The objective of this work was to evaluate the characteristics of the maternal-offspring behavior of Guzerat bovines (Bos indicus) and the influence of this behavior on herd losses. A total of 73 gestating cows (multiparous and primiparous) and their respective calves were evaluated for the following behavioral traits: contact period between cow and calf (CPCC), cow age at calving, teat conditions, calf vigor at birth, need for human assistance (HA), and calf mortality until weaning. The mean weight of calves at birth was 29.12 kg. Vigor at birth was observed in 61.64% of calves; however, 27.4% of the calves required human assistance. Calf vigor was influenced by the CPCC, and calves without vigor needed more time with their mothers. Calves with low weight at birth required HA, whereas calves from cows with intermediate-sized teats did not. The absence of vigor at birth increased the mortality rate. The traits age of cows and vigor of calves at birth influence both the need for human assistance to calves in their first hours of life and herd losses.

Context Maternal ability, cow nutrition, and calf sex are factors that affect beef cattle production in extensive systems. The Guzerá cattle is an important breed in Brazil, where satisfactory growth rates are reported; however, studies on post-parturition calf and cow behaviour are scarce. Aims This study aimed to identify the influence of vigour at birth (ability to stand and suckle without assistance) and human assistance in colostrum intake (HA) on the haematological profile, cortisol concentration, and growth until weaning of Guzerá beef calf. Methods The following traits were observed in 73 male and 83 female calves: cow age at calving, sex, birthweight, vigour, HA, haematological profile, cortisol concentration, bodyweight at 120 days (W120), weaning weight, average daily gain and mortality. Variance analysis was performed using the general linear model procedure of the SAS software. Key results Haematocrit (P = 0.04) and red blood cells (P = 0.004) were higher in calves requiring HA. Cortisol was also higher (P = 0.03) in calves that required HA (81.34 ng/mL × 59.40 ng/mL). The weaning weight and average daily gain were higher (P < 0.05) in calves that did not require HA and showed good vigour (200.38 kg and 0.83 kg/day respectively) than in calves that required HA and showed good vigour (163.7 kg and 0.68 kg/day respectively). The mortality rate was higher in calves that showed poor vigour at birth (25%). Conclusions Both vigour and the need for HA are important traits that should be evaluated during the development of newborn calves. These assessments in the herd can contribute to minimise the mortality rate and maximise the health and weight gain until weaning of beef calves. Implications Few studies have reported the role of vigour and colostrum intake in the development of calves. Despite the difficulty of human interference in extensive cattle farming, the calf vigour combined with human assistance at birth can minimise the losses and increase the performance of beef cattle.

In this study, we evaluate the effects of intercropping pigeon pea (Cajanus cajan (L.) Millsp.) with tropical pastures for feeding Nellore cattle and compared animal performance and enteric CH4 emissions with other pasture-based systems during the dry and rainy seasons of 2021. Thirty-six Nellore steers (with a body weight of 221 ± 7 kg and an age of 15–16 months) were randomly distributed in three treatments with three replicates (in paddocks of 1.5 hectares each): (1) a degraded pasture of Urochloa spp. (DEG); (2) a recovered and fertilized pasture of Urochloa spp. (REC); and (3) pigeon pea intercropped with Urochloa spp. (MIX). Enteric CH4 emissions were estimated using the sulfur hexafluoride (SF6) tracer gas technique, and dry matter intake (DMI) was determined using internal (iNDF) and external (TiO2) markers. Forages were collected by hand plucking after observations of ingestive behavior, and feces was collected after voluntary defecation. The proportion of grass and legume intake was estimated by C stable isotopes, and the forage nutritional quality was determined, while animal performance was monitored monthly, and the stocking rate was adjusted by the “put and take” technique. The results indicated that intercropping pigeon pea with tropical grasses is an interesting strategy for sustainable livestock production based on pastures. The MIX treatment was able to meet the nutritional requirements of the animals, which presented higher performance. In addition, there was a reduction in CH4 emissions up to 70% when expressed per average daily weight gain in comparison to the DEG treatment.

Context The beef market faces an increasing demand for an environmentally friendly production system with high-quality final products. The use of strategies that improve system efficiency without detriment on quality are desired for both producers and consumer. Aims This study aimed to evaluate the effects of residual feed intake (RFI) and dietary inclusion of crude glycerin on carcass and meat quality traits of feedlot-finished Nellore cattle. Methods Nellore bulls selected for growth and classified as high (n = 14) and low (n = 14) RFI, with average liveweight of 328 kg and age of 552 days were used. Bulls received a high-concentrate diet for 96 days before slaughter and were randomly allocated to two experimental diets in a 2 × 2 factorial arrangement: RFI class (low or high) and dietary inclusion (CG) or not (WCG) of crude glycerin (20% on dry-matter basis). Data were analysed with the SAS MIXED procedure considering RFI class and diet as fixed effects and selection line as a random effect. Key results There were no significant differences between RFI classes for dry-matter intake during finishing or production traits. Dry-matter intake tended to be reduced by 16% in CG bulls, without alterations in production. Dietary glycerin inclusion tended to increase the protein content in the Longissimus muscle and significantly reduced the fat content. In low-RFI bulls, shear force was higher in unaged beef, and shear force and myofibrillar fragmentation index tended to be higher in meat aged for 14 days. RFI class did not affect Longissimus muscle fatty acid profile, which was highly influenced by dietary glycerin inclusion. Bulls allocated to the CG treatment had a reduction in saturated fatty acids, an increase in odd-chain fatty acids, and a trend towards increased omega-3 fatty acids, which significantly increased the omega-3:omega-6 ratio. Conclusions The use of Nellore bulls classified as low-RFI and crude glycerin inclusion in finishing diets of Nellore cattle do not compromise production, carcass traits or beef properties. Implications This approach increases the efficiency and sustainability of the production process and improves the nutritional characteristics of beef for human consumption.