Dried distiller's grains for feedlot Nellore cattle fed non-forage-based diets.

This study aimed to evaluate intake, animal performance and carcass traits with the inclusion of corn dried distiller grains (DDGs) replacing cornmeal (Zea mays L.) in non-forage-based diets for finishing feedlot Nellore cattle. Sixty-four uncastrated Nellore cattle weighing 267.22 ± 20.4 kg and 18 ± 3 months old were distributed in 16 pens. Experimental diets were based on cornmeal, cottonseed cake, a mineral mixture and increased levels of DDG replacing cornmeal (0, 10, 20 and 30% on a dry matter basis). The study lasted 135 days, and the intake of nutrients and body weight gain were monitored. At the end of the study, the animals were slaughtered to measure their carcass traits. During the first 34 days of the study, the DDG levels linearly increased dry matter intake and intake of all nutrients. In other phases of the feedlot, the DDG levels did not have any effect on DMI or ADG but caused a quadratic effect on hot carcass weight. Thus, DDG can replace cornmeal in non-forage diets fed to feedlot Nellore cattle without any negative effect on intake or animal performance.

Different fat sources in supplements for beef cattle at pasture.

We investigated the consequences of fat supplementation (free oil and rumen-protected oil) on the nutrient intake and digestion of beef cattle at pasture. Five rumen-cannulated Nelore bulls, with a median body weight (BW) of 467.8 ± 32.8 kg and an age of 26 months, were distributed in a Latin square design (5 × 5). The treatments were as follows: WF, no additional fat; PA, rumen-protected palm oil; PS, rumen-protected soybean oil; SO, soybean-free oil and CO, free corn oil. Nutrient intake and digestibility, ruminal pH and ammonia (NH3-N), serum urea and nitrogen balance were analysed. The supplements with different oil sources did not alter (P > 0.05) the intake and digestibility of dry matter (DM), forage DM intake (DM), organic matter (OM), crude protein (CP), neutral detergent fibre (NDF), neutral detergent fibre-corrected ash and protein (apNDF), nonfibre carbohydrates (NFC) or total digestible nutrients (TDN) compared to WF. An increase (P < 0.05) in the intake and digestibility of EE was observed with the inclusion of fat, independent of the source. No differences were observed between WF and other supplements with regard to ruminal parameters (pH and NH3-N) (P > 0.05) and serum urea (P > 0.05). The nitrogen balance was not affected by the fat source (P > 0.05). Supplementation of grazing beef cattle (2 g/kg BW) with free oil (130 g/kg DM supplement) or rumen-protected oil (160 g/kg DM supplement) did not interfere with nutrient intake and digestibility.

Modulating the lipid profile of beef using cottonseed and crude glycerin.

The search for healthy food leads to demand for functional foods that do not harm the health of the consumers. The objective was to evaluate the impact of the supply of cottonseed and crude glycerin as modulators of the lipid profile of the beef produced on pasture. The concentrated supplement was formulated with two levels of cottonseed (0 and 25%) and/or two levels of crude glycerin (0 and 15%), totaling four experimental groups. Two experiments were conducted; the first experiment was outlined in a 5 × 5 Latin square design, contrasting the protein-energy supplementation with the mineral supplementation. The concentrate supplementation allowed the increase in intake and digestibility of the dry matter (P = 0.03), ether extract, crude protein, and non-fibrous carbohydrate (P < 0.01). However, the results showed no effect of crude glycerin or cottonseed inclusion on intake or nutrients digestibility. The second experiment evaluated the protein-energy supplementation and its impact on the lipid profile of meat produced, carcass characteristics, and animal performance. There was no influence of cottonseed or crude glycerin in performance or carcass characteristics. However, the use of the cottonseed reduced the content of short-chain fatty acids, omega 3 linolenic acid, conjugated linoleic acid (CLA) C18: 2 cis 9 trans 11 (P < 0.01), and the inclusion of crude glycerin led to increased conjugated linoleic acid (CLA) C18: 2 cis 9 trans 11 (P = 0.04). An important result is given by illustrating the impact of these fatty acids in the nutritional quality of the meat. Thus, it is possible to manipulate the lipid profile of meat produced by cottonseed or crude glycerin supplementation, without affecting the animal performance.

