Duration To be completed March 2007
Team and Leader Drs H. Wicks, R. Fallon, L. Dawson, A. Carson, C.S. Mayne and A. Wylie
Organisations Involved ARINI, Hillsborough; Newforge; Teagasc, Grange R.O.I.
Background and Summary
Current recommendations in the UK and Ireland suggest that restricted feeding of calves (up to 8 weeks of age) of a milk replacer containing 20 to 23% crude protein is adequate to meet the calf's protein requirements.
The daily allowance of milk replacer of 450 to 750 g DM/d (at 12.5% DM concentration) fed in association with an ad libitum concentrate based feed is sufficient to achieve a live weight gain of 450 to 600 g/d between 7 to 56 days of life. Resent data from Cornell University and the University of Illinois in the USA has indicated that daily gains of between 900 to 1000g can be achieved between birth and weaning at 8 weeks of age. An increased crude protein content (23 to 30%) of the milk replacer is required to support this rate of growth, this has also been reported to increase lean tissue growth and reduce fat tissue deposition. The new "accelerated" growth system proposed by Cornell and Illinois is in sharp contrast to current calf rearing system recommended in the UK and Ireland, and requires a DM allowance of 1250 to 1500 g/d at a 15 to 18% DM concentration. Many trade magazines are currently proclaiming the merits of the new US system.
The objective of this research is to initiate research (in collaboration with Teagasc, Grange) into the nutrition/management of both dairy herd replacement and beef calves during the first 8 weeks of life, and to determine effects on lifetime performance. The study will involve feeding milk replacers with high crude protein, higher dry matter and higher intake than currently recommended.
The initial phase will be undertaken at ARINI, Hillsborough. Fifty new born calves from the dairy herd (25 autumn and 25 spring born) will be allocated to each treatment at 4 days of age. A 2 x 2 factorial design consisting of offering a daily milk replacer allowance of 600 or 1200 g dry matter per calf/day, with a crude protein content of 23% or 30% will be used. Calves will remain on the treatment until day 60, between day 54 and 60 daily milk replacer allowance will be reduced to encourage solid food intake. Calves will be grouped penned and offered their daily milk replacer allowance from a Forster automatic feeder. One Forster Technick feeder will dispense the 30% crude protein calf milk replacer and the second feeder will dispense the 23% crude protein calf milk replacer. Throughout the experimental period all calves will have ad libitum access to a calf concentrate ration and clean water. Heifer calves will be monitored through to the completion of their first lactation to assess the influence of pre-weaning diet on lactation performance. During the post-weaning, rearing phase, heifers will be offered either 2 forage based diets.
A similar 2 x 2 factorial experiment will be undertaken at Teagasc, Grange Research Centre using individually penned male calves from the dairy herd offered their daily milk replacer allowance by bucket until weaning at 60 days.
1. Production parameters of liveweight gain, feed intake etc.
2. Skeletal parameters of wither height, longissimus dorsi muscle mass etc.
3. Physiological measurement to be decided but will include plasma IGF - 1 concentration at monthly interval to determine effect of plane of nutrition in early life on subsequent IGF - 1 concentration
4. Other measurements which are likely to provide rational indicators of physiological differences
Study to commence autumn 2003, Pre-weaning offer 2 diets, monitor calf performance up to weaning; post weaning offer two forage based diets, autumn 2004/Spring 2005 heifers mated; autumn 2005 monitor lactational performance. Final report to be submitted October 2007.
a) Enable the industry to make informed decisions relating to current USA recommendations on calf growth rate
b) Quantify the increased costs associated with the higher levels of feeding in the pre-weaning phase