How many lambs are your rams siring?

Spotlight on potent rams sees large variation in lambs sired

The potency of rams is being looked at in more depth, not as a core part of the MLP project but as an interesting add on. Photo: Emma Grabham

The potency of rams is being looked at in more depth, not as a core part of the MLP project but as an interesting add on. Photo: Emma Grabham


Libido, maturity, semen quality even social dominance could be causing large differences in how many lambs a ram sires.


Ever wondered how many lambs each of the rams in a paddock were siring?

The New England Merino Lifetime Productivity (MLP) Project site has noted a large variation in the number of lambs produced by each of the individuals rams in their sire battery.

Australian Merino Sire Evaluation Association (AMSEA) executive officer Ben Swain, Gunnedah, said last year at the New England MLP site 712 of the 2017-drop ewes were joined to 16 rams naturally out in the paddock, which generated 709 lambs that were DNA pedigreed to their sires.

"Those 16 sires produced anywhere from three lambs to 97 lambs - a huge variation," Mr Swain said.

"The guy producing 97 lambs is the one you want in your ram battery."

While it is unknown what is behind this large difference, Mr Swain said libido, maturity, semen quality even social dominance could come into play.

"We don't know (the cause) ... the rams joined were all similar in age, and joined under the same conditions," he said.

At the Macquarie MLP site at Trangie, and Balmoral MLP site in western Victoria, the potency of rams is being looked at in more depth, not as a core part of the MLP project but because it is an interesting add on.

"We've done a lot of semen testing on rams, libido testing and structural assessment before they join, and really at the moment there is not a pattern," Mr Swain said.

"Rams with low semen morphology don't necessarily produce the least amount of lambs.

"There is a ram at Balmoral that, across the three drops, has produced the most amount of lambs. But when you look at the semen quality it is average/just like all the others. But he always is fat, and doesn't come out poor.

"Some rams serve ewes, and they get in lamb straight away, others it may take three times, they get knocked up so they may be serving less.

"There doesn't seem to be one test you can do on rams to tell if they will get any lambs or not."

Social dominance could also come into it, according to Mr Swain. As a commercial producer himself, Mr Swain said he has 50 rams running around, and 10 could be producing no lambs.

"We are now out choosing rams on ASBVs (Australian Sheep Breeding Values). We might pay more for a better ASBV rams that will make more genetic improvement in our flock, but if you are not going to get any lambs by that ram you aren't gaining anything," he said.

"(Identifying high potent rams) is not about running less, but so you can choose the more proactive rams on performance and productivity of getting lambs."

Very little testing and research has been done in sheep in regards to serving capacity and semen quality, with a lot more work needed to be done in that area to answer the questions surrounding the variations.

The New England site located at the CSIRO's Chiswick farm near Uralla is the youngest of the five trial sites in the MLP project.

Last year was the first year of reproduction there, so results cannot be compared to previous years Mr Swain said.

"The maiden ewes lambed 103pc, and weaned at 85pc, which is good in the year they had," Mr Swain said.

Wool cut in the 2017-drop was on average 4.6kg per ewe as an adult, three-year-old.

"This is down a bit from 4.9kg as a two-year-old, which is a result of reproduction," he said.

"What we are interested in is those sire groups that can do both; rear heaps of lambs and maintain fleece weights.

"There is variation in sires, some rear heaps but trade it off in wool - the middle is what we are looking for; those that can rare above average number of lambs, and produce a good amount of wool."

This year the field day moved online with viewers from across Australia and the United Kingdom and New Zealand.


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