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Sunday 23 July 2017

Weight gain of 210g/day at Lyons

Sheep

Dr Tommy Boland

We have just drafted 73 lambs averaging 45.5 kg liveweight, which have grown at 210g/day since our last draft. This growth rate comes despite the slowdown in grass growth to 30-31kg DM/ha/day over the past two weeks. This is almost half of what I recorded last month.

There is still a good supply of good quality grass ahead of the lambs but to maintain supply, one bag of CAN/ac will be blanket spread this week. As part of our data collection for teaching and research purposes, we weigh the lambs on a fortnightly basis.

For the first two weeks of the past month, growth rate was down to around 150g/hd/day. This occurred after the lambs spent a week in one particular paddock where they were uneasy and, despite good grass supply, they spent a disproportionate amount of time grazing along by the ditches. We don't have an explanation for this but Stephen, our shepherd, was able to tell me that it was similar last year.

However, it didn't coincide with a weighing on that occasion so we weren't able to pick up the growth rate effect. This time, it has given us enough reason to earmark that paddock for reseeding, with a view to increasing performance next year.

Calibrate

The issue of checking the weighing scales also reared its head for us recently. We use electronic scales and calibrate it frequently. This month we found a disparity of up to 3kg between the same lambs which we weighed twice in the space of a couple of hours. This 3kg difference could translate into almost €7/hd when lambs are sold. This problem was easily solved but it does highlight the importance of checking your scales regularly.

We set 35ac of rape on August 17 to carry the ewes during late November and December prior to housing. This was sown after winter wheat. Half the area received 2,000ga of cattle slurry per acre, with the remaining area getting slurry once the crop has established. The entire area was disc-harrowed and then the seed was broadcast at 4kg/ac using the quad and slug pellet applicator. To finish the job off, the area was rolled.

The ewes have been separated into two groups. Like many farms at this time of year, we put those in good condition in one group and the thin and lame ewes in a separate one. The latter group is getting priority access to the best quality grass, and the benefits of flushing ewes in poor body condition in terms of increased ovulation rate and litter size are widely known at this stage.


We do have an issue with contagious ovine digital dermatitis (CODD) on the farm and this does not respond to the traditional footbathing solutions, so special consideration is required. CODD is a particularly virulent and nasty condition that will spread rapidly if not identified and treated correctly.

The initial sign of the disease is an ulcer at the coronary band where the horn joins the skin, and the entire horn can be shed if not treated. This obviously causes severe pain for the animal and will greatly reduce performance if left unchecked.

A single claw may only be affected but, in many cases, more than one foot is affected. Ewes and lambs alike can be involved. There is a concerted effort to sort out this problem now before mating as we don't want to disturb the ewes in the first month afterwards, where stress can reduce litter size.

Last week, John Large highlighted the importance of having rams fit for the breeding season. He's absolutely right, with the aim on this farm to have a body condition score (BCS) of 3.5-4 on our rams at mating to ensure that, rather than eating, they focus on the task at hand, so to speak, when introduced to the ewes.

This takes its toll on the rams themselves, with some losing up to half a BCS a week during mating. This is partly why over-reliance on ram lambs should be avoided. Ram lambs should only be expected to mate around 30 ewes, which is half the number a mature ram can handle. Whatever you do, don't rely solely on ram lambs. A lack of experience is not always compensated for by youthful enthusiasm.

Dr Tommy Boland is a lecturer in sheep production at Lyons Research Farm in UCD. Email: tommy.boland@ucd.ie

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