Composition of ewe, goat and cow milk and of colostrum of ewes and goats

Abstract

Colostral samples were taken immediately after confinement from 16 Chios ewes and 12 Damascus goats for determination of fat, crude protein (CP), lactose, ash and total solids (TS). Milk samples from sheep ( n = 432), goats ( n = 721) and cows ( n = 861) representative of all stages of lactation were also taken, over the period 1983 to 1988. These were analyzed for fat, CP, ash and TS. Milk samples from 30 ewes, 30 goats and 44 cows were taken for fat, ash, TS, total CP and non-protein nitrogen (NPN) determination. Highest correlation in all three species was obtained from the multiple regression of TS ( Y) on fat ( X 1) and CP ( X 2). The correlation between fat and TS was lower in ewe ( R 2 = 0.41) than cow ( R 2 = 0.70) and goat ( R 2 = 0.71) milk. With the exception of ewes ( R 2 = 0.68), correlation between CP and TS was low in cow ( R 2 = 0.28) and goat ( R 2 = 0.24) milk. Ewe milk had the highest fat, CP, ash and TS content followed by goat milk; cow milk having the lowest. Goat milk had the highest NPN (2.91 g kg −1), ewe milk being intermediate (2.7 g kg −1) and cow milk the lowest (2.18 g kg −1). NPN as percent of total CP was similar in goats (7.13%) and cows (7.43%), but lower in ewes (4.66%). Lactose content of colostral milk was low in the first sampling (Day 1), increased sharply in the second, and steadily later on. The difference between ewes and goats in their colostral lactose was small compared with other constituents. TS, CP, ash and fat contents were higher on Day 1 and fell thereafter. It is concluded that there are differences in normal milk composition among ewes, goats and cows which may affect their performance for cheese manufacturing, and that from TS determination fat and CP (CP in ewes only) can be estimated with relatively high precision. Existing differences in colostral milk between ewes and goats should be taken into consideration when giving colostrum to offspring of the two species.