IMPROVING PRODUCTIVITY OF BARKI GOATS AND THEIR CROSSES WITH DAMASCUS FROM MILK AND KIDS USING FATTY CALCIUM SALTS

Abstract

Recently the importance of goats as a source of meat and milk for human consumption, especially in the developing countries is realized (Devendra 1979). In this respect, the Barki desert goats one subtropical breed of goats have in general low kid production, growth performance, milk production and with few exceptions, of high fertility and moderate prolificacy (Haider 1982). Generally improving goat productivity in subtropical countries was frequently suggested to be achieve by either selection within the native breeds or through crossing with improved exotic breeds (Aboul-Naga et al. 1988 and Abdelaziz et al. 1995).

Goat's milk contains a high proportion of saturated fatty acids, as some what other ruminant milk. Nowadays, pronouncing knowledge showed the risk factor for cardiovascular disease from consuming fatty milk (Ney, 1991). Consequently, attempts have been made to alter composition of milk fat to make it more suitable for human consumption in Egypt and other countries (Grummer, 1991, Ashes et al. 1997, Franklin et a!. 1999 and Youssef 2006).

Fat supplements found the way to be included in the diet of ruminants to increase energy density, improve nutrient utilization, enhance milk and meat yields and manipulate fatty acid composition. (Murphy et al. 1990; Coppock and Wilks, 1991; Ashes et al. 1992; Borsting et a!. 1992; Palmquist et al. 1993 and Scott and Ashes, 1993). Thus, interest of using fats in the rations of farm animals has been increased significantly over the last decade. This interest has been fueled by the acute awareness that the genetic potential for growth and lactation of animals has exceeded their ability to meet their energy need by consuming common feedstuffs.

The most important fats constituents in nutrition include fatty acids, glycerol, mono-di and triglycerids and phospholipids. Fatty acids consist of chains of carbon atoms (2 to 20 or more) and characterized by carboxyle group in one end of carbon chain. Most fatty acids in ruminant tissues are straight chained and have even number or carbons and are esterified to glycerol to form triglycerides.

Ruminant and their associated microbial population evolved with only rather low levels of fat in the feedstuff. Excess fats over 2-3% consider as feed dry inhibitory to microbial activity. Inhibitor effects increase with degree of solubility; so the unsaturated medium-chain and unestrified fatty acids consider to be more inhibitory than estrified as well as the free oils are more inhibitory than those fed in whole seeds (Palmquist, 1984), thus, the fat must be select for use in the rumen. Inert fat (Fatty calcium salts) in simply meaning not affect the microbial fermentation. Moreover, the fatty calcium salts (FCS) is insoluble at normal rumen pH, to be satisfactory stable at 6.5 ruminal pH. In abomasum ; the fatty calcium salts is converted to free fatty acids which are absorbed from the small intestine (Sklan et a!. 1985 and Schneider et al. 1988). In other side, under particular condition, if the ruminal pH is less than 6, a relatively high dissociation of ca-salts followed by the hie-hydrogenation of long-chain unsaturated fatty acids. The resistance of ca-salts to dissociation and hie-hydrogenation may also depend on the degree of fatty acids unsaturation (Sukhija and Palmquist, 1990). Ruminally inert fats have been developed to