Effects of monensin in supplements for beef cattle in tropical grazing systems during the rainy season.

Two experiments were carried out to evaluate the effect of monensin in supplements for grazing heifers. In experiment I, treatments consisted of protein supplements (low intake - 0.5 kg/animal/day and high intake - 1.0 kg/animal/day) associated or not with monensin. Animal performance, nutrient intake, and digestibility were evaluated. Forty crossbred heifers with an initial body weight (BW) of 213.8 ± 4.5 kg were used. There was no difference in average daily gain between treatments (average of 0.588 kg/animal/day). There was no interaction between monensin and supplements for intake parameters and digestibility. Dry matter (DM) intake was equal between treatments (~ 2% of BW). However, there was a reduction in pasture intake with the high-intake supplement. In experiment II, treatments consisted of two types of supplements (protein or mineral) associated or not with monensin. The variables analyzed were productive performance, ingestive behavior, and thermal comfort, evaluated through the index of thermal stress for cows (ITSC). Forty crossbred heifers with a BW of 159.2 ± 1.3 kg were used. The type of supplement did not influence the performance of the animals. However, monensin promoted greater weight gain in the animals (110 g/animal/day). There was an interaction effect between supplementation and monensin addition on behavioral activities, except for idle time. The inclusion of monensin in the protein supplement reduced the grazing time. The ITSC value influenced the activities of ingestive behavior, and the increase of this index reduced the grazing time in all treatments. Forage quality influences the response to monensin use, and the addition of monensin in supplements for grazing cattle during the rainy season is recommended for forages with high CP content.

Rumen fermentation and metabolic profile of rams fed with diets amended cottonseed cake.

The aim of the study was to evaluate the addition of increasing cottonseed cake contents in the diet. The diets were composed of corn silage (500 g kg-1) and concentrate feed (500 g kg-1) on a dry matter (DM) basis. The treatments consisted of the substitution of 0, 140, 280, and 420 g kg-1 soybean meal to cottonseed cake in the DM of concentrate feed. Four rams of the Santa Inês breed, average age of 12 months and average weight of 27.77 ± 3.87 kg, were distributed in a Latin square design (4 × 4) in a split-split-plot design, with diets in the plots and as subplots were 5 days of collection and the collection times. The results were subjected to analysis of variance and regression at 5% probability. The soybean meal substitution contents by cottonseed cake in the concentrate increased linearly the pH (P = 0.019). Ruminal ammonia-nitrogen concentration decreased linearly by 0.0137 mg dL-1 at each 10 g/kg of substitution and the time after feeding promoted the same effect (P < 0.001) decreased linearly by 0.6204 mg dL-1 at each hour after feeding. There was an increased linearly of 0.0116 mmol mL-1 at the concentration of propionic (P = 0.008) and a reduction of 0.0062 mmol mL-1 at the concentration of butyric (P = 0.009) with cottonseed cake content; however, the substitution did not influence the others short-chain fatty acids. Replacement of soybean meal with cottonseed cake in the sheep feed did not significantly alter the blood parameters, promoting minor changes in the ruminal parameters mainly in the ruminal ammonia-nitrogen without affecting the animal's health.

Effects of Streptococcus bovis Isolated from Bovine Rumen on the Fermentation Characteristics and Nutritive Value of Tanzania Grass Silage.

This study aimed to evaluate the effects of Streptococcus bovis on the fermentation characteristics and nutritive value of Tanzania grass silage. Tanzania grass was chopped and left untreated (U) or treated with Streptococcus bovis JB1 at 1 × 10(6) colony-forming units per gram (cfu/g) of fresh forage or Streptococcus bovis HC5 at 1 × 10(6) cfu/g of fresh forage and packed into sixtuplicate laboratory silos. The largest number of enterobacteria, molds and yeast (M&Y) occurred in untreated silages and the smallest populations of enterobacteria and M&Y and the largest numbers of lactic acid bacteria (LAB), at 9.81 and 9.87 log cfu/g, were observed in Streptococcus bovis JB1 and HC5, respectively (P < 0.05). Silages treated with JB1 and HC5 had lower (P < 0.05) silage pHs and concentrations of ammoniacal nitrogen (NH3-N) than untreated silages. The application of Streptococcus bovis JB1 and HC5 resulted in fewer losses through gases and effluents (P < 0.05), which resulted in greater dry matter recovery (DMR) and crude protein recovery (CPR) (P < 0.05). Streptococcus bovis JB1 and HC5 improved the fermentative profile and increased the concentration of crude protein and DMR and CPR in Tanzania grass silage.