Effect of frequency of feed delivery on the feeding behaviour, growth, and rumen temperature of limit-fed dairy heifers

Abstract

The objective of this experiment was to determine the effect that frequency of provision of feed, provided in a restricted amount, had on feeding and lying behaviour, growth, and rumen temperature of growing dairy heifers. Twenty-four Holstein heifers (178.2 ± 9.3 d of age; mean ± SD), divided into six groups of four, were assigned to each of three treatments using a 3 x3 Latin square design with 28-d periods (21-d adaptation, 7-d data collection). Treatments were delivery of daily allotment of total mixed ration (fed at 2.0% of body weight): (1) once per day (1 x; 0800), (2) twice per day (2 x; 0800 and 1600), and (3) four times per day (4 x; 0800, 1200, 1600, and 2000). Average daily gain (ADG) was similar across treatments (0.8 kg d-1). There was a tendency for within-pen variation of ADG (average, per pen, of the absolute difference between individual heifer ADG and pen mean ADG) to be greater with 4 x (0.3 kg d-1) and 2 x (0.3 kg d-1) compared with 1 x (0.2 kg d-1). Both feeding (63.1 vs. 44.2 vs. 51.5 min d-1) and unrewarded (presence at the feed bunk when no feed was present; 49.5 vs. 27.7 vs. 33.1 min d-1) time at the feed bunk decreased with increasing frequency of feed delivery (1 x, 2 x, and 4 x, respectively). Frequency of displacements (3.1 displacements d-1) and number of displacements per unit of feeding time (0.06 displacements min-1) were similar between treatments. Lying time was similar between treatments (802.5 min d-1), while there was an increase in the amount of time spent standing without eating as frequency of feed delivery increased (558.9 vs. 590.0 vs. 604.7 min d-1 for 1 x, 2 x, and 4 x, respectively). Thus, feeding 1 x d-1 may prove beneficial for limit-fed heifers as it increases the time spent feeding, and decreases time spent standing without eating and within-pen variation in ADG.