PSVIII-5 Impact of Forage Allowance During mid- to Late-Gestation on the Performance of the cow/Calf Pair

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Abstract The objective was to evaluate the effect of different forage allowance in the mid to late gestation on the performance of the cow/calf pair. The experiment started at the final 151 days of gestation (D-151) until weaning (D205). Nellore cows pregnant with male calves [n = 56; 444±42 kg body weight (BW)] were blocked by the initial BW and randomly assigned to receive different forage allowances (FA): (1) Low (LFA; 2.81 kgDM)/kgBW; and (2) High (HFA; 7.58 kgDM/kgBW) until calving (d0); divided into 6 blocks and 12 paddocks of 7.5 ha each consisting of forage Urochloa brizantha cv. Marandu, without application of treatment after d0. Cows received a protein supplement (33% TDN and 50% CP) with a supply of 0.1% BW/day from d-151 to d0 and ad libitum mineral mixture from d0 to d205. Fasting BW, body condition score (BCS) on d-151, d0 and d205, mean daily gain (ADG), and milk production and composition of cows on d30, d120 and d205, and d0, d120 and d205 were used in determining ADG. The data analyzed by ANOVA using PROC MIXED, SAS 9.4. HFA cows showed greater BW, ADG and BCS with the FA × period interaction effect (P< 0.01) in D-151 to the D0. The BW was similar for cows kept in LFA and HFA, greater ADG for LFA; however, the BCS was greater for HFA from d0 to d205. Milk production and composition were not affected by the FA x period (P≥0.21). The performance of HFA calves showed greater BW with the interaction effect of FA x period (P=0.05) and without effect of FA x period (P=0.13) on ADG. In conclusion, the low forage allowance promoted a feed restriction capable of reducing the performance of the cows and consequently reducing the performance of the offspring from birth to weaning.