Browsing by Author "Yeshimebet, Chanyalew"

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    Study of the Effects of Sub Clinical Mastitis and Other Production Factors on Cow Milk Fat and Protein Concentration in and Around Gondar Northwestern Ethiopia
    (2007-06) Yeshimebet, Chanyalew; Dr. Mekonen H/Mariam, Dr. Girma Zewde
    The impact of sub clinical mastitis and other production factors on cow milk protein and fat concentrations in dairy cows were studied from October 2006 to June 2007 in and around Gondar. By way of cross sectional survey data were collected from 236 milking cows of 105 smallholder dairy farmers. Instruments used for data collection were questionnaire survey, farm inspection, animal examination and laboratory analysis. Descriptive statistics, linear regression and correlation coefficients between variable were computed. Mastitis prevalence at herd and cow levels was respectively 37.1% and 33.1%. From the total mastitis cases 2.6% was clinical and the rest 30.5% sub clinical mastitis. Sub clinical mastitis reduced milk fat and protein concentrations by 15.4% and 8.2% respectively; the differences were statistically significant (P<0.05). The influence of three other factors, namely breed, feed and management, on fat and protein concentrations were also examined both in mastitic and healthy cows. Breed effect was significant for fat ((P=0.031) and protein (P=0.024). Indigenous breeds had higher fat and protein concentrations compared to 50% and above crosses. The effect of sub clinical mastitis was found more pronounced in 50% crosses. Cows fed on, relatively, low quality feeding stuffs (grazing with very minimum supplementation) had significantly low level of fat (P=0.008) and protein (P=0.05). In poorly fed cows, the effect of sub clinical mastitis in modifying milk composition concentrations was quite high. Management was also very much related to milk composition. Improved management significantly increased fat (P=0.004) and protein (P=0.012) concentration. Mastitic cows subjected to poor management had more depressed fat and protein levels. V The regression analysis made after grouping milking cows by breed allowed the fitting of mathematical models that estimated, with good precision, fat and protein concentrations in healthy and mastitic cows.