Feeding weanlings during the winter

Grange research has shown that weanling steers and heifers generally do not require protein supplementation when fed barley-based concentrates and high DMD grass silage. Researcher Mark McGee and Specialist Catherine Egan give some information and advice.

To minimise feed costs and exploit subsequent compensatory (“catch-up”) growth at pasture during the following grazing season, live weight gains of 0.5-0.6 kg/day through the first winter is acceptable for steers, heifers (and suckler bulls) destined to return to pasture in spring.  Research at Teagasc Grange has shown that there is little point in over-feeding weanlings in winter as, during the subsequent grazing season, cattle that gained less over the winter had the highest live weight gain at pasture, resulting in most of the winter weight advantage ‘disappearing’ by the end of the grazing season. However, cattle growing too slowly during winter (<0.5 kg/day) will not be able to compensate sufficiently at pasture, and consequently, will not reach target weights later in life. 

Dry matter digestibility (DMD) is the primary factor influencing the nutritive value of grass silage and consequently, the performance of cattle. Target animal growth rates during the first winter can be achieved on grass silage supplemented with concentrates as outlined in Table 1. Low DMD silage means higher levels of concentrate supplementation have to be used to achieve the same growth rates; this highlights the importance of having good silage ‘quality’ for growing cattle. 

 Energy is the most important nutrient required by growing cattle.  Recent studies at Teagasc Grange have shown that for growing ‘weanling’ cattle, soya hulls and citrus pulp can replace rolled barley (balanced for protein) in concentrate rations offered at relatively low levels (ca. 2 kg/day), as a supplement to high digestibility grass silage, without negatively affecting performance.

Grange research has shown that weanling steers and heifers generally do not require protein supplementation when fed barley-based concentrates and high DMD grass silage, but for suckler bull weanlings, recent research showed a significant, but small, response to protein supplementation. However, weanlings are likely to respond to supplementary protein in barley-based concentrates when grass silage has moderate to low DMD and/or low protein content.

Mark McGee and Catherine Egan, Teagasc, AGRIC

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