Milk production and reproduction of dual-purpose cows with a restricted concentrate allowance and access to an association of Leucaena leucocephala and Cynodon nlemfuensis

摘要

The aim of the study was to evaluate the productive and reproductive performance of dual-purpose (DP) cows with a restricted concentrate allowance and access to a forage association of Leucaena ( Leucaena leucocephala ) and Stargrass ( Cynodon nlemfuensis ). Twenty-four multiparous Holstein ???? Zebu cows were used during the first 98 days postpartum. Treatments were control (CT): nightly grazing of Stargrass + commercial concentrate (3.97 kg dry matter [DM]/d), and Leucaena (LT): nightly grazing of Stargrass + commercial concentrate (1.97 kg DM/d) + 4 h grazing on an association of Leucaena/Stargrass. The actual time spent browsing Leucaena represented 38% of the total time of consumption. The bite rate of Leucaena was 22 5 bites/min with a bite size of 0.541 ???± 0.08 g DM. The estimated intake of Leucaena per cow was 503 ???± 228 g DM/d. Milk yield per cow was similar ( P > 0.05) between treatments (CT = 12.28 ???± 0.6 kg/d, LT = 11.97 ???± 0.6, TL = 11.9 0.6) with a similar composition ( P > 0.05). There were no differences ( P > 0.05) between treatments for changes in live weight (CT ?￠????29.6 kg, LT ?￠????33.3 kg) and body condition (CT ?￠????1.3, LT ?￠????1.4, in a 1?￠????9 scale). Population of ovarian follicles per cow was similar between treatments throughout the experiment. Pregnancy rate was 33% for CT and 25% for LT, with no significant differences ( P > 0.05). Grazing an association of Leucaena and Stargrass can replace part of the concentrate without detrimental effects on production and reproduction in DP cows.