Pilot trial records nearly 5kg greater liveweight gain in Vitalise ewes

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An on-farm pilot trial investigating calcium and magnesium supplementation in late-pregnancy and lactating ewes has recorded encouraging results, with ewes offered Vitalise gaining 4.8kg more liveweight than the control group from pre-lambing to weaning.

Vitalise is a pelletised mineral supplement produced by CP Lime and originally developed for dairy cattle. The formulation used in the pilot supplied calcium, magnesium, phosphorus and trace elements.

The pilot trial, conducted by Dr Samuel Dennis at Isherwood Research Station, Glenroy, was designed to explore the potential role of mineral supplementation during a period of high nutritional demand.

Lighter twin-bearing ewes were deliberately selected for the pilot, with one group offered Vitalise from one month before lambing and a control group not offered Vitalise.

At the beginning of the trial, the groups were almost identical in weight, averaging 58.9kg in the control group and 58.8kg in the Vitalise group.

By weaning, control ewes averaged 62kg, while Vitalise ewes averaged 66.7kg. Overall, the control ewes gained 3.1kg compared with 7.9kg for the Vitalise ewes.

“The control ewes had put on 3.1 kilograms, and the Vitalise ewes had put on 7.9 kilograms, almost five kilograms more than the control ewes,” Dennis said.

“This was a dramatic difference. They were in much better order.”

Lamb growth was essentially the same between the groups, with mean weaning weights of 27kg in the control group and 27.2kg in the Vitalise group.

Dennis interpreted the comparable lamb growth alongside the difference in ewe condition as an indication that the control ewes had drawn more heavily on their own nutrient reserves during lactation.

He also observed differences in ewe vigour during the pilot. Some control ewes were reluctant to move with the flock, while the Vitalise ewes generally appeared more active.

Blood samples taken from five ewes in each group at tailing indicated higher magnesium concentrations among the Vitalise ewes, while calcium levels were similar between the groups.

Dennis had also introduced Vitalise to his wider ewe flock about a month before lambing, when signs consistent with calcium deficiency had begun to appear. He observed no further hypocalcaemia symptoms in the main flock from that point until lambing.

While the pilot did not provide sufficient data to quantify any effect on ewe mortality, Dennis said the results around ewe condition were particularly encouraging.

“Better condition at weaning means the ewes go into summer in good condition and only need to be maintained through to mating,” he said.

“Poor condition at weaning means condition must be gained somehow over summer, on lower quality feed, and may not be possible due to drought. Anything that allows ewes to gain condition over spring helps to match feed demand to supply and to the environment.”

Dennis said the economics also looked encouraging.

Recorded Vitalise usage over the 119-day ewe trial averaged about 0.41kg per ewe and her lambs, including any spillage. Dennis suggested farmers could budget on around half a kilogram per ewe over spring.

“If that half a kilogram of Vitalise can result in almost a five kilogram increase in ewe liveweight at weaning, the economics of it stack up very well,” he said.

Dennis believes flocks where calcium or magnesium deficiency is suspected, including those experiencing metabolic health issues or below-desired performance, are likely to benefit most.

At the end of the pilot, previously untreated control ewes consumed Vitalise when it was offered, while the supplemented group showed little interest. Dennis believes this may reflect differences in mineral need.

The pilot found no measurable improvement in growth from feeding Vitalise directly to weaned lambs and did not continue long enough to determine whether better ewe condition would translate into improved reproductive performance at the following mating.

Dennis said the results were encouraging enough for him to continue using the product in his own flock.

“I’m very impressed with this product. I think it made a major difference to my ewes this spring and the trial results bear that out,” he said.

“This is a product that I am incorporating into my own management and will be using every year.”