Effects of Replacing Cottonseed Meal with Corn Dried Distillers’ Grain on Ruminal Parameters, Performance, and Enteric Methane Emissions in Young Nellore Bulls Reared in Tropical Pastures

Two experiments were conducted to evaluate the effect of replacing cottonseed meal with DDG on ruminal parameters, methane (CH4) emissions (Experiment 1), and animal performance (Experiment 2) of young Nellore bulls grazing Marandu grass during the rainy season. Four supplementation strategies were used in both experiments: (1) Mineral supplementation (MS); (2) conventional multiple supplement (energy/protein) with cottonseed meal and citrus pulp (CMS); (3) CMS with 50% cottonseed meal replaced by DDG (50DDG); and (4) CMS with 100% cottonseed meal replaced by DDG (100DDG). The 50DDG condition resulted in greater intake of dry matter (p = 0.033), organic matter (OM) (p = 0.050), forage (p = 0.035), and digestible OM (p = 0.031) than 100DDG. The supplemented animals presented greater final body weight (BW) and average daily gain than the animals consuming MS (p = 0.011), and lower pH, acetate, and acetate:propionate (p < 0.05). However, the treatments had no influence on stocking rate, gain per area, and enteric CH4 emissions (p > 0.05). Replacing cottonseed meal with DDG does not result in great variations in ruminal parameters, animal performance, and enteric CH4 emissions of grazing Nellore cattle during the rearing phase in the wet season. Both protein sources in 0.3% BW supplementation can be used to intensify beef cattle production in pastures.

PSXIII-3 Effects of mineral source and additive in mineral supplementation on productive performance of growing beef cattle on tropical pastures

Our objective was to evaluate the effects of mineral supplementation using the association of carboaminophosphochelates as mineral source plus Salinomycin on grazing beef cattle performance during growing phase. A total of 80 Nellore bulls (IBW = 292.72 ± 13.55 kg; Age, ~13 mo) were distributed in 8 paddocks (~2.7 hectares each) planted with Palisade Grass cv. Xaraés during the rainy to rainy-to-dry transition seasons (February to May). The experiment was a randomized complete block design (10 animals/paddock, 4 paddocks per treatment). The mineral supplementation was provided ad libitum and treatments were: Control; Mineral supplementation containing inorganic minerals, and TM+Salinomycin = Mineral supplementation containing carboaminophosphochelates (TM, Tortuga® Minerals) as minerals source (Cr, Se, Zn, Mn, S, Cu e Co) plus Salinomycin (~108 mg per animal/day). The supplement orts were removed and weighted daily to calculate supplement intake. The animals were weighed after a 14 h-fasting at the beginnig and end of the trial (84 days) to calculate weight gain. The paddock was considered the experimental unit and data were analyzed using PROC MIXED of SAS, whereby means were separated using the PDIFF statement (P &lt; 0.05). Supplement intake was similar between treatments (P = 0.13). Animals supplemented with TM+Salinomycin tended to have greater final BW (358 vs. 347, P = 0.07) and increased ADG in 22,3% (0.730 vs. 0.597 kg/d, P = 0.03) compared with animals fed Control. In conclusion, the combination of carboaminophosphochelates minerals plus salynomicin improves grazing beef cattle weight gain, with no deleterious effect on mineral supplement intake.

Prediction of Carcass Traits of Santa Inês Lambs Finished in Tropical Pastures through Biometric Measurements

The aim of this study was to predict carcass traits of Santa Inês lambs finished in tropical pastures by using biometric measurements. Data originated from two experiments involving 56 lambs (32 in experiment I and 24 in experiment II). In both experiments, the sheep were finished in that were finished in pastures of Panicum maximum and Brachiaria brizantha, experiment I being conducted in the rainy season and experiment II in the dry season. The following biometric measurements were recorded before slaughter: body length (BL), withers height (WH), rump height (RH), thorax width (TW), rump width (RW), chest width (CW), heart girth (HG), thigh circumference (TC), rump circumference (RC) and leg length (LL), in addition to live weight at slaughter (SW). After slaughter, hot carcass weight (HCW), cold carcass weight (CCW) and the weights of primal cuts (shoulder, neck, loin, leg and rib) were recorded. In the equations generated to predict SW, HCW and CCW, R2 ranged from 0.58 to 0.91 and the measurements of WH, TC, CW, HG and RW were the most relevant. In the equations developed to predict the weight of primal cuts, in turn, R2 ranged from 0.26 to 0.99. In these models, SW, BL, CW, TC, LL and HG explained most of the variation in the weight of primal cuts. Biometric measurements can be used to accurately and precisely predict HCW, CCW and the weight of primal cuts from the carcass of Santa Inês sheep finished in tropical pastures, since the equations presented R2 and correlation coefficient and agreement above 0.8.

Soil Carbon Storage Potential of Tropical Grasses: A Review

Environmental degradation and climate change are key current threats to world agriculture and food security and human–induced changes have been significant driving forces of this global environmental change. An important component is land degradation which results in a diminished soil organic carbon (SOC) stock with concomitant loss of soil condition and function. Land management to improve soil organic matter content, condition and productivity is therefore a key strategy to safeguard agricultural production, food supply and environmental quality. Soil organic carbon sequestration through the use of plant species with high photosynthetic efficiency, deep roots and high biomass production is one important strategy to achieve this. Tropical pastures, which are adapted to a wide range of environmental conditions have particular potential in this regard and have been used extensively for land rehabilitation. Tropical pastures also have advantages over trees for biomass and carbon accumulation due to their rapid establishment, suitability for annual harvest, continual and rapid growth rates. In addition, tropical pastures have the potential for SOC storage in subsoil horizons due to their deep root systems and can be used as biomass energy crops, which could further promote their use as a climate change mitigation option. Here we aimed to review current knowledge regarding the SOC storage potential of tropical grasses worldwide and identified knowledge gaps and current research needs for the use of tropical grasses in agricultural production system.