The research, focused on reducing GHG emissions of New Zealand beef through better integration of dairy and beef production, suggests the beef sector stands to shave off 22% of its annual GHG production.
This would involve dairy-beef calves completely replacing beef breeding cow calf production.
The report authors, who included Dr Stu Ledgard of AgResearch, also suggested dairying’s social licence to operate would also improve by replacing bobby calf slaughter with dairy-beef calves for rearing.
The report authors acknowledged in practice, a 100% reduction in beef breeding cow numbers would be unrealistic because some beef bulls would always be needed to inseminate the dairy herd.
The ratios of bulls to steers to heifers slaughtered was not changed, but it was also acknowledged running more bulls could achieve even greater reductions, due to more rapid growth rates.
They also assumed pasture suitable for finishing traditional beef animals could be used for finishing dairy-beef animals, while some of the pasture currently used by breeding cows would also be used to finish the dairy beef animals.
But sheep and beef farmer and former Beef + Lamb NZ (B+LNZ) chair James Parsons, who has just made the move back to breeding cows on his hilly Northland property, has defended the role the animals play on many steeper North Island properties.
“Breeding cows will always metabolise a lot of feed that is not always the best quality,” he said.
“You would want to know with the work, have they focused enough on what the breeding cows contribute?
“On hill country she will groom feed before other stock comes in. We had been using dairy bull beef on our farm on the steep hill country to do the similar job.
“But we are eating more grass across the entire farm with the breeding cows there now, not wasting as much. They are making it possible for the rest of the stock to eat better pasture too.”
He argued for much of NZ’s hill country, the breeding cow still performs a vital role and actually helped reduce gas emissions by ensuring other stock had higher quality feed in their wake, making for quicker finishing times.
AgFirst consultant and long-time beef advisor Bob Thomson says it paid to consider the beef cow’s contribution to the entire farm system, rather than just her economic value.
“The basis of any of these sorts of arguments, in simple terms, is predicated on increasing the efficiency of production, as each tonne of pasture eaten equates to the same amount of methane production,” he said.
“The article has merit in addressing the GHG efficiency argument.
“However, it is somewhat academic, having no consideration of the pasture grooming role breeding cows afford on our extensive sheep and beef farms.”
He says if nothing else, the research paper prompts the question about what alternative stock classes there are for farmers to opt for today.
“I always ask farmers, ‘how many (breeding cows) do you really need?’” he said,
“The next question is ‘what is a good alternative if you didn’t use them?’”
An argument often put up by farmers is that dairy-beef genetics cannot match the robustness of breeding cows.
But he says in some cases this was not true. He pointed to good genetic options being revealed in the B+LNZ dairy-beef progeny trials that provided data on win-win options for both dairy farmers and their beef farmer clients.
“This includes short gestation, low birth weight animals that are also high growth, and easy finishing with good marbling. It’s a trick quite a few people are missing,” he said.
Thomson conceded that on some farms there was an environmental case for looking at breeding cow alternatives.
“Overall, beef breeding cows have gotten much bigger, by about 100kg over my time. When big cows are farmed in steeper country, with inevitable soil disturbance coupled with heavy rain events, you definitely risk losing soil and your phosphate into waterways,” he said.
Thomson says the research was also too simplistic by addressing just GHGs.
It failed to consider other negative environmental impacts, such as the encroachment of dairy cows onto areas where nitrogen leaching has a negative impact.
The research authors also noted the “social licence to operate” for the dairy sector would be extended if dairy-beef replaced bobby calf slaughter.
He says that issue was a burning bridge for the sector, but also one that perhaps should be the responsibility of the dairy sector.
He suggested that if you were to take a holistic view, consideration may need to be that one million less dairy cows, rather than one million less breeding cows, was the solution.
“The question that needs addressing is, where will the one million surplus bobby calves be farmed if they are reared and finished? GHG’s are just one of the considerations,” he said.
Agricultural economist Phil Journeaux says if nothing else, the research raised an important issue facing the dairy sector, which may only have a decade before killing bobby calves was no longer acceptable.