The effects on growth, food intake and rumen volume of including untreated or ammonia-treated barley straw in a complete diet for weaning calves

Abstract

Two experiments were conducted using British Friesian bull calves to determine the effects on growth, food intake and rumen volume of including 0, 150, 200 or 250 g ammonia-treated (35 g/kg dry matter (DM)) or untreated barley straw per kg pelleted concentrate based on cereal. All calves received once daily 440 g milk replacer powder reconstituted in 3 1 warm water, were weaned at 56 days of age and given one of the seven pelleted diets to appetite from 14 days of age. In experiment 1, the seven diets were allocated at random to 70 calves. Food intake was increased by the inclusion of straw but there was no effect on intake of the increased concentration of straw; daily DM intake from 14 to 77 days of age was 1·36 and 1·77 kg/day respectively for diets with or without straw. From 14 to 56 days of age intake of concentrate was increased by the addition of straw but was negatively correlated with the concentration of straw in the diet. After weaning inclusion of straw, whilst increasing total intake, tended to depress intake of cereal. Treatment with ammonia increased the nitrogen concentration in the straw but had no effect on the digestibility or amount of diet consumed. After adjustment was made for gut fill, the increases in weight between 4 and 84 days of age of calves given 150, 200 or 250 g straw per kg food were 6·6, 1·2 and 1·0 kg respectively greater than those that occurred when there was no straw in the diet. DM digestibility of all diets was above 0·67 but the mean digestibility of acid detergent fibre was low (0·19). The pH and ammonia concentration of rumen liquor were low and below the optimum for cellulose digestion. In experiment 2, rumen volume was measured in vivo in a group of 24 calves given the same diets as in experiment 1. Rumen volume was increased two fold at 42 days of age by the addition of straw to the diet (5·6v.2·6 1,P< 0·001), by 87 days of age the difference was increased to 7·11, (19·0v.11·9 1,P< 0·01). When all calves were given the same diet from 91 days of age, there was no effect of previous treatment on intake or rumen volume at 147 days of age.

The effects of hay and silage on growth and rumen function in young Holstein calves

“…Bines and Davey (1978) showed that the percentage ofroughage as straw in the diet caused a buffering effect in the rumen that lasted for at least 3.5 h. Williams et al (1985) showed that as the amount of barley straw in a complete diet for calves was increased from 0 to 25%, rumen pH increased bY about 1 unit. They (Williams et al 1985) were also found in the current trial. Bines and Davey (1978) found that increasing the percent of barley straw in the diet of mature iows decreased the amount of each of the VFAs found in the rumen fluid.…”

Developmental changes in clearance of intravenous doses of glucose, acetate and β-hydroxybutyrate from plasma of calves

“…Bodyweight gain after weaning was faster on 20%AM compared to CON and CC, and final BW was higher for calves consuming AM compared to CON and CC. Williams et al (1985) observed significantly higher preweaning DMI and BW gain in calves fed a pelleted starter containing 15% chopped straw compared to no straw. The improvement in DMI was attributed to the elevation in rumen pH that was observed.…”

“…Increased weight gain in calves consuming a higher amount of roughage might be due to an increased weight of digesta remaining in the digestive tract (Williams et al, 1985). At slaughter, the 10 and 20%AM calves had up to 1.5 kg more digesta in the digestive tract than CON or CC calves (Table 2).…”

Effects on food intake, rumen development and live weight of calves of replacing barley with sugar beet-citrus pulp in a starter diet

“…Numerous experiments have suggested that ruminal volatile fatty acids (VFA) are chemical stimulants of rumen mucosal growth and that inert bulk materials serve as physical stimulants for rumen muscular growth and increased rumen volume (Thivend, Toullec and Guilloteau, 1980). Williams et al (1985b) concluded that the pH of rumen contents was a major factor influencing voluntary food intake of calves and demonstrated that using unmolassed sugar-beet pulp rather than barley as the major energy source produced a higher (5-42 v. 4-94) and more stable rumen pH in the calf compared with the diet based on barley (Williams, Fallon and Innes, 1985a). The replacement of barley with pulp increased the intake of dry diet and daily live-weight gain of the calves although the overall DM digestibility of the diet was depressed, suggesting that the composition of the dry diet significantly affects voluntary food intake.…”

“…In experiments which have demonstrated a beneficial effect on intake from the inclusion of roughage in all-pelleted diets based on cereals, the appetite of the calf may have been constrained by low fibre digestion (Thomas and Hinks, 1983;Williams, Innes, Brewer and Magadi, 1985b). In experiments which have demonstrated a beneficial effect on intake from the inclusion of roughage in all-pelleted diets based on cereals, the appetite of the calf may have been constrained by low fibre digestion (Thomas and Hinks, 1983;Williams, Innes, Brewer and Magadi, 1985b).…”