Feeding Management Strategies to Mitigate Methane and Improve Production Efficiency in Feedlot Cattle

Mitigation of greenhouse gases and decreasing nutrient excretion have become increasingly important goals for the beef cattle industry. Because feed intake is a major driver of enteric CH₄ production and nutrient excretion, feeding management systems could be important mitigation tools. Programmed feeding uses net energy equations to determine the feed required to yield a specific rate of gain, whereas restricted feeding typically involves decreasing intake relative to the expected or observed ad libitum intake. In the context of growing/finishing systems typical of those in the United States and Western Canada, experimental results with programmed and restricted feeding have often shown decreased overall feed intake and increased gain efficiency relative to ad libitum feeding, but too much restriction can negatively affect harvest weight and associated carcass quality. Slick feed bunk management is a time-based restriction that limits day-to-day variation in feed deliveries, but the effects on intake and performance are not well defined. Simulations to estimate enteric CH₄ emission and nitrogen excretion indicated that programmed feeding of a high-grain diet could appreciably decrease CH₄ emissions and nitrogen excretion compared with traditional growing programs based on high-forage diets. For feedlot finishing, programming gain for a portion of the feeding period will decrease CH₄ emission and N excretion only if cattle perform better than expected during the programmed phase or if compensatory growth occurs when cattle are transitioned to ad libitum feeding. Optimal approaches to implement programmed or restricted feeding that will yield increased efficiency should be the subject of future research in this area.

Viability of the use of mycotoxin adsorbent in the finishing of Texel lambs in confinement

The objective of the present study was to evaluate the viability of a mycotoxin adsorbent based on beta-glucans from cell walls of Saccharomyces cerevisiae and bentonites in the diets of confined lambs of the Texel breed. Twenty-four lambs (12 males and 12 females) with an average weight of 18.6 kg ± 1.6 were divided into two groups: treated (with adsorbent) and control. The animal diets contained the mycotoxins aflatoxin B1, fumonisin B1 and B2, zearalenone, and deoxynivalenol in concentrations within guidance levels. The animals were slaughtered with body weight of approximately 26.4 kg. The performance and carcass variables of the lambs were evaluated. The daily weight gain was higher in the treated group (216.24 g) than in the control group (185.90 g). The averages for loin eye area, subcutaneous fat thickness, and marbling were 13.93 cm², 2.66 mm, and 3.20 in the treated group and 12.16 cm², 2.6 mm, and 3.25 in the control group, respectively. The true, hot, and cold carcass yield, and the carcass cooling losses did not differ between groups. The carcasses were similar in conformation and fat finishing degree, with averages of 3.95 and 3.83, respectively. To the best of our knowledge, this is the first study to evaluate the effect of a mycotoxin additive in the diet of finishing lambs. The use of mycotoxin adsorbent in confined lambs was feasible, and its use resulted in greater daily weight gain in lambs and average net profit.

Effect of restricted-feeding strategies on blood concentrations of hormones, metabolites, and minerals in Holstein × Zebu finishing steers

Abstract The objectives were to determine the effects of restricted-feeding strategies on blood concentrations of hormones, metabolites, and minerals in Holstein × Zebu finishing steers. Twenty steers (body weight = 319 ± 16.2 kg; age = 19 ± 1 months) were randomly allotted in 4 groups of 5 steers, which were restricted to 85% ad libitum feed intake for either 0 (R0; n = 5), 28 (R28; n = 5), 42 (R42; n = 5) or 84 (R84; n = 5) days of an 84-d finishing period. Steers were individually housed and considered the experimental unit. Blood samples were collected on d 0, 21, 42, 63, and 84, and were assayed for insulin-like growth factor 1 (IGF-1), thyroid hormones (T3 and T4), albumin, creatinine, urea, total protein, glucose, triglycerides, calcium, and phosphorus. Steers had increasing IGF-1 concentrations until d 42 when restricted-fed. Steers fed R84 had the greatest IGF-1 concentrations on d 84. Urea concentrations were greatest in steers fed R0 and least in steers fed R28; steers fed R42 and R84 were intermediate and not different from one another. Concentrations of IGF-1, urea, albumin, and calcium, but not T3, T4, glucose, triglycerides, creatinine, total protein, and phosphorus were affected by restricted-feeding strategies in Holstein × Zebu finishing steers.