Southern Mulit-breed Project set to offer insight into more heritable fertility traits

Genetics rather than management play just as big a role, according to Dr Brad Walmsley of NSW DPI.

For the first time Brahman cattle will be put head-to-head with Angus, Charolais, Hereford, Shorthorn and Wagyu cattle to establish genetic analysis across all breeds as part of the Southern Mulit-breed Project.

Responding to an earlier comment at the North West Beef Producers Forum that fertility was only an issue in the country's north, Dr Walmsley argued southern breeds were just as susceptible to the same scrutiny but until now their environment hadn't challenged them.

"There is actual genetic potential in southern breeds for fertility it's just that we have never tested it because our environmental conditions have been too good and as climate change is moving and moving us into more challenging environments this sort of stuff is going to be exposed," Dr Walmsleysaid.

"It's the basis of the repronomics project in the north where they can demonstrate vast difference in fertility across the breeds and within the breeds and I think we are going to start to see that as the environment starts to become more challenging."

Fertility is a key part of the analysis work being undertaken in the multi-breed genomic evaluation project aimed at delivering comparative estimated breeding values for the country's six leading breeds.

Last year 1729 cows were joined with 1303 calves set to be weaned this year and 1535 cows pregnancy tested this year.

Everything from growth, reproduction and carcase traits will be recorded but new traits like resilience, calf vigour, adaption and methane will be analysed along with an animal's horn/poll set.

The project will also look at establishing new traits such as age at puberty and first lactation anoestrous, both of which have much high heritability than the current days to calving breeding value used within Breedplan that currently sits at about 10 per cent.

"The first two we are going to look at is age at puberty and first lactation at anoestrous and that trait is how long it takes the cow to get in calf after she has had her first calf," Dr Walmsley said.

"That's some thing we hear back all the time and something I experience at home on the family's property that these first calf cows tend to have the toughest time getting back in calf after they have had that first calf.

"The critical thing is we are going to do it in the same environment so those females are always exposed to exactly the same management.

"The heritability of (age at puberty) in a heifer is 40 per cent. The heritability of first lactation at anoestrous is 55 per cent so more than 50 per cent of the difference of getting back in calf after that first calf is due to genetics and we are going to be looking at that and feeding that into Breedplan to move our fertility traits into the more easily selected traits."

Cow composition or body condition scores will also be refined, opting to scan for eye muscle area, fat and visual appraisal at mating rather than the conventional weaning timeframe.

"The reason is that represents the point in her lifetime where she is under the greatest nutritional challenge; she has just had a calf, she is trying to retract her uterus, she is lactating and she is supposed to go back in calf all at once," he said.

It is hoped the project will eventually help achieve a new index that reflects future profit drivers across the six different breeds.

"There are bulls in each breed that are good and there are bulls in each breed that are bad," Dr Walmsley said.

"That's one of the things that's the problem with our industry; we have aligned it that there is one breed that is good and another breed is not...it's the individuals we measure that matter, not the breed."