Pedro A. Hernández-García

Effects of dietary calcium propionate on growth performance and carcass characteristics of finishing lambs

The objective of this study was to evaluate the effects of the addition of two levels of calcium propionate on lamb performance and some carcass characteristics. Twenty-one male Creole lambs with an initial weight of 25.3 ± 3.3 kg were randomly assigned to one of the following treatments: 0, 10, and 20 g of calcium propionate/kg of diet (dry matter basis). Intake, daily gain, feed conversion, carcass weight, and rib eye area were not affected (P < 0.05) by calcium propionate addition. Ruminal fermentation was not altered (rumen pH, volatile fatty acids concentration, and fermentation pattern), and ruminal ammonia-N presented a quadratic response (P < 0.05). In fat from the longissimus dorsi muscle, oleic acid showed a linear decrease (P < 0.05) and α-linolenic presented a linear increment (P < 0.05). The addition of 10 or 20 g of calcium propionate in diets containing 350 g/kg grain and 100 g/kg molasses did not modify the productive performance of lambs or ruminal fermentation, and minor changes were detected in long-chain fatty acid in intramuscular fat.

Effects of feeding yeast(Saccharomyces cerevisiae), organic selenium and chromium mixed on growth performance and carcass traits of hair lambs

Abstract Yeasts and organic minerals are used in diets to improve health, productive performance and some carcass characteristics of ruminants and non-ruminants. Thirty-two lambs (Pelibuey×Katahdin; BW=(30.55±1.67) kg; n =8) were used in a 56-d feeding experiment to study the effects of different levels of live yeast ( Saccharomyces cerevisiae ; yeast), selenium (Se) and chromium (Cr) mixed (Se-Cr), and a mixture of yeast-Se-Cr on growth performance and carcass traits. Animals were stratified by body weight (BW) and randomly assigned to one of four treatments: 1) control group (0.0 g kg −1 yeast); 2) yeast (1.50 g kg −1 dry matter intake (DMI) d −1 ); 3) Se-Cr premix (1.5 mg kg −1 DMI d −1 for each mineral); and 4) yeast-Se-Cr mixture. There were no treatment effects on final BW; whereas lambs fed Se-Cr or yeast-Se-Cr had higher ( P P >0.05) among treatment groups. In conclusion, supplementation with yeast, Se-Cr mixed or yeast-Se-Cr did not improve ADG, final BW, back fat content and carcass yield of growing of Pelibuey×Katahdin lambs. Supplementation with Se-Cr and yeast-Se-Cr increased DMI, and approximately 250 g ADG animal −1 d −1 was produced with no negative effects on growth and health of the animals.