Dietary factors affecting the maximum feed intake and the body composition of pre-ruminant kid goats of the Granadina breed

Body chemical composition and efficiency of energy and nutrient utilization by growing pre-ruminant Saanen goat kids

An experiment involving a feeding trial and a comparative slaughter was conducted to assess the body chemical composition and patterns of nutrient utilization in pre-ruminant Saanen goat kids. Thirty male kids weighing about 6 kg were divided into five equal groups, one of which was slaughtered as the reference group (G0). The remainder were randomly assigned to four feeding levels of 250, 290, 330 and 370 g goats’ milk per kg M0·75 per day and named as groups GI, GII, GIII and GIV, respectively up to about 15 kg live weight, after which they were slaughtered. Mean milk consumption per unit live-weight gain (LWG) (kg/kg), and daily LWG (g/day), for GI, GII, GIII, GIV respectively were: 13·5 and 110; 10·5 and 160; 10·2 and 180; and 10·3 and 200. Empty body weight (EBW) as a proportion of final live weight was 0·95 in the reference animals, and ranged from 0·80 to 0·88 in the treatment groups. The dry matter (DM) concentration in the empty body of kids increased as their age advanced, from 277 g/kg EBW (G0) to between 308 and 326 g/kg EBW (GI to GIV). The protein and fat concentration of LWGs increased with the level of feeding from GI (142 g crude protein (CP) and 75·5 g fat per kg LWG) to GIV (155 g CP and 109 g fat per kg LWG). Regression of energy retention (ER) on metabolizable energy (ME) intake resulted in an efficiency of ME utilization for body retention (k) of 0·72(± 006). ME requirement for maintenance was estimated as 458 kJ/kg M0·75 per day. Efficiency of nitrogen (N) utilization for growth and N requirement for maintenance were estimated as 0·66(±011) and 0·47 g/kg M0·75 per day, respectively.

Growth of Pre-ruminant Kid Goats and the Composition of Carcass Fat Deposits: Effects of Providing a PUFA-rich Fat in the Milk Replacer and Influence of the Kidding Season

The aim of this study is to investigate the possibility of improving the composition of goat meat in terms overall, of the fatty acid composition of different fat deposits. The experiment is designed in an 2 × 2 factorial arrangement. The treatments consist of two different milk replacers, one including and one excluding 2% of fish oil, and two different kidding seasons (spring or autumn). Twelve animals are allocated at random, to each treatment. Animals are slaughtered when they reached a body weight of 7000 ± 200 g. The inclusion of fish oil has no significant effect on growth rate, food efficiency ratio or dressing percentage. The cover, intermuscular and intramuscular fat of the leg from the animals fed with the milk replacer including fish oil, present higher and lower proportions of n-3 PUFA and saturated fatty acids respectively, while that of n-6 PUFA remains unchanged. The inclusion of fish oil in the milk replacer increases the 20 : 5 content in the leg muscle from about 0.4 to 3.5% and 22: 6 content from 0.4 to 2.3%. The fatty acids 20: 5 and 22: 6 are also detected in the cover and intermuscular fat when fish oil is included in the diet. The kid goats born in autumn, show a higher birth weight and growth rate. The leg obtained from these animals, presents a higher proportion of muscle and a lower proportion of bone. However, in the animals born in spring, a somewhat more favourable composition is obtained in the leg fat deposits. The improvement in the quality of meat obtained is discussed, taking into account the feeding strategy provided and the class of animals in question.

Effect of providing a polyunsaturated fatty acid-rich protected fat to lactating goats on growth and body composition of suckling goat kids

The aim of this study was to investigate the possibility of improving the composition of goat meat, in terms of the fatty acid composition of the different fat deposits. For this purpose, we used two groups of 12 female goats each of which had recently undergone a double birth. The animals were maintained under semi-extensive conditions and trough-fed with a concentrate that was either non-supplemented or supplemented with 50 g/kg of polyunsaturated fatty acids (PUFA)-rich fat protected against ruminant metabolism. The kid goats born to each group were suckled by their dams and a representative sample of each was slaughtered at 45 days after birth. The milk produced by the dams receiving the fat-supplemented diet contained fat with a lower content of saturated fatty acids and a higher content of n-3 PUFA, trans-C18: 1 and CLA. The kid goats suckled by these dams grew faster and the legs of the carcasses presented greater muscular development compared with the non-fat-supplemented diet group. The cover, intermuscular and intramuscular fat presented a different fatty acid composition, with a higher proportion of n-3 PUFA, trans C18: 1 and CLA, while that of n-6 PUFA remained unchanged. The change in the lipid metabolism of the kid goats was made evident by the blood levels of certain biochemical parameters. We discuss the improvement in the quality of the meat obtained, taking into account the feeding strategy provided and the class of animal in question.