Effects of rumen-protected oil supplementation on finishing grazing beef cattle.

The objective of this study was to evaluate the effects of rumen-protected oil (soybean and palm oil) in supplements for beef cattle during the fattening phase in pastures on the intake and digestibility of nutrients, animal performance, and carcass characteristics. Forty-eight noncastrated male Nellore cattle (15 ± 2 months and 389.5 ± 20 kg of body weight) were used in a completely randomized design to evaluate the following treatments: protein-energy supplement (PES) without rumen-protected oil (control: CO), PES containing palm rumen-protected oil (PRPO), PES containing soybean rumen-protected oil (SRPO), and PES containing a mixture of soybean and palm rumen-protected oil (SPRPO). The study lasted 112 days, and there was a decrease in crude protein intake (P < 0.05) and an increase in ether extract intake (P < 0.05) when rumen-protected oil was included in the supplements. In comparison to the palm rumen-protected oil supplement, the soybean rumen-protected oil supplement promoted a lower average daily gain (ADG) (P < 0.05); however, regardless of the rumen-protected oil source, an increase in the fat thickness of the subcutaneous tissue was observed. In addition, there was no difference in carcass gain (P > 0.05) regardless of oil source. Rumen-protected oil is a tool to increase the finishing of pasture-finished young beef cattle in the dry season.

Effects of protein-energetic supplementation frequency on growth performance and nutritional characteristics of grazing beef cattle.

Two experiments were conducted to evaluate reduced supplementation frequencies for grazing beef cattle in rainy season. In experiment 1, evaluating the nutritional parameters, four rumen-cannulated Nellore bulls (BW = 410 kg) were used. In experiment 2, evaluating animal performance, 48 Nellore bulls (BW = 358 kg) were used. The treatments were as follows: mineral supplement (MS) alone and MS plus protein-energy supplement provided 3×, 5× and 7×/week. Supplementation frequency did not affect (P > 0.05) intake and digestibility. Average daily gain was greater (P < 0.001) to supplementation compared with MS. The supplementation 5×/week resulted in greater weight gain per hectare (9.24) and higher economic returns during the study period (1.64%) compared to other supplementations. Supplementation 5×/week increased animal performance and positively influenced economic returns.

Efficiency of nitrogen metabolism in beef cattle grazing pasture and supplemented with different protein levels in the rainy season.

Supplementation of animals in the rainy season is essential to maximise weight gain. Thus, the objective was to evaluate the effects of supplementation with low-, medium- and high-protein levels on nutritional parameters of grazing beef cattle in the rainy season. Eight rumen-cannulated Nellore bulls (437 kg body weight) were used in a 4 × 4 double Latin square design with four supplements and four experimental periods. The treatments were mineral supplement (ad libitum) and supplements with low-protein (LPSU), medium-protein (MPS) and high-protein (HPS) levels, providing 106, 408 and 601 g/day of crude protein (CP), respectively. There was no difference (P > 0.05) between treatments for dry matter and forage intake, ruminal pH, ruminal ammonia nitrogen (RAN) at time 0 (before supplementation) and microbial protein yield. Animals on MPS had a higher (P > 0.05) intake and digestibility of CP, higher RAN levels (3 and 6 h after supplementation), increased nitrogen intake and a better nitrogen balance than animals on LPSU. The HPS provided higher (P > 0.05) RAN at time 6 and a better nitrogen balance when compared with MPS. We therefore infer that the high-protein supplement positively impacts nitrogen metabolism and efficiency in grazing beef cattle during the rainy season.