In a Beef + Lamb New Zealand podcast Massey University’s Dr Paul Kenyon describes how ram harnesses can be used to identify ewe lambs that ovulate early in flocks where hogget lambing is not practiced.
Studies have shown that these early-cycling animals will be more fertile and fecund during their lifetime.
“There is a genetic link there.”
In a bid to increase the productivity of their ewe flock, some farmers are keeping more ewe lambs back than they need as replacements, then running a harnessed teaser (vasectomised) ram with them in late April and May.
The marked lambs are retained as replacements as these are likely to be the most fertile as adult ewes.
“It’s an early screening tool and it does work.”
In mixed-age ewes, ram harnesses give farmers the ability to identify ewes that have been mated and put them back onto maintenance rations – with a back-up ram.
Through involvement in a Red Meat Profit Partnership programme, the Hodgen family, who farm in North Canterbury, found the use of ram harnesses has thrown some surprising results. They discovered 93% of the ewes were mated in their first cycle and so could be put straight back onto maintenance feed with a follow-up ram.
“It’s phenomenal how much feed we have saved for the price of ram harness and crayon,” says Dan Hodgen.
The ewes remain marked and at set-stocking were run in mobs according to their mating dates. This meant the family was not set-stocking earlier than they needed to and management over lambing was much more targeted.
Canterbury-based farm consultant Wayne Allan says there are pluses and minuses to using ram harnesses – but they can provide valuable information that can help in the allocation of feed resources and management around mating and lambing.
He says today’s ewes tend to be heavier and more fecund, so a higher proportion of the flock can be mated within the first cycle (80 -90%). If marked, these ewes can be put back onto maintenance – although Allan cautions against under-feeding ewes at this stage.
At lambing, the marked ewes can then be managed according to their lambing date, so later-lambing ewes can be set-stocked later which again provides an opportunity to be more strategic with feed resources.
Allan points out that foetal aging at scanning does provide this same information, but it is slightly more expensive and doesn’t allow for feed management over mating.
He says the downside of ram harnesses is the work involved in changing crayons and, on properties with a lot of scrub, there is always a danger of the harnessed ram getting caught up, or losing crayons.
On larger, extensive, properties with large numbers of rams, the logistics of finding rams and changing crayons can make them a less impractical option.
Where the focus is on determining when rather than whether the ewes have been mated, Allan suggests not putting the harnesses on until 10 – 17 days into mating. This reduces the workload and means unmarked ewes will be early lambing or are dry.