Effects of feeding level and protein content of milk replacer on the performance of dairy herd replacements

Abstract

It has been suggested that United Kingdom recommendations for feeding the neonatal calf (,500 g milk replacer (MR)/day; ,200-230 g CP/kg milk powder) are inadequate to sustain optimal growth rates in early life. The current study was undertaken with 153 high genetic merit, male and female Holstein-Friesian calves (PIN 2000 5 £48) born between September and March, with heifers reared and bred to calve at 24 months of age. Calves were allocated to one of four pre-weaning dietary treatments arranged in a 2 MR feeding level (5 v. 10 l/day) 3 2 MR protein content (210 v. 270 g CP/kg dry matter (DM)) factorial design. MR was reconstituted at a rate of 120 g/l of water, throughout, and was offered via computerised automated milk feeders. Calves were introduced to pre-weaning diets at 5 days of age and weaned at day 56. During the first 56 days of life, calves offered 10 l MR/day had significantly higher liveweight gains ( P , 0.001) than calves fed 5 l MR/day. No significant differences in liveweight gain were found between calves fed 210 g CP/kg DM MR and those fed 270 g CP/kg DM MR from birth to day 56. Differences in live weight and body size due to feeding level disappeared by day 90. Neither MR feeding level nor MR CP content affected age at first service or age at successful service, and with no milk production effects, the results indicate no post-weaning benefits of increased nutrition during the milk-feeding period in dairy heifers.

The effect of calf nutrition on the performance of dairy herd replacements

“…This level of intake, approximately twice the normal feeding level used in commercial systems in the United Kingdom, was greater than that reported by Morrison et al (2009b) with calves offered 1200 g MR/day mixed into 10 l of water. When MR was fed at 120 g/l, calves were unable to consume 9 to 10 l of milk through the automatic feeding system until 4 weeks of age (Morrison et al, 2009b).…”

“…This level of intake, approximately twice the normal feeding level used in commercial systems in the United Kingdom, was greater than that reported by Morrison et al (2009b) with calves offered 1200 g MR/day mixed into 10 l of water. When MR was fed at 120 g/l, calves were unable to consume 9 to 10 l of milk through the automatic feeding system until 4 weeks of age (Morrison et al, 2009b). Elevated nutrient intakes in the first weeks of life are a key element of achieving accelerated growth; therefore, as hypothesised, increasing the mixing rate rather than volume was a more effective method of increasing MR intake when feeding calves using automatic feeding systems.…”

“…Previous studies (Bartlett et al, 2006;Morrison et al, 2009b) have reported increased blood urea concentrations with calves offered MRs with higher CP concentrations indicative of a reduction in N utilisation. However, Blome et al (2003) reported an improvement in the efficiency of N utilisation as MR CP concentration increased, whilst Bartlett et al (2006) reported an increased efficiency in CP utilisation with increasing MR feeding level.…”

“…A number of studies have reported improved animal performance when offering calves accelerated feeding regimes but few have found any long-term benefits of such regimes in later life. For example, Morrison et al (2009b) investigated the effects of both MR CP level (210 or 270 g/kg dry matter (DM)) and level of MR intake (600 g or 1200 g MR/day offered at 120 g MR/l) on calf growth and development. Despite showing increased growth rates with increasing MR feeding level at time points during the first year of life, MR feeding regime had no effect of milk production during the first or second lactation.…”

“…To achieve higher MR intakes, Morrison et al (2009b) offered calves an increased volume of MR at a fixed mixing rate but a number of authors have suggested that mixing rate should increase when adopting an accelerated growth feeding regime to ensure liquid volume does not inhibit MR intake. Diaz et al (2001) increased the MR mixing rate from 15% to 18% as the feeding level increased and achieved MR intakes of .1.5 kg/day facilitating DLWG in excess of 1 kg/day.…”