Document Type : Original Article
Authors
1
Sheep & Goat Research Department, Animal Production Research Institute, Ministry of Agriculture and Land Reclamation, Dokki,. Giza, Egypt.
2
Dairy Microbiology Research Department, Animal Production Research Institute, Ministry of Agriculture and Land Reclamation, Dokki,. Giza, Egypt.
3
Biotechnology Research Department, Animal Production Research Institute, Ministry of Agriculture and Land Reclamation, Dokki,. Giza, Egypt.
Abstract
ABSTRACT
This study aimed to investigate the relationship between SCC, milk yield and composition in Damascus goats in Egypt, as well as, to evaluate the validity of using SCC for monitoring early udder infection.
A total of 204 milk samples were collected at mid lactation (June 2013) from both halves of udders of 51 Damascus goats. Milk bacteriological examination was performed using all half milk samples of morning milking, while percentage of fat (F), total protein (P), lactose (L), total solid (TS), solid not fat (SNF) and SCC were estimated in all collected samples of morning and evening milking. In the present study, 68.3% of the udder half were bacteriologically free of mastitis (healthy), while 31.7% was infected. Seven types of microorganisms were isolated from the milk of Damascus goats. Intermammary infection (IMI) was categorized as 1- healthy (68.3%), 2- infected with single major pathogen (10.9%), 3- infected with single minor pathogen (7.9%), 4- infected with double major pathogens (2.97%), 5- infected with double minor pathogens (0.99%) and 6- infected with one major pathogen plus one minor pathogen (8.9%).
Milk yield was significantly higher in healthy than in infected goats, while insignificant changes were recorded on the percentage of protein, fat, lactose, total solid, solid not fat and SCC. Meanwhile, a negative insignificant correlation was detected between milk yield and SCC. Results showed that the highest milk yield was recorded in the 5th parity, while the lowest observed in the 1st parity. Moreover, percentages of protein, total solids and solids not fat were significantly higher for Damascus goats in the 2nd parity than other parities, with a parallel, but insignificant, increase in fat content. High SCC scores combine with alteration in milk composition, where protein and solid not fat percentage increased and lactose percentage decreased with the increase of SCC in milk (log SCC ranged from 6.51 to 7.25). Although, a threshold of 1,000,000 cells /ml showed the best indication for IMI, this study showed that high SCC does not always reflect mastitis probably due to the apocrine secretion in goats. Animals with elevated SCC should declare positive mastitis after successful isolation and identification of bacteria causing mastitis. Nevertheless, in case of suspected udder infection, SCC in goat' milk could be suitable as early and cost-effective screening parameter till initiate further analysis.
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