Evaluation of Kenya Alpine Dairy Goat (Capra aegagrus hircus) Milk Yield, Nutritional and Chemical Composition and Product Development

Abstract

In Kenya use of exotic dairy goats in breeding programmes for smallholder production systems has become popular, but there is lack of information on the milk yield and nutritional quality as well as milk value addition. The aim of this study was to investigate the milk potential of Kenya Alpine dairy goats reared in Mukurweini as a high potential region, and Kieni East and Kieni We~L as semi-arid regions, of Nyeri County, evaluate the nutritional and chemical composition of the milk from pedigree grade in the three regions, and develop Paneer cheese and yoghurt from milk of the pedigree grade in Mukurweini region. A descriptive survey method was used to assess the effect of grade and age of the doe on milk yield in the three geographical areas. Randomized complete block design was used to assess milk nutritional and chemical composition, with each region being treated as a block. Using a completely randomized design, ten pedigree dairy goats were identified in Mukurweini region, where randomization was achieved by collecting milk samples from each farm in triplicates over a period of three months. General Linear Model Univariate procedure revealed that the appendix grade in Kieni East significantly (p<O.OS) produced highest milk yield per day, 2.69 litres/day. Crossbreeding the local goat with exotic alpine buck led to significant (p<O.OS) increase in daily milk production within Kieni West, from the original (1.00 litre/day) to pedigree grade (2.1S litres/day). The dairy goats start to produce milk at the age of2.0 to 2.9 years, with milk yield showing significant (p<O.OS) variation in different age groups. There was a significant (p<O.OS) increase in milk yield for the pedigree grade at the age of s.o and S.9 years, in the three regions of study. Goat milk from Mukurweini had significantly (p<O.OS) higher amount of ash (O.96g1100ml), fat (4.01 gl100ml) and protein (4.58 gllOOml) as compared to the other two regions of the semi-arid area. The mineral composition differed clearly among the three regions with Mukurweini giving significant(p<O.OS) high amounts of calcium 152.61 mgl100ml, magnesium 19.90 mgl100ml, iron 0.84 mg/lOOml, zinc 0.57 mg/100ml, 'sodium SI.04 mgllOOml and potassium 196.65 mgl100ml. Dairy goat milk from Mukurweini region also had significant (p<0.05) high levels of methionine 2.84 g/I Oug protein, phenylalanine 5.56 gl100g protein, threonine 4.79 gl100g protein, histidine 3.61 g/100g protein and leucinelO.73 gl100g protein. Paneer cheese developed from cow milk was significantly (p<O.OS) preferred in taste over goat milk Paneer cheese, due to its high fat content. However the white colour of the goat milk Paneer cheese was preferred over the cream colour of cow Paneer cheese. Goat milk yoghurt with modified com starch (0.2g11 of milk) scored the highest overall acceptability on a S-point hedonic scale, while goat natural yoghurt rated poorly in consistency. The study established that the Kenya alpine dairy goat milk yield is affected.by grade and age of the doe, while geographical location of the dairy goat rearing affects both the milk yield and nutritional composition. Yoghurt with starch, 0.2g1litre of milk, was preferred over cow milk yoghurt. There is need for further research to assess the effect of feed type and stage of lactation on goat milk yield and quality, goat milk cheese development coupled with consumer studies, and shelf stability of both yoghurt and cheese products.