Effects of pre-weaning feed supplementation and total versus fenceline weaning on the physiology and performance of beef steers

Abstract

Forty-eight Angus steers (208 ±15 days of age) housed on pasture with their dams, were divided equally based on initial body weight (BW; 312 ± 28 kg), and assigned randomly to assess whether receiving a palatable, high fiber supplement (YS; 4.5 kg/cow-calf/day) versus no supplement (NS) for 7 days prior to weaning alters the steers' acute stress response following separation from its dam. Steers were weaned (day 0) by fenceline (FS; 12 NS and 12 YS) or total separation (TS; 12 NS and 12 YS). On day 7 the FS group was moved to a pasture lot distant from their dams and adjoining the TS group. All steers were weighed and bled on days-7, 0, 3, 7, 14, and 35 (BW only) and provided access to the supplement on days 0 to 14. By day 0, BW gain increased (P<0.01) and serum interferon-γ (IFN-γ) concentration decreased (P<0.01) in all steers. However, the YS steers exhibited greater (P<0.05) neutrophil to lymphocyte (N:L) ratio and total plasma cortisol (CORT; P=0.09) and ceruloplasmin (CER; P=0.08) concentrations compared with NS steers. From weaning to day 7, NS-TS steers initially experienced a BW loss (P<0.01) followed by a BW gain (P<0.01) when compared with the remaining steers. At 3 day post-weaning, mean hematocrit for YS steers was lower (P < 0.01) than that of NS steers and CORT was greater (P<0.05) for NS-TS vs. YS-TS steers. Red blood cell number, N:L ratio, haptoglobin and IFN-γ concentrations increased (P<0.01) in all steers by day 3 and returned to pre-weaning concentrations thereafter. From days 14 to 35, NS-FS steers gained less (P<0.01) weight compared with YS-FS and all TS steers. These results suggest that providing a high fiber supplement beginning from 7 days prior to weaning may reduce BW loss and temper the steers' acute stress response when weaned using total separation.

Comparison of effects of four weaning methods on health and performance of beef calves

“…Other studies have utilized behavior and/or biomarkers in place of, or in addition to, weight gain, while our study did not. However, those measures have often offered no discrimination ability (Burke et al, 2009;Campistol et al, 2016). It is uncertain whether the absence of evidence of differences is due to no impact of weaning method on the calf, too much variability in the data or the inappropriateness of the analytes in assessing the nature of stress induced by weaning.…”

“…In addition to the traditional approach of abrupt and complete separation from the dam, other weaning methods include initial separation from the dam by a fence which precludes suckling but permits auditory, visual and tactile contact between dam and calf (fence line weaning); use of an antisuckle device to effect cessation of suckling prior to separation from the dam (nose-flap weaning); and recently, a novel approach has been described whereby the calf is transiently removed from contact with the dam for 24 h on two separate occasions, prior to complete weaning. A number of studies have examined fence line (FL) weaning and anti-suckle nose flaps (NF), either in comparison to abrupt weaning (Price et al, 2003;Haley et al, 2005;Campistol et al, 2016) or to each other (Burke et al, 2009;Enriquez et al, 2010). To the best of our knowledge, no published research has evaluated transient separation from the dam prior to complete weaning.…”

“…Little work has been done examining impacts of various weaning approaches on these markers, but one study examining biomarkers of antioxidant stress determined two-stage weaning via NF or FL had little effect on the evaluated markers (Burke et al, 2009). Similarly, no evidence of difference was reported for levels of cortisol, haptoglobin, ceruloplasmin and interferon gamma in FL v. abrupt weaned calves (Campistol et al, 2016). The only difference in biomarkers in that study was associated with protein supplement prior to weaning; abruptly weaned, adapted steers having lower cortisol than abruptly weaned, non-adapted steers (but no substantive evidence of difference from adapted or non-adapted FL calves).…”

“…Use of FL weaning approaches has also produced contradictory findings. Campistol's group (Campistol et al, 2016) used a 2 × 2 factorial design to examine FL v. abrupt weaning and pre-weaning adaptation to a supplement v. no adaptation prior to weaning. They found that steers adapted to a supplement prior to weaning had poorer gain in the first 7 days after weaning if weaned via FL as compared to abrupt.…”

“…It is unclear why previous studies have yielded inconsistent or conflicting conclusions. Potential reasons include the use of relatively small groups (e.g., Burke et al (2009) utilized 36 steers, while Campistol et al (2016) enrolled 48); inadequate nutritional support to detect differences in performance (Haley et al, 2005); or use of a single herd/ source, which precludes in-study replication and may therefore hinder assessment of reproducibility (Bello and Renter, 2018). Regardless of cause, the general lack of repeatability makes recommendations difficult.…”