A pilot study into whether the hormone prolactin affects the mothering ability of a beef cow could have major impact for cattle on northern Australia properties.
Charles Sturt University Masters student and veterinarian, Dr Rory Nevard said mothering ability is crucial to the breeder cow, and we need more information about the factors involved.
“In northern Australia, successful calving and calf survival are important for productivity, profitability and animal welfare,” he said.
Calf wastage and deaths are estimated to cost Australian graziers around $54 million each year.
However, calf wastage is difficult to assess in the large scattered herds across northern Australia as herds there are only mustered once or twice a year.
Previous research in the US and Europe has shown major calf losses are in first few days of life, particularly due to poor mothering behaviour.
Dr Nevard said Australia we know little about our cows’ mothering ability.
“Work in other species has shown that high levels of the hormone prolactin may be a crucial factor in becoming a good mother, but this is yet to be shown in cattle,” he said.
“It we find this relationship between prolactin and mothering ability in cows, it may offer important opportunities for cattle breeding or provide producers with management options.
Prolactin hormone is secreted from the brain and is important for both lactation and maternal behaviour.
“We know prolactin helps cows release their milk after calving. What we don’t fully understand is if prolactin is also related to the cow’s mothering ability – its ability to look after and care for its calf,” Dr Nevard said.
“In rats, rabbits and humans, this ability to produce prolactin can be ‘programmed’ into the foetus in late pregnancy, and so can be inherited from mother. We don’t yet know if this happens in livestock.”
Dr Nevard and his supervisors are currently running a pilot project to assess the technologies and techniques to be used in a wider project.
They are working with the Precision Livestock Management Group from Central Queensland University in Rockhampton, who successfully use UHF proximity loggers to record and measure animal behaviour patterns in cattle in the tropics.
“In my current project at Charles Sturt University in Wagga Wagga, we are measuring prolactin levels in the blood of 30 pregnant Angus cows every two days for three weeks, before and after calving,” Dr Nevard said.
“As new calves are born, we are also fitting proximity logger collars on both the cow and calf to record the interactions between them.
“This initial study gives us baseline data we need to check if this system would work in a bigger field trial up North. This will be needed as it is too difficult to use findings from Bos taurus cattle in southern Australia and expect them to be the same in North Australia, particularly where we use cattle with Bos indicus breeding.”
Dr Nevard is excited with the possibilities of this work.
“If there is a direct relationship between prolactin and mothering, we can then ask the question, ‘Can we select cows for prolactin production to also be better mothers?’” he said.
This has important implications for cattle breeding and the big cattle stations of northern Australia where cows are left to calve and raise their offspring with minimal human intervention.
“Cows selected and bred for better mothering means these producers could help reduce some of the economic losses that occur between pregnancy testing and calf weaning,” Dr Nevard said.
“We know a good mother depends on more than prolactin: it also depends on cattle breed, climate, and the production system used.
“But breeding better mothers could give their calves a better chance to get on their feet and face the challenges of harsh climates or poor-quality feed.”
This research is supervised by Dr Cyril Stephen, Associate Professor Scott Norman and Dr Sam Pant, and funded by Meat & Livestock Australia.