Weaned calves need good quality leafy pasture to grow efficiently.

To ensure calves are getting the nutrients they need, it is worthwhile weighing them and monitoring performance against live weight targets (see Table 1 below). Be aware that autumn growth rates may be limited by excess protein so hoping that summer growth deficits will disappear in the autumn may be unrealistic.

Pasture quality is highly variable. During a dry spell, pasture quality can drop to 8-9.5 MJ ME per kg DM, 9-14 percent crude protein and 52-65 percent NDF. Low quality, high NDF, pasture does not support acceptable growth rates in young animals. Calves may look full and happily chewing their cud in the paddock. But if energy and protein are limited; frame, muscle development and average daily gains will also be limited.

Calves that are more than 10 percent behind targets struggle to recover lost growth without supplementary feeding. Grass silage or a simple blend incorporating higher protein feeds like dried distillers grains or soya bean meal may be worthwhile if pasture is stemmy (for instance, high NDF). Within any mob, the lower quartile may need better quality supplementation, especially if they have been born late or suffered an early health challenge. For calves that need more help, the use of a fully balanced calf feed is warranted. NRM Grow Up 20% (if pasture protein levels are low) or Grow Up 16% (if

pastures are leafy but limited) are worth considering. Both options are high energy, low fibre feeds with additional protein from soya bean meal which contains a good balance of amino acids but won’t add to a urea overload should conditions suddenly turn wet.

Premium calf feeds contain nutritionally important extras which are not present in straights and conserved forages. For example, grains and straights can be low in calcium relative to the needs of growing animals. PKE may contain only 2.2 g calcium per kg DM which is about half the typical requirement for growing cattle. Rumen bacteria produce Vitamin B1 which is involved in the release of energy from carbohydrates and activity of the nervous system. Production is enhanced by the presence of soluble carbohydrates and soluble nitrogen in the diet. These constituents may be lacking in summer dry pasture. A range of B vitamins are included at nutritionally important levels in NRM calf feeds. Coccidia challenge is most likely in the eight weeks after weaning but the extra protection of Bovatec could be worthwhile in older calves if unfavourable conditions have aligned to hold back performance.

Weighing calves and responding to the results is an especially rewarding process. Contact your local PGG Wrightson Technical Field Representative to help organise heifer pasture testing, weighing systems and feed solutions which fit your operation. 

ARTICLE SUPPLIED BY NRM

TABLE 1 SUPPLIED BY DAIRY NZ