The effect of early weaning on feedlot performance and measures of stress in beef calves1,2

Abstract

Forty crossbred steers (Brahman x English) were categorized into two groups: 1) early weaned (EW; n = 20); and 2) normal weaned (NW; n = 20). Calves were 89 and 300 d of age at the time of EW and NW, respectively; SEM = 4.4. Early-weaned calves were kept on-site (University of Florida, Ona), provided supplement (1% of BW), and grazed on annual and perennial pastures until NW. At the time of normal weaning, all calves were loaded on a commercial livestock trailer and transported to the North Carolina State University Research Feedlot in Butner (approximately 1,200 km). Upon arrival, calves were stratified by BW and randomly allotted to four pens per weaning age treatment. Individual calf BW and blood samples were collected at the time of normal weaning, on arrival at the feedlot (d 1; 24 h following weaning), and on d 3, 7, 14, 21, and 28 of the receiving period. Individual BW was collected at the start and end of the growing and finishing periods, and feed intake by pen was measured daily. As an estimate of stress during the receiving period, plasma was collected and analyzed for the acute-phase proteins, haptoglobin and ceruloplasmin. Early-weaned calves were lighter (P = 0.03) at normal weaning than NW calves (221 vs. 269 kg; SEM = 10.6). By d 28, EW calves tended (P = 0.12) to be lighter than NW calves (242 vs. 282 kg, respectively). Gain:feed was improved for EW compared with NW calves during both the receiving (G:F = 0.157 vs. 0.081) and growing (0.159 vs. 0.136) periods. There tended (P < 0.10) to be weaning age x day interactions for each acute-phase protein. Ceruloplasmin concentrations increased in NW, but not EW calves, and peaked on d 7 (27.6 and 34.2 mg/100 mL for EW and NW calves, respectively; P < 0.05). Haptoglobin concentrations increased in both groups and were greatest (P < 0.05) in NW calves on d 3 (7.63 vs. 14.86 mg of haptoglobin/hemoglobin complexing/100 mL). No differences in ADG or G:F were detected during the finishing phase; however, overall G:F was improved (P = 0.03) for EW vs. NW calves (0.155 vs. 0.136). Carcass measures, including backfat thickness, USDA yield grade, marbling score, and LM area, did not differ between treatments. These data imply that EW calves, which are maintained onsite before shipping, may be more tolerant to the stressors associated with transportation and feed yard entry. Early weaned calves, managed within the system described in this study, may have improved G:F.

Animal performance and economic implications of alternative production systems for dairy bulls slaughtered at 15 months of age

“…Utilising pasture in a 15-mo bull production system can reduce the overall costs of production, but this also presents the challenge of achieving the required market specifications. Although numerous studies have investigated the effects of calf nutrition on performance during the finishing period, many of those studies focussed on the influence of pre-weaning nutrition (Arthington et al, 2005;Wolcott et al, 2010). Wolcott et al (2010) reported that suckled Shorthorn calves weaned at 259 d of age were 17 kg heavier at the start of the finishing period and had 18 kg greater carcass weight at 23 mo of age compared to those weaned at 123 d of age.…”

“…Wolcott et al (2010) reported that suckled Shorthorn calves weaned at 259 d of age were 17 kg heavier at the start of the finishing period and had 18 kg greater carcass weight at 23 mo of age compared to those weaned at 123 d of age. Arthington et al (2005) 2009), the 15-mo bull production system is dependent on high levels of concentrate input. Consequently, the proportion of grazed grass in the feed budget is limited.…”

Some physiological and biochemical methods for acute and chronic stress evaluationin dairy cows

“…In this situation, other usual functions of the liver, such as gluconeogenesis (Elsasser et al, 2000), bilirubin excretion (Assenat et al, 2004) and others, can be reduced. Thus, among the mechanisms of the well known negative effects of inflammations, mainly when they are prolonged, the changes in liver functionality could be of great interest and could be useful markers of a chronic stress condition ("disease" stress) in dairy cows (Bertoni, 1999;Bertoni et al, 2008;Lomborg et al, 2008) as well as in beef cattle (Arthington et al, 2003;Arthington et al, 2005) and in pigs (Piñeiro et al, 2007). In particular, the -APP represent promising indicators of chronic stress/reduced welfare during the transition period, as demonstrated in various experiments (Bertoni et al, 2006a;Bionaz et al, 2007;Bertoni et al, 2008), because they are linked to the effects of prolonged and severe inflammation, which cause their marked reduction and reduced level of welfare.…”

Effect of age at weaning on the physiological stress response and temperament of two beef cattle breeds

“…Moreover, age at weaning and level of nutrition affect the cellular (Pollock et al, 1993) and humoral immune responses of young calves (Pollock et al, 1994) and may influence their general stress response. In fact, early-weaned calves were more tolerant to stressors associated with transport and feedlot entry than their traditionally weaned counterparts (Arthington et al, 2005). Stress response may also be influenced by breed, because genetic factors can be important in the neuroendocrine and metabolic adaptation to stressing conditions (García-Belenguer et al, 1996).…”