In any breeding herd or flock, the timing of weaning is a major determinant of profit. Weaning is our major tool to maintain body condition score (BCS) on our females. Our goal is to have cows in BCS 3+ at calving and ewes BCS 3+ at lambing and joining. If we wean too late and can’t pick them back up to BCS 3+ before calving/lambing on our pastures then we either will see lower re-conception rates, or need to look at feeding them to regain condition.
Key Point #1. Weaning is a driver of re-conception rates.
If we need to feed them, then that will cost money, so costings will need to be done. We also need to look at the Standard Animal Unit (SAU) ratings for the animals. If you look in any RCS manual, you’ll find the Large Stock Unit (LSU) and Dry Sheep Equivalent (DSE). In simple terms, the bigger the animal, the bigger their maintenance requirements. Nutrient intake above maintenance requirements goes into production (what we get paid for). Therefore, it is more economic to feed a small weaner than to feed a cow or ewe. The weaner will have much lower maintenance requirements and therefore will use less feed for maintenance and put more nutrition into production. A cow or ewe will need a lot of nutrition to gain a BCS.
Key Point #2. It is more profitable to feed a weaner than a cow/ewe.
Possibly the biggest consideration at the moment is the impact on stocking rates. Most of Australia is looking down the barrel of a very ordinary growing season. If you calve/lamb in Spring/Summer then weaning could halve your stocking rate. Look at the LSU/DSE tables in your RCS manual to see the impact for your herd or flock. (Don’t use yearly averages or lump weaners into one number as some places suggest, you’ll get a rude shock in reality!)
Cattle weaning example (using LSU):
If you have a 450kg lactating cow, her rating is 2.14 LSU/cow calf combination. A dry (weaned) 450kg cow is rated at 0.99 LSU/hd. That is a reduction of 1.15 LSU or 53.7% in feed demand. Ask any producer who rotates breeding animals for their observations in how much less they eat after weaning (and how much more they eat after calving/lambing). If you sell the weaner or put in on a full ration then this more than halves your stocking rate. If your carrying capacity is limited this year, this makes a huge difference. If you have the feed available and decide to keep the calf, then a 150kg weaner putting on 0.25kg/hd/day* would have a rating of 0.48 LSU/hd. So, the dry cow and weaner would have a total LSU value of 1.47 (0.99 + 0.48). This is still a reduction in stocking rate of 0.67 LSU per cow/calf combination (a 31% reduction in stocking rate).
*I’m assuming if you need to early wean the potential daily gains will be limited. Do the numbers on your circumstances for accuracy when making a decision.
Sheep weaning example (using DSE):
If you have a flock of 50kg lactating merino ewes (with 25% twins), their average DSE rating would be 2.71 DSE/ewe lamb combination. Weaning them would leave you with a ewe rated at 1.0 DSE/hd. Again, if you sold/fed the weaners that is a massive 63% reduction in stocking rate. If you grazed the weaners at 15kg gaining 100g/hd/day on grass then they would be 0.64 DSE/hd. After adjusting for 25% twins, this is still a stocking rate reduction of 34% purely from weaning.
Key Point #3. Weaning breeders is the biggest ‘lever’ you can pull to reduce stocking rate.
If you are early weaning cattle then you might find this reference document on handling and feeding weaners useful. Please note, we recommend you develop strategies specific to your own circumstances with support from advisors. Call the RCS office or your RCS advisor for more information on how to arrange some one on one support.
The best way to get a firm understanding of these topics (BCS, reproduction, economics of feeding), is to get to a Grazing for Profit or Farming & Grazing for Profit School. Check out where our schools are scheduled for the rest of this year here.
David McLean, RCS Chairman.