Performance, Carcass Traits, and Meat Fatty Acid Profile of Post-Weaning and Finishing Zebu Steers on Tropical Pasture with Three Low-Intake Supplementation Strategies.

The study aimed to evaluate the effects of three supplementation strategies on intake, apparent digestibility, feeding behavior, performance, carcass traits, proximate composition, and the fatty acid profile of meat from steers on tropical pasture during the post-weaning and finishing stages. The experiment involved 33 1/2 Holstein × 1/2 castrated Zebu steers weighing 335 ± 42.90 kg, aged 22 ± 2 m. The animals were managed on Urochloa brizantha cv. Marandu using an intermittent grazing system with continuous stocking and variable stocking rates for 310 days. The supplementation strategies were as follows: MS/US (mineral salt/urea supplementation): mineral salt in the rainy season and mineral salt with urea in the dry season; US/PS1 (urea supplementation/protein supplementation): mineral salt with urea in the rainy season and protein supplement at 1 g/kg body weight (BW) in the dry season; and PS1/PS2 (protein supplementation 1/protein supplementation 2): protein supplement at 1 g/kg BW in the rainy season and 2 g/kg BW in the dry season. The dry matter intake did not differ significantly (p > 0.05) between strategies. However, the post-weaning PS1/PS2 strategy resulted in higher (p < 0.05) crude protein intake. The final body weight did not differ (p > 0.05) between the strategies, but the average daily gain in post-weaning and finishing was higher (p < 0.05) for MS/US (restricted) animals. Carcass weight, subcutaneous fat thickness, and lipid content in meat were significantly higher (p < 0.05) for steers in the PS1/PS2 group. Steers finished on MS/US produced meat with a higher content of polyunsaturated fatty acids and ω-3 fatty acids (p < 0.05). Concentrate supplementation at 1 g/kg BW during the rainy season and 2 g/kg BW during the dry season is recommended for post-weaning and finishing steers on tropical pasture.

Effects of refused melon fruit in Canarana grass ensilage on intake, digestibility, serum biochemistry, performance, carcass characteristics and meat attributes of feedlot lambs.

Ensilage of refused fruit with forage is a viable approach to increase resource use in ruminant feed. The objective of this study was to investigate the impact of ensiling refused melon fruit (RMF) with Canarana grass on the intake, apparent digestibility, serum biochemistry, performance, carcass traits, and meat attributes of feedlot lambs. Four distinct silage treatment types were prepared by ensiling RMF at 0 g/kg (control), 70 g/kg, 140 g/kg, and 210 g/kg (as fed) with Canarana grass. Twenty-eight male Santa Inês lambs (7 lambs per treatment), initially weighing 22.3 ± 1.0 kg at 120 days of age, were distributed in a completely randomized design and confined for a total of 96 days, including a 23-day adaptation period and 73 experimental days in a feedlot. The lambs received the treatment-silage in diets as a complete mixture with a roughage: concentrate ratio of 30:70. The inclusion of RMF in Canarana grass ensilage decreased (P < 0.05) the lambs' intake of dry matter, crude protein and metabolisable energy. The inclusion of RMF in ensilage had a quadratic effect (P < 0.05) on the digestibility of non-fibrous carbohydrates. The serum total protein and cholesterol levels decreased (P < 0.05) with the inclusion of RMF in the ensilage, but we observed no effect on the final weight and average daily gain of the lambs. The feed efficiency increased (P < 0.05) by including RMF in the Canarana grass ensilage. The RMF in the ensilage did not influence cold carcass weight and yield. The fat content of the meat decreased (P < 0.05) with the inclusion of RMF in the ensilage. It is recommended the inclusion of up to 210 g/kg of RMF in Canarana grass ensilage to increase feed efficiency and avoid impacts on the performance and carcass attributes of confined lambs.

Association of rainfall pattern with the disappearance of mineral mixtures fed cattle managed on tropical pastures.

The objective of the present study was to evaluate the association between rainfall and the disappearance of mineral mixtures in the supplementation of cattle on pasture. Supplement consumption and rainfall data were obtained from five experiments carried out between 2016 and 2022. The experiments lasted from 84 to 126 days and had 12 to 18 paddocks formed by Brachiaria spp. under grazing by beef cattle (n = 544), receiving mineral supplementation. Supplement disappearance (SD), difference between the amount offered and leftovers (considering intake and losses) and precipitation (PR), was measured over periods of 14 to 21 days. The periods (n = 565) were classified as very dry, dry, normal, rainy, and very rainy, using the Quantis method. The number of rainy days (RD) and the average precipitation per RD (APRD) per period and the average body weight (BW) of the animals in the periods were also determined. Linear regression analyses assessed the association between BW, PR, RD, and APRD. The average PR in the periods studied was 68.5 mm, ranging from 0.00 to 160.3 mm. Each period had up to six RD, with up to 129.5 mm precipitated. The average BW was 270 kg, ranging from 208 to 335 kg and the average SD was 82.2 g/animal/day, ranging from 0.52 to 176.7 g/animal/day. Differences in RD and APRD are consistent across precipitation classes. In the regression analysis, the model with the highest coefficient of determination was the one that contained the linear and quadratic terms for the RD variable. Including linear and quadratic terms of all variables in a multiple regression represented more than half of the variation in the disappearance of the supplement (R2 = 0.5823). There is no clear relationship between the intensity of precipitation, reflected in the form of classes, and the disappearance of supplements offered to cattle on pasture since dry and very rainy periods can be equivalent. However, variables that characterize the precipitation pattern are more relevant than animal live weight to explain existing variations in supplement disappearance. Among them, the frequency with which precipitation occurs (number of rainy days in the period) seems to be more important than the precipitation rate itself, probably because it is related to the volume of precipitation accumulated in the period.

