THE ABILITY to supply the market year-round with fresh lamb, which has reached a killable weight by weaning, would be a financial success story for any farmer.
All-year lambing is yet to be a commercial option for most farmers, but studies into the viability of putting the ram out three times a year suggest the practice will be a future reality.
Year-round lambing was first trialled by Robin Hilson, from the One Stop Ram Shop near Waipukurau, Central Hawke’s Bay, in the early 1990s.
Using Finns and Texels, Robin said that they managed the programme quite well. “We produced lots of extra lambs and speeded up the generation gap, but it was very costly.” The programme required many chemicals and supplementary feed. “It worked, because we got lambs on the ground, but it was very costly. You wouldn’t do it as a commercial venture – it wouldn’t have stacked up at all. “I said, ‘look we’re not going to do this unless we can do it naturally’.”
Peter Kettle is operations manager for the One Stop Ram Shop, and is in charge of the all-year mating system they now run with Dorpers, one of the 12 breeds bred by the One Stop Ram Shop. Peter started mating the Dorpers year-round in 2000.
“We knew that the Dorper had this ability to breed out of season,” Robin said. “All of our previous work had shown that it was very expensive to use any sheep out of season.” The Dorper rams set the ewes cycling naturally, avoiding the need to bring the ewes on artificially.
“We’re getting good conception rates throughout the year,” Peter said. “We’re betting conception rates while the ewes are feeding lambs, and all without the chemicals.” By doing this, he is building up a database of ewes which are lambing consistently every seven months. The lambs they produce must also perform.
“Farmers are wanting to push the boundaries as far as numbers of lambs per ewe and per hectare. I think with traditional breeds, which lamb once a year, you end up with a lot of very small lambs at weaning weight which possibly aren’t marketable.
“Our idea behind the Dorper is that the ewe doesn’t have to rear so many lambs every lambing, but when you combine how many lambings per year, and maybe a moderated lambing percentage, you’re actually weaning marketable lambs every time.”
Running 320 mixed-age ewes and 160 hoggets, they have around 1,500 (all ages plus lambs) in total on the ground.
Every 73 days a flock is going to Dorper rams, so Peter is mating the ewes basically every two months. “The ones that we’ve mated and haven’t conceived, they get exposed to the ram again 73 days later, so that we have some that are lambing every seven months, and some that are mating every nine months, some every 12 months.” He doesn’t select any rams from those that are mating every 12 months, “But they’re part of the mix there for selection.
“I’m basically doing select ewes, to get a handle on the ewes and the bloodlines that are highly fecund, the ewes that are lambing every seven months.” He mates them for two cycles and said not much happens with the first cycle, but the rams actually bring the ewes on and the second cycle is where the activity is.
Every mating, they are picking up those ewes that are receptive to the ram at that time. “That’s the critical point,” Robin said. “If you want to move the lambing date forward – that’s the hardest thing to do in the whole of sheep farming. So if we allow the ram to always get access at a specific date, anything that takes that ram will stay at that lambing point.
“Anything that doesn’t and goes back moves into another mating, but the whole time we’re breeding them through and making them naturally mate. That’s why we’re at a point where we say we can mate all year round sustainably.”
| Birth Date | Weaning Date | Age (Days) | Weaning Weight | Growth gms/day |
| 01-05-05 | 05-09-05 | 96 | 33.9 | 311 |
| 25-08-05 | 04-12-05 | 101 | 36.5 | 322 |
| 04-11-05 | 10-02-06 | 98 | 35.1 | 317 |
| 17-01-06 | 10-04-06 | 83 | 25.2 | 255 x# |
| 03-04-06 | 25-07-06 | 113 | 28.4 | 216 |
| 12-06-06 | 12-09-06 | 92 | 24.3 | 221 ## |
| 25-08-06 | 06-12-06 | 103 | 34.3 | 294 xx |
| x- These ewes lambed 120%; re-mated after 16 weeks #- All lactating ewes suffered ryegrass staggers ##- Cold, wet conditions xx- Same ewes as X, 160% tailed | Ewes are lambing 1.7 times per yearAll lambs were killable at weaning on four occasions. For three lambings the weather was wet and atrocious. Figures are averages. Weights are kg’s. Birth weight average 4kg. |
-RURAL CENTRAL DISTRICTS • October 2007