Productive response to two concentrate allocation strategies in dairy cows grazing with restricted pasture allowance

Abstract

The objective of this study was to compare the effects of two concentrate allotment strategies on the performance of dairy cowsgrazing on restricted pasture and supplemented with conserved forage. Dairy cows fed equal amounts of concentrate (fixed daily rate:5.5 kg DM/cow) were compared to cows supplemented with concentrate according to their lactation stage as follows: 10.0, 5.0, and 1.5kg DM/cow daily during early, mid, and late lactation, respectively (average daily dose: 5.5 kg DM/cow). There was a supplementationstrategy × lactation stage interaction (P < 0.05) for energy-corrected milk (ECM). For early lactation cows, supplementation at a variablerate increased ECM yield by 14.61% (P < 0.05). There was a supplementation strategy × lactation stage interaction (P < 0.05) for bodyweight change. At late lactation stage, cows supplemented at a fixed rate gained weight (+ 0.16 kg/day), whereas those supplemented ata variable rate lost weight (– 0.08 kg/day; P < 0.05). No significant effect was found for body condition score. The prioritization of milkproduction rather than the attenuation of body reserve mobilization suggests that concentrate allowance based on lactation stage maybe unsuitable for minimizing the negative energy balance in early lactation cows.