Carcass traits and meat characteristics of grazing Nellore cattle submitted to different supplementation strategies in the tropics.

This study explored the effects of different supplementation strategies during the dry and rainy seasons in the tropics on the carcass traits and meat quality of Nellore cattle produced under grazing conditions. Additionally, a cost assessment of the supplementation strategies was conducted to define the most suitable ones from an economic standpoint. Twenty-eight non-castrated male animals (18 months) with an initial body weight of 327.9 ± 4.2 kg were used. The animals were equitably distributed in a randomized complete design thorough four supplementation strategies as follows: (i) mineral supplementation (MS) in both dry and rainy seasons (MS/MS), (ii) MS during the dry season and concentrate supplementation (CS) during the rainy season (MS/CS), (iii) CS during the dry season and MS during the rainy season (CS/MS), and (iv) CS in both dry and rainy seasons (CS/CS). Thereafter, carcass traits, primary carcass cut yields, meat quality traits, and chemical composition of the meat of cattle produced across different supplementation strategies were determined. Data revealed that animals under CS/CS showed the greatest (P < 0.01) hot carcass weights among the other supplementation strategies evaluated. Conversely, supplementation strategy did not affect (P > 0.10) the carcass traits (the ribeye area, final pH, and forequarter), meat quality traits (shear force, myofibrillar fragment index, sarcomere length, and color), and meat chemical composition (crude protein, fat, and moisture) of the animals. A cost assessment of the supplementation strategies revealed that CS/CS had the highest production costs. Nevertheless, CS/CS had the greatest income and profit, while MS/MS had the lowest ones. In conclusion, data suggest that cattle grazing on tropical forage under CS during at least one season (i.e., dry or rainy) produce similar meat quality traits and chemical composition of meat to those observed for animals under CS in both seasons. Additionally, the last supplementation strategy revealed the greatest profit indicators among the other explored.

Whole or coarsely broken açai seed as a source of roughage in the diet of feedlot cattle: intake, digestibility, and ruminal parameters.

This study was conducted to evaluate the effects of two methods of provision of açai seed (AS) as a fiber source (coarsely broken or whole) for feedlot beef cattle on the intake, digestibility, and ruminal parameters. Four bulls (male, non-castrated, and rumen fistulated), with an average body weight of 340 ± 31 kg, distributed in two simultaneous 2 × 2 Latin squares, were used. The treatments were two methods of processing of the açai seed, as follows: whole açai seed (WAS), and coarsely broken açai seed (CBAS). The dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF) intake were higher (P < 0.10) with the use of CBAS. The digestibility of DM and nutrients was not affected (P > 0.10) by AS processing. Acetate and total volatile fatty acids concentrations, and acetate:propionate ratio were higher with the CBAS diet, whereas the pH was higher with the WAS diet. The concentrations of propionate, butyrate, and ruminal ammonia nitrogen (NH3) did not change with AS processing. Thus, coarsely broken açai seed increases the intake of DM and nutrients without altering the digestibility. Furthermore, it increases the concentrations of total fatty acids and acetate.

Does a high or moderate nutritional supplementation affect the puberty and productive performance of Nellore heifers?

The effects of higher supplementation levels for young Nellore heifers fed tropical forages including their influence on puberty, need to be understood. This study investigated the influence of high and moderate supplementation levels on puberty onset and the productive performance of Nellore heifers. Thirty-six Nellore heifers (225 + 3.52 kg) were used in a completely randomized design, with three treatments: (I) no concentrate (control); (II) concentrate supplement at 4 g/kg body weight (BW); (III) concentrate supplement at 8 g/kg BW. Increased supplement level led to a linear increase in average daily gain (P < 0.05). The high supplementation level (8 g/kg BW) had the highest proportion of corpus luteum presence (82% of heifers), compared to the 4 g/kg BW treatment group (67%) and the control group (33%; P < 0.05). Our findings indicate that providing a high level of energy supplementation to Nellore heifers for approximately 100 d improves performance and increases the proportion of heifers that reach puberty.

Behavior of sheep fed babassu cake (Orbygnia speciosa) as a substitution for elephant grass silage.

This study aimed to evaluate the behavior of sheep fed babassu cake as a substitution for elephant grass silage. The experiment was conducted at the Federal Rural University of Amazonia (Universidade Federal Rural da Amazônia - UFRA), Brazil, using 45 sheep housed in individual stalls, with unlimited access to feed and distributed in a completely randomized design with five treatments (0, 12.5, 25, 37.5 and 50% inclusion of babassu cake) and nine replications. All of the treatments contained a roughage-to-concentrate ratio of 40:60. No differences were observed in the time spent feeding (P > 0.05), regardless of the source of roughage used. However, there was a reduction in the time spent in rumination (P < 0.05) and an increase in time spent idling (P < 0.05) when babassu cake was included in the diet. Although there was a reduction in the time spent chewing the ruminal bolus (P < 0.05), the total daily chewing time was the same for all animals (P > 0.05). However, the sheep fed babassu cake showed higher feeding and rumination efficiency (P < 0.05). Therefore, the substitution of elephant grass silage with babassu cake can be performed at up to 50% without compromising the total time spent eating and chewing, which allows increased feeding and rumination efficiency.