Evaluation Of Kenya Alpine Dairy Goat (Capra Aegagrus Hircus) Milk Yield, And Its Nutritional And Chemical Composition For Product Development, In Nyeri County

ABSTRACT

In Kenya use of exotic dairy goats in breeding programmes for smallholder production systems has become popular, but information on the milk production and nutritional quality is scarce. This research project was done to investigate the milk yield and its nutritional composition of Kenya Alpine dairy goat, Capra aegagrus hircus, for value addition. The initial work constituted assessing the dairy goat feeding practices in the study areas of Mukurweini, Kieni East and Kieni West, where it was found that all the households involved in the study relied on natural pastures as a source of feed for dairy goats. The dairy goats in Kieni East and Kieni West were fed with concentrates and mineral supplementation during milking, while Mukurweini farmers used less concentrates and no mineral supplements. The Appendix grade in Kieni East gave the highest amount of milk per day, while the foundation grade in Mukurweini produced the least. There was significant increase in daily milk production with crossbreeding in Kieni West, from the original to pedigree grade. Consequently, there was no improvement in daily milk production with the crossbred goats in the Kieni East and Mukurweini. The dairy goats start to produce milk at the age of 2.0 to 2.9 years in the three regions, with milk yield showing significant variation in different age groups. There was a significant increase in milk production for the pedigree grade at the age of 5.0 and 5.9 years. Variations were noted in milk chemical composition for dairy goats in semi arid and high potential areas under the study. Mukurweini dairy goat milk had higher amount of ash, fat and protein as compared to the other two regions of the semi arid area. The mineral composition differed clearly among the three regions with Mukurweini giving significantly higher amounts of calcium, magnesium, iron, zinc, sodium and potassium In the semi arid areas of Kieni East and West, dairy goat easily adapt to the harsh climate and scarcity of fodder while in Mukurweini there are readily available fodders to feed the dairy goats, thus the high mineral components. Significant low levels of niacin and riboflavin were noted in Kieni west, while Mukurweini region gave high amounts of riboflavin and αtocopherol as compared to the other two regions. In the high potential areas of Mukurweini the milk was significantly higher in palmitic and stearic acids, and low amounts of lauric acid. Mukurweini region also had significant High levels of methionine, phenylalanine, threonine, histidine and leucine were obtained from goat milk at Mukurweini region. The significant amounts of essential amino acids in milk protein were due to the high nitrogenous fodder given to the dairy goats in this region. Goat and cow milk Paneer cheese chemical composition, showed significant difference in fat content. There was a significant liking for cow milk Paneer cheese as compared to the goat milk Paneer cheese, in terms of taste and aftertaste, where cow paneer had creamy milky taste and nutty after taste, as compared to that of goat milk which had slightly bitter/sour taste. A smooth texture/appearance was characteristic of the two cheese samples while the cream of cow milk cheese and pure white colour of the goat milk cheese were both acceptable to the panelists. A reduction of the scores for body and texture was observed in both goat milk and cow milk natural yogurt. Among all analyzed types, the goat milk yoghurt with 2% starch revealed the highest overall acceptability, while natural yoghurt from goat milk scored the lowest overall acceptability. A higher score for goaty flavor in goat milk yogurt fortified with 2% starch and vanilla flavored was observed indicating a higher acceptability for the flavor of the new product. Analyzed results for odor showed a high score for all types of yogurt indicating that the goat milk yoghurt did not produce an off odour, as is perceived culturally. The study established that the geographical location of the dairy goat rearing affect both the quality and quantity of milk produced, which is also dependant on the type of fodder available in that region, feeding practices, age of the dam and the grade.