A trial of some 300 calves on three separate farms in the Clutha district last spring achieved huge progress in developing an understanding of the effects of a probiotic supplement on the weight gain of neo-natal calves according to a report just released by the Clutha Agricultural Development Board.

The report indicates that the fresh probiotic supplement improved the weight gain of treated calves by averages of 18 grams, 39 grams and 59 grams per day respectively on the three farms.

The three farms all had different calving procedures, meal intakes and rearing conditions, and the impact of the treatment was shown to vary considerably from farm to farm.  The report concludes that these variable results are not surprising and aligns with previous scientific knowledge that the particular farming system is a hugely important determinant of the effectiveness of probiotic supplementation.

The report claims that this was possibly the largest calf trial in New Zealand-style grassland farming situations ever undertaken internationally.

“The trial group aimed to collect a large amount of reliable data to set against local anecdotal information and the suggestions in the literature that probiotics have a positive effect on animal growth rates and we believe we have done this,” said project manager and the report’s author Malcolm Deverson from the Ag. Board.

“Where the probiotic supplement worked, it really seemed to work well. Of course we really don’t know why and how it had the weight gain effect that we observed from the raw data. And there’d have to be more trials to establish a definite link.”

The report suggests that farmers may get the most benefit from the microorganisms in probiotics when animals are under some stress – for instance when they are moved from rearing pen to grass, and also during periods of bad weather.

“I doubt if it’s just accidental that the one farm where the supplement appeared to have the least effect was the one farm which kept their calves in their warm and sheltered rearing shed with no grass for the whole seven weeks of the trial,” said Mr Deverson.

The report explains further trial work that the project group would like to undertake, including trying to find out under what farming circumstances probiotics work best, whether there are other health benefits, whether probiotics effects calf survival, whether feed efficiency is improved and whether this varies by calf weight class at birth.

“The statisticians had a field day with all this data,” said Mr Deverson, “and surprisingly enough they didn’t all agree.  I hope we have provided them with a lot to think about. Farmers are being told that they need to produce more from the same environmental footprint, so anything that could give even a marginal edge in production should be investigated further.”