With the change in weather in recent weeks, many farmers are housing youngstock this week to stretch available grass supplies for the cows on dairy farms. Heifers tend to do more walking around in wet weather and thus more damage than cows. If they are on outside blocks with sufficient grass, moving to 24-hour breaks and back-fencing will help to reduce damage.
If grass is scarce, and it’s a case of which is better, housing in-calf heifers now and getting the lighter groups of weanlings back out early next spring is my preference as it will drive them on more effectively and they will do a lot less damage than in-calf heifers do at this time of year.
If not already done, now is an ideal time to weigh in-calf heifers and calves to identify animals that are behind target. Housing batches of youngstock for preferential management during the indoor period can be an easy and cheaper option to achieve target weights over the next few months.
Splitting youngstock according to size and weight and feeding meal to lighter bunches is an effective way to get them back on track. Weight gain over the winter on silage varies from 0.4 to 0.7kg/day. Weanlings should be at 40% of their mature liveweight now, or 220kg if the mature liveweight is 550kg. For those at or close to target liveweight now, good quality silage will usually be sufficient to get to target liveweight at breeding without meals.
Lighter calves (>10% below target) will need to be pushed on while they are indoors and turned out earlier to catch up. In addition to good quality silage, lighter calves will need 100kg of a 16% crude protein meal over the next 90 days to bring them back to the average of the group. Weight gains of up to 1kg/day are possible with an early turnout next spring.
In-calf heifers should be approaching 75-80% of mature weight now, or approximately 430kg if the mature weight is 550kg. Smaller in-calf heifers can be given 1-2kg of meal (12-14%CP) between now and early December if they are more than 10% below target weight. Where heifers are below target weight at the point of calving, growth continues during the first lactation at the expense of milk production.
I would caution though about trying to put a lot of weight on in-calf heifers now. Some heifers will put on condition rather than grow from housing to calving so I'd monitor their progress closely. Small heifers laying down fatty tissue as they approach calving can cause more problems in terms of calving difficulty and excessive body condition loss ahead of rebreeding.
The goal is steady, moderate growth and a target Body Condition Score of around 3.0 to 3.5 at calving.
