Ewe health key to lamb survival

The age old challenge in pastoral farming is to manage the feed supply, animal demand equation, and this article asks whether sheep farmers are using the tools available to do this.

It has often been said that most new technology in the sheep industry comes via their dairy cousins and Julie Everett Hincks suggests farmers should feed their ewes like dairy cows, use BCS like they commonly do in that industry, and carefully look at the stocking rate used, and date of lambing.

With many farms putting up with a big wasteage of lambs at birth the economics of better survival makes profitable reading.

Will future sheep management involve weekly paddock measurements, regular BCS scoring and lambing dates that better match the spring growth?

Although I often noted the last lambs born were never the last lambs off to the works, the dilemma often was at mating. Later lambing meant later mating, not always easy to keep ewe bodyweight steady at joining when late autumn conditions are unfavourable.

The woman expertly wielding the knife and batting away the good-natured banter was Julie Everett-Hincks, a leading scientist from Invermay Agricultural Centre near Dunedin, who has done countless dissections as part of her long-running research into improving lamb survival rates.As lambing starts in earnest in Nelson, it's a subject uppermost in many farmers' minds, especially with lambs fetching record prices reports The Nelson Mail.

Dr Everett-Hincks had earlier told the 25 farmers gathered for the seminar organised by Beef + Lamb New Zealand that a typical farmer with 2000 breeding ewes could earn another $6500 if they could reduce their lamb losses by 2 per cent and another $16,000 with a 5 per cent fall. Nationally, the sheep industry would earn an extra $79 million by saving 2 per cent more lambs and a whopping $200m if that figure rose to 5 per cent.

Her research shows that most lambs die within three days of birth – they are either stillborn, don't survive a difficult or prolonged birth or succumb to starvation exposure. A small proportion are aborted before birth. On the well-managed farms she studied, 11 per cent of lambs didn't make it through to weaning, whereas the national average is closer to 25 per cent, suggesting there is plenty of room for improvement. A lamb, she said, had a far higher chance of living and doing well if it had a birth weight of around 5kg, although just getting it up from 3kg to 4kg would boost survival rates by 10 per cent and a farmer's income by $30,000.

Birth rates can by boosted through genetics by breeding from rams with better production values or by improving the way ewes are managed and fed.Ewes in better condition throughout their pregnancy produced more live and heavier lambs and were better mothers as they were healthier, more attentive and less likely to wander off to graze. However, Dr Everett-Hincks said many farmers don't feed their ewes well enough from mating through to weaning and therefore were missing out on getting the best out of them, adding they could learn a lot from the way the dairy industry looked after cows during this period.

She advocated they adopt body condition scoring (BCS) as a hands-on way of monitoring a ewe's progress. Essentially, it meant getting all ewes in the yards and feeling along their backs. If they had corrugations, then the ewe was too skinny and needed more feeding.She recommended this be done four times – at mating, when they are pregnancy scanned, when they get their pre-lambing vaccination and when the lambs are weaned. Ewes with low BCS should be put in a separate mob and fed more.

However, she said what tended to happen was that ewes tended to lose condition from mating through to weaning which was surprising given that was when spring pasture growth and quality was at its best.It suggested farmers were either running too many ewes to the hectare or were lambing at the wrong time, Dr Everett-Hincks said, challenging the farmers present to review what they did.

The same volume of lamb could be produced from a slightly smaller, better managed flock and with prices high farmers would still be better off, she said. Rather than sticking to the same old lambing date, farmers needed to ask themselves whether it coincided with optimum pasture growth. Her comments drew plenty of questions and some scepticism, with some farmers concerned that ewes would be too heavy or unfit at the weights she was suggesting and others voicing doubts about whether they could grow enough grass to feed them the recommended intakes.

The key was feed budgeting, but few farmers had a good understanding of typical monthly pasture growth rates on their properties or knew how to measure it. "It requires some technical skill, but unfortunately most farmers don't have that. It enabled farmers to plan ahead and if they were going to be short of grass then to make early decisions on when it was best to sell their lambs, he said.At present, many relied on "seat-of-the-pants farming" based on their experience over the years, but this reactive rather than proactive management approach delivered lower returns.