2018•HAL (Le Centre pour la Communication Scientifique Directe)Requires access
Effect of stocking rate and breed on dry matter intake and milk production efficiency
E.L. Coffey, Luc Delaby, B. Horan
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Abstract
The objective of the experiment was to quantify the effect of stocking rate (SR) and breed on milk production, dry matter intake (DMI) and milk production efficiency across two consecutive grazing seasons (2014 - 2015) in an intensive spring calving system. Dry matter intake records were available for 68 Holstein-Friesian (HF) and 71 Jersey × Holstein-Friesian (J×HF) cows in each year of the experiment. Cows within each breed were randomly allocated to one of three SR treatments defined in terms of bodyweight (BW) per hectare (kg BW ha-1): low (LSR; 1,200 kg BW ha-1), medium (MSR; 1,400 kg BW ha-1), and high (HSR; 1,600 kg BW ha-1). Individual cow DMI was estimated three times per year: spring (March), summer ( June) and autumn (September). The effect of SR, breed, season and their interactions were analysed using mixed models. Milk production, BW and milk production efficiency per cow decreased significantly as SR increased due to reduced herbage availability per cow and increased grazing severity. As a percentage of BW, J × HF cows had greater DMI, milk solids production and milkproduction efficiency.