The effects of early lactation pasture allowance and duration on milk yield

Higher stocking rates in the post-quota era, due to increased herd sizes may result in feed deficits, particularlyin early spring. The objective of this experiment was to investigate if different pasture allowances (PA) offeredto early lactation grazing dairy cows for varying time durations influenced milk yield (MY). The study wascarried out over a two year period; from March 25 to November 27, 2014 and March 9 to November 23, 2015.Each year 96 cows were assigned to a randomised complete block design experiment with a 4×2 factorialarrangement of treatments. Cows were randomly assigned from within block to one of four PA (60%, 80%,100% or 120% of estimated intake capacity; IC) for either 2 or 6 weeks. Once the 2 and 6-week time durationshad elapsed, the treatments were offered 100% of estimated IC. Milk yield was recorded daily. Data wereanalysed using covariate analysis and mixed models in SAS v9.3. Terms for year, parity, breed, PA, durationand the interaction of PA and duration were included. Pre-experimental values were used as covariates in themodel. During the first 2 weeks of the experiment there was a linear increase in MY with increasing PA (19.9,20.9, 22.3 and 24.0 kg/cow/day; 60%, 80%, 100% and 120% PA, respectively). At the end of six weeks therewas an interaction between PA and duration (P