Twenty Pelibuey×Katahdin ewes (35±2.3 kg) were used to determine the effects of the consumption of standardized plant extract containing a mixture of quaternary benzophenanthridine alkaloids and protopine alkaloids (QBA+PA) on growth performance, dietary energetics, visceral mass, and ruminal epithelial health in heat-stressed ewes fed with a high-energy corn-based diet. The basal diet (13.9% crude protein and 2.09 Mcal of net energy [NE] of maintenance/kg of dry matter) contained 49.7% starch and 15.3% neutral detergent fiber. Source of QBA+PA was Sangrovit RS (SANG) which contains 3 g of quaternary benzophenathridine and protopine alkaloids per kg of product. Treatments consisted of a daily consumption of 0 or 0.5 g SANG/ewe. Ewes were grouped by weight and assigned to 10 pens (5 pens/treatment), with two ewes per pen. The experimental period lasted 70 days. The mean temperature humidity index during the course of this experiment was 81.7±1.0 (severe heat stress). There were no treatment effects on water intake. Dry matter intake was not affected (p = 0.70) by treatments, but the group fed SANG had a numerically (11.2%) higher gain in comparison to the control group, SANG improved gain efficiency (8.3%, p = 0.04), dietary NE (5.2%, p<0.01) and the observed-to-expected NE (5.9%, p<0.01). Supplemental SANG did not affect (p≥0.12) carcass characteristics, chemical composition of shoulder, and organ weights (g/kg empty body weight) of stomach complex, intestines, and heart/lung. Supplemental SANG decreased liver weight (10.3%, p = 0.02) and increased visceral fat (16.9%, p = 0.02). Rumen epithelium of ewes fed SANG had lower scores for cellular dropsical degeneration (2.08 vs 2.34, p = 0.02), parakeratosis (1.30 vs 1.82, p = 0.03) and neutrophil infiltration (2.08 vs 2.86, p = 0.05) than controls. It is concluded that SANG supplementation helped ameliorate the negative effects of severe heat on growth performance of feedlot ewes fed high-energy corn-based diets. Improvement in energetic efficiency may have been mediated, in part, by anti-inflammatory effects of supplemental SANG and corresponding enhancement of nutrient uptake.

One of the main goals of the feedlot industry is to increase efficiency in the final stages of fattening. Therefore, the use of modulators of growth (hormones and beta-agonist agents) is widespread. The concern about the potential impact of the use of these growth promoters has furthered interest in the search for safe alternatives of modulating agents of growth in recent years. In this regards, the use of chelated minerals has shown interesting advantages in nonruminant species. In this sense, chromium (Cr) supplementation, as Cr propionate or Cr methionine, has shown increases in the percentage of carcass muscle and decreased carcass fat in pigs and poultries (1). In ruminants, Cr requirements have not been clearly established (2) and there is limited information available on the effects of Cr on carcass characteristics in feedlot cattle (3) and in feedlot lambs (4). In a recent study (5), linear decreases (P = 0.02) in kidney-pelvicheart fat and fat thickness were observed in finishing steers supplemented with chelated Cr (as Cr-enriched yeast) at daily levels of 0, 5, 10, or 15 mg/head. According to the above study, the maximum response levels were observed when cattle were fed with levels three-fold what is currently recommended. There is limited information regarding the effects of high levels of Cr supplementation on carcass characteristics and chemical composition of muscle of finished lambs. Therefore, the aim of this trial was to evaluate the effects of feeding different levels of chromium methionine on the carcass characteristics and chemical composition of the longissimus muscle (LM) in hairy lambs fed a high-energy diet. Twenty-four Pelibuey × Dorper (initial weight at start of experiment: 24.9 ± 0.2 kg) were assigned (six lambs/treatment) in indoor facilities in collective pens of 16 m 2 with automatic waterers and 1.2 m fence-line feed bunks. Lambs were fed ad libitum with a finishing diet formulated as follows (dry matter basis): 61.2% ground maize, 14.5% soybean meal, 12.6% Sudan grass hay, 7.7% molasses cane, 2.5% mineral premix, and 1.5% zeolite. The calculated composition of the basal diet dry matter basis (6) was as follows: crude protein, 17 g/kg; metabolizable energy, 12.09 MJ/kg; ether extract, 29 g/kg; calcium, 98 g/kg; and phosphorus, 36 g/kg. Lambs were adapted to the basal diet and facilities 14 day Abstract: Twenty-four male lambs (24.93 ± 0.93 kg) were used in order to evaluate the effects of chromium methionine (Cr) supplementation in high-energy finishing diets on the carcass characteristics and chemical composition of the longissimus muscle (LM). Treatments were 0.00, 0.60, 1.20, and 1.80 mg Cr/lamb daily. The experiment lasted 56 days. There were no effects of treatments on dry matter intake, feed to gain ratio, and final weight, which averaged 35.24 ± 1.01 kg. Supplemental Cr linearly decreased fat thickness enough to improve the estimated yield grade from 1.82 to 1.42 with no effect on the other carcass traits measured. Fat concentration in the LM decreased linearly as the lev...