Performance, ruminal changes, behaviour and welfare of growing heifers fed a concentrate diet with or without barley straw

Abstract

Two experiments were conducted to ascertain the effects of feeding an all-concentrate diet to growing heifers on performance, ruminal fermentation, behaviour and welfare. In experiment 1, eight tethered rumen fistulated Holstein heifers (143 6 8.7 kg, initial BW) were used to study the effects of treatment on intake, ruminal changes and behaviour. In experiment 2, 48 Friesian female calves (initial BW 5 84.5 6 1.37 kg) were used to study the effects of treatment on performance, behaviour and welfare in feedlot conditions. In both experiments, treatments consisted of concentrate with barley straw (BS) or without barley straw (NBS) and feed was offered at 0830 h on an ad libitum basis. Experiment 1 was performed in four 42-day periods, and sampling was carried out in the last week of each period. Ruminal samples were collected over 3 days at 0, 4, 8 and 12 h post-feeding to measure pH, and volatile fatty acids (VFA) and NH 3 -N concentrations. Maintenance behaviour was video-recorded for 24 h over three consecutive days of each experimental period and feed intake pattern was studied by means of feed bunks mounted on digital platform scales. There were no statistical differences in average daily gain (ADG), concentrate dry matter (DM) intake or CP intake. In contrast, NDF intake and ADF intake were greater in heifers fed BS than NBS. Average ruminal pH was lower, whereas total VFA was greater, in heifers fed NBS diet. There were no differences in NH 3 -N, and in D-and L-lactate concentrations. Time spent in ruminating was shorter, and stereotypies were more frequent in heifers fed diet NBS compared with those fed BS. In experiment 2, nine 28-day periods were established, in which DM intake and ADG were measured, blood and faecal samples were taken for haptoglobin and glucocorticoid metabolites determination, respectively, as welfare indicators, and behaviour was monitored by video recording. Concentrate intake was similar in both treatments, but total feed intake was greater in heifers fed BS diet. As there were no differences in ADG between treatments, gain efficiency was lower in those fed BS than those fed NBS. Blood haptoglobin and faecal glucocorticoids metabolites were not different between treatments. In these competitive conditions, rumination was also reduced and stereotypic behaviour increased by straw exclusion. In conclusion, performance was either not affected or improved by straw exclusion, but animal behaviour was affected, suggesting a negative effect on animal welfare.

Acute phase proteins in ruminants

“…Haptoglobin and fibrinogen concentration did not differ in veal calves fed corn moderately contaminated with Fusarium mycotoxins demonstrating that the calves were tolerant to the levels of the toxin in the diet [207]. The serum Hp concentration was not altered by an allconcentrate diet [208]. Haptoglobin and M-SAA3 in milk were used in assessment of the effect of a dietary negative energy balance diet on S. uberis induced mastitis and showed that the lower energy balance diet used in the study had a minimal effect on immune function [209].…”

Animal performance and meat characteristics in steers reared in intensive conditions fed with different vegetable oils

“…In such a system, the consumption of concentrate makes up >90% of the total ration (Faleiro et al, 2011). As a result, the profitability of the production system depends largely on reducing the fattening time.…”

Performance, behaviour and meat quality of beef heifers fed concentrate and straw offered as total mixed ration or free-choice

“…Devant et al (2000) reported that the proportion of concentrate and barley straw consumed by crossbred heifers changed from 95% and 5% at 80 kg body weight (BW) to 92% and 8% at 230 kg BW. In other studies, when Friesian heifers were also offered concentrate and barley straw separately and on an ad libitum basis during the fattening period, the average proportion of concentrate and barley straw intake was 90% and 10%, respectively (Robles et al, 2007;González et al, 2008;Faleiro et al, 2011). In these feeding conditions, rumination and chewing activity is more limited than when roughage is consumed in 2 shavings, in groups of three heifers per pen.…”