Meat yield and quality of Tanzania Shorthorn Zebu cattle finished on molasses/maize grain with agro-processing by-products in 90 days feedlot period

This study was conducted to evaluate the effects of feeding molasses or maize grain with agro-processing by-products on yield and quality of meat from Tanzania shorthorn zebu (TSZ) cattle. Forty five steers aged 2.5 to 3.0 years with 200 +/- 5.4 kg body weight were allocated into five dietary treatments namely hominy feed with molasses (HFMO), rice polishing with molasses (RPMO), hominy feed with maize meal (HFMM), rice polishing with maize meal (RPMM) and maize meal with molasses (MMMO). Ad libitum amount of each dietary treatment and hay were offered to nine steers for 90 days. Cooking loss (CL) and Warner Bratzler shear force (WBSF) values were determined on M. longissimus thoracis et lumborum aged for 3, 6, 9 and 12 days. Steers fed on HFMO diet had higher (P < 0.05) nutrient intake (86.39 MJ/d energy; 867 g/d CP), weight gain (919 g/d) and half carcass weight (75.8 kg) than those fed other diets. Meat of steers from all diets was tender with average WBSF values of 47.9 N cm^(−2). The CL (22.0 +/- 0.61%) and WBSF (53.4 +/- 0.70 N cm^(−2)) were highest in meat aged for 3 days followed by 6, 9 and 12 days. WBSF values for meat aged for 9 and 12 days from steers fed HFMO and RPMM diets were similar and lower than those on other dietary treatments x aging periods. Overall, molasses and hominy feed can be used to replace maize meal in feedlot finishing diets to spare its use in animal feeds.

Potential mitigation of midwest grass-finished beef production emissions with soil carbon sequestration in the United States of America

Beef production can be environmentally detrimental due in large part to associated enteric methane (CH4) production, which contributes to climate change. However, beef production in well-managed grazing systems can aid in soil carbon sequestration (SCS), which is often ignored when assessing beef production impacts on climate change. To estimate the carbon footprint and climate change mitigation potential of upper Midwest grass-finished beef production systems, we conducted a partial life cycle assessment (LCA) comparing two grazing management strategies: 1) a non-irrigated, lightly-stocked (1.0 AU/ha), high-density (100,000 kg LW/ha) system (MOB) and 2) an irrigated, heavily-stocked (2.5 AU/ha), low-density (30,000 kg LW/ha) system (IRG). In each system, April-born steers were weaned in November, winter-backgrounded for 6 months and grazed until their endpoint the following November, with average slaughter age of 19 months and a 295 kg hot carcass weight. As the basis for the LCA, we used two years of data from Lake City Research Center, Lake City, MI. We included greenhouse gas (GHG) emissions associated with enteric CH4, soil N2O and CH4 fluxes, alfalfa and mineral supplementation, and farm energy use. We also generated results from the LCA using the enteric emissions equations of the Intergovernmental Panel on Climate Change (IPCC). We evaluated a range of potential rates of soil carbon (C) loss or gain of up to 3 Mg C ha-1 yr-1. Enteric CH4 had the largest impact on total emissions, but this varied by grazing system. Enteric CH4 composed 62 and 66% of emissions for IRG and MOB, respectively, on a land basis. Both MOB and IRG were net GHG sources when SCS was not considered. Our partial LCA indicated that when SCS potential was included, each grazing strategy could be an overall sink. Sensitivity analyses indicated that soil in the MOB and IRG systems would need to sequester 1 and 2 Mg C ha-1 yr-1 for a net zero GHG footprint, respectively. IPCC model estimates for enteric CH4 were similar to field estimates for the MOB system, but were higher for the IRG system, suggesting that 0.62 Mg C ha-1 yr-1 greater SCS would be needed to offset the animal emissions in this case.