Early step-down weaning of dairy calves from a high milk volume with glutamine supplementation

Abstract

Weaning dairy calves from a high milk volume (≥8.0 kg/d) can negatively affect the growth and welfare even if it is performed in a step-down manner. Supplementation of Gln improved gut development of preweaning calves and mitigated weaning stresses of piglets to extents achieved with antibiotics. The study objective was to examine the effect of initiating a step-down weaning scheme with a Gln supplement at an early age on calf starter intake (CSI), average daily gain (ADG), and paracellular permeability of the intestinal epithelium of calves fed a high volume of milk (9.0 kg/d). Thirty-six Holstein heifer calves were assigned to 3 treatments (n = 12) as follows: (1) initiating weaning at 49 d of age (LW), ( 2) initiating weaning at 35 d of age (EW), and (3) initiating weaning at 35 d with a Gln supplement (2.0% of dry matter intake) from 28 to 42 d of age (EWG). Calves were fed 9.0 kg/d of whole milk until weaning was initiated by abruptly decreasing the milk volume to 3.0 kg/d. Weaning was completed once calves achieved ≥1.0 kg/d of CSI. The paracellular permeability of the intestinal epithelium was assessed with lactulose-tomannitol ratio (LMR) in the blood on 1 d before, and 3 and 7 d after the initiation of weaning. The blood was analyzed for haptoglobin, lipopolysaccharide-binding protein (LBP), and metabolites including AA. The CSI increased once milk volume was restricted in all treatments. The CSI of LW was greater than that of EW and EWG during the first week of weaning. The LW, EW, and EWG took 11, 19, and 16 d to achieve ≥1.0 kg/d of CSI and were weaned at 60, 54, and 51 d of age, respectively. The body weight (BW) of LW, EW, and EWG at the initiation of weaning were 68.2, 58.7, and 59.5 kg, respectively. Both LW and EWG achieved similar ADG, but ADG of EW was lower than LW during the first week of weaning. All calves had similar ADG during the second week of weaning. The BW of LW, EW, and EWG at weaning were 74.8, 66.5, and 66.4 kg, representing a 2.0, 1.8, and 1.8-fold increase in birth weight, respectively. All calves had similar BW of 88.6 and 164.3 kg at 10 and 20 wk of age, respectively. Regardless of the age, serum haptoglobin and plasma LBP concentrations increased on d 3 and returned to baseline concentrations on d 7 during weaning. The EW had a lower plasma LBP concentration than LW and EWG on d 3 during weaning. The LMR was similar between treatments on d 3 but increased by 44% for EW and LW on d 7, whereas the LMR of EWG remained unchanged during weaning. The postprandial serum concentration of Gln, Met, Trp, and β-hydroxybutyrate were greater for EWG than EW during weaning. Beginning step-down weaning at 35 d with a Gln supplement can help maintain the gut barrier function and wean dairy calves with a satisfactory CSI at 7 wk of age without affecting postweaning growth.

Early Stepdown Weaning of Dairy Calves with Glutamine and Branched-Chain Amino Acid Supplementations

“…Amino acid (AA) supplements were fed in milk over the last 3 d pre-weaning and in the first week during weaning (33 to 42 d of age). The Gln supplementation was 8.0 g/d, which was predicted to be equivalent to 1.0% of the DMI (milk solid and starter dry matter) of calves [ 13 ]. The 1.0% supplementation was chosen as Gln has been shown to improve the weaning performances of piglets with supplementations ≤1.0% of dry feed intake.…”

“…The sample size was determined with a power analysis (power = 0.80 and α = 0.05) to capture the increase in the average SFI of calves undergoing the present weaning scheme from 0.55 [ 13 ] to 1.0 kg/d [ 10 , 11 ] given that the standard deviation of SFI was 0.36 kg/d [ 13 ]. Treatment effects on the responses of interest were determined by using the following statistical model: Y ijklm = μ + T i + P j + R k + W l + (T × P) ij + C m + e ijklm , where Y ijklm = the response variable of interest; μ = the overall mean of the response; T i = the fixed effect of the ith treatment (i = CTL, GLN, and GLNB); P j = the fixed effect of the jth period (j = pre-weaning, during weaning, and post-weaning); R k = the fixed effect of the kth parity of the dam (k = primiparous and multiparous); W l = the fixed effect of the lth week born (l = 1, 2, 3,…, 8); (T × P) ij = the fixed effect of the interaction between the ith treatment and jth period; C m = the random effect of the mth calf; and e ijklm = the random error assumed to be independent and identically distributed from a normal distribution with a mean of 0 and a variance of σ 2 (~N (0, Iσ 2 )).…”

“…In that scheme, calves had lower ADG during weaning as well as post-weaning compared to calves that were weaned 14 d later. Wickramasinghe et al [ 13 ] employed a similar scheme but avoided the post-weaning growth slump by delaying complete weaning until calves achieved a 1.0 kg/d SFI. Moreover, Wickramasinghe et al [ 13 ] demonstrated that supplementing Gln (2.0% of DMI) increased ADG during weaning and helped calves achieve the 1.0 kg/d SFI earlier than calves that were not supplemented with Gln.…”

“…Glutamine is a predominant energy substrate of enterocytes, and Gln deficiency exacerbates the weaning-induced damage to the intestinal barrier function and absorptive capacity of the small intestine [ 14 , 15 ]. Wickramasinghe et al [ 13 ] showed that supplementation of Gln alleviated the damage to the paracellular permeability of intestinal epithelium of calves undergoing weaning at 35 d of age. The authors speculated that offering some volume of whole milk until calves consumed ≥1.0 kg/d SFI led to a successful recovery from early weaning without negatively affecting SFI and ADG post-weaning.…”

“…They stimulate protein synthesis and cell proliferation and play critical roles in the growth and development of young calves [ 17 , 18 ]. The BCAA could limit growth during weaning as serum BCAA concentrations decreased more rapidly in calves with positive ADG during weaning than calves with no ADG during weaning [ 13 ]. Ren et al [ 19 ] demonstrated that supplementing a low-protein diet with BCAA increased feed intake and the ADG of weaning piglets, which could be positively correlated with the future growth performances [ 20 ].…”