Cactus species and tree forage hay in the diet of dairy goats.

The purpose of this study was to evaluate the influence of the association of Opuntia stricta (OS) or Nopalea cochenillifera (NC) with Moringa hay (MY) or Leucaena hay (LY) on nutrient intake, ingestive behavior, serum biochemistry, and milk production and composition of dairy goat. Eight multiparous Saanen goats were used, with an average of 68 ± 8 days in milk and 48.5 ± 6 kg of initial weight, fed with the following treatment diets: OS + MY; OS + LY; NC + MY, and NC + LY. The treatments were distributed in a double Latin square, in a 2 × 2 factorial scheme (two varieties of cactus and two of hay). Goats fed with NC had higher (P < 0.05) intakes of dry matter, crude protein, neutral detergent fiber (NDF), and non-fibrous carbohydrates. There was no influence (P > 0.05) on milk production, but goats fed with OS produced milk with higher (P < 0.05) fat content and presented higher (P < 0.05) feed efficiency. There was no effect (P > 0.05) of the hay type on the nutrient intake and milk production and composition of goats, but the animals fed with MY had higher (P < 0.05) serum cholesterol levels and greater efficiency of NDF rumination. Goats fed with OS showed greater feeding and rumination efficiency. Our results indicated that both cactus species could be successfully included in the diet of low yielding dairy goats fed 18.4% concentrate.

Strategies of virginiamycin supplementation in the postweaning phase on growth performance and carcass quality of beef cattle.

The present study evaluated the effects of supplementing VM in grazing cattle during the rearing phase on performance and carcass quality of beef cattle in the finishing phase. Two experiments with a randomized block design were conducted in consecutive years to contrast two post-weaning supplementation strategies using VM at 45 mg/100 kg body weight (BW). In the first year, treatments were protein supplement in the dry season and mineral supplement in the rainy season versus the addition of VM both in the protein and mineral supplements. In the second year, was contrasted with protein supplement in the dry season and protein-energy supplement in the rainy season. Performance, carcass traits, and carcass quality were evaluated at the end of both phases. In Year 1, adding VM in mineral supplement increased final backfat thickness (P=0.05), backfat gain (P=0.06), final rump fat thickness (P=0.02), and rump fat gain (P=0.01). In the finishing phase, VM-treated cattle had a greater dry matter intake (P=0.03) and tended to show a greater backfat thickness than non-treated cattle (P=0.07). In Year 2, no VM effects were observed on post-weaning phase performance and carcass traits. However, cattle-fed VM during the post-weaning phase tended to show a lower feed conversion ratio (P=0.09) and had a significantly higher gross feed efficiency (P=0.03) than non-treated cattle at slaughter. Virginiamycin supplementation during rearing on pasture improves performance and carcass fattening in the growth phase and has a residual effect in the finishing phase that may reflect greater backfat thickness and gross feed efficiency.

The effect of propolis extract on milk production and composition, serum biochemistry, and physiological parameters of heat-stressed dairy cows.

The aim of this study was to evaluate whether feeding propolis extract (PE) influences nutrient intake, milk production and composition, serum biochemistry, and physiological parameters of heat-stressed dairy cows. For this purpose, we used three primiparous Holstein cows with a lactation period of 94 ± 4 days and with 485 ± 13 kg body weight. The treatments were 0 mL/day, 32 mL/day, and 64 mL/day of PE randomly assigned in a 3x3 Latin square design, repeated over time. The experiment lasted a total of 102 days; each Latin square lasted 51 days divided into three 17-day periods (12 days for adaptation and five days for data collection). The PE supply did not influence (P > 0.05) the cows' intake of dry matter (18.96 kg/d), crude protein (2.83 kg/d), and neutral detergent-insoluble fiber (7.36 kg/d), but there was an increase in feeding time with the 64 ml/day PE supply (P < 0.05). Providing 64 ml/day of PE tended (P = 0.06) to increase milk production by 11.64% and improve gross feed efficiency of cows by 12.04%. The PE supply did not influence milk composition and blood parameters of cows (P > 0.05). Offering 32 mL/day of PE decreased (P < 0.05) the rectal temperature and respiratory rate of cows. We recommend a supply of 64 mL/day of PE for heat-stressed dairy cows.

Effect of including oilseed grains in bovine diets on fatty acid profile, lipid stability, and sensory aspects of burgers.

The aim of this study was to evaluate the effect of including different oilseed grains in the diets of cattle on the qualitative and sensory characteristics and fatty acid profile of burger over a storage period of up to 120 days. The soybean diet increased 30% of ether extract in burgers when compared to the control diet. The inclusion of oilseeds in the bovine diet did not change the n-6/n-3 and hypocholesterolemic/hypercholesterolemic ratio, as well as the cholesterol levels in the burgers. The smallest flavor and aroma note scores were attributed to burgers produced with meat of bovine fed with cottonseed (4.35 and 4.67, respectively). The sunflower diet resulted in smaller lipid oxidation (1.03 mg/kg). The storage period increased lipid oxidation (0.43 and 1.97 mg/kg of malonaldehyde at 0 and 120 days, respectively). The inclusion of oilseeds in the diet of cattle does not change the ratios of fatty acids in burgers, which are important to human health. It is recommended to use soybean and sunflower grains in cattle diets to improve the sensory quality of burgers. A 30-day storage period is recommended to maintain the flavor and juiciness of beef burgers.