 Elsevier Science B.V. All rights reserved.
Subjects
Alkaline phosphatase; Chloride; Electrical conductivity; Goat milk; Lactate dehydrogenase; Potassium; Sodium; Somatic cell count; Standard plate count; Tyrosine
Type
journal article