Lambs weaned three weeks ahead of schedule as drought kicks in

Lambs at Lyons Farm were weaned last week at an average age of 81 days or just over 11 weeks. This is approximately three weeks earlier than normal for us the decision to wean was precipitated by poor grass supply arising from a severe soil moisture deficit.

As of May 28, the soil moisture deficit at Lyons was 70mm. To put some context on this, the peak soil moisture deficit encountered at Lyons in 2018 was just over 100mm, so things are dry.

Dr Conor Murphy of Maynooth University says April and May of 2020 were the driest on record at Phoenix Park, confirming for many of us the unusual conditions we are presented with this year.

On average we receive 111 mm of rain in April and May combined. This year we received just 30 mm.

The decision to wean the lambs at an earlier stage was based on the prioritisation of grass resources on the farm.

Much of our sheep-grazing ground is heavily impacted in dry conditions due to its shallow soil depth. This ground is predominantly on the hill at Lyons and with silage already harvested and slow to recover, grass ahead was low.

By weaning lambs, ewes’ demand for grass is reduced by 60pc and we can use the ewes to clean out paddocks after lambs have grazed them. This helps to retain sward quality, and it also allows lambs some choice, which will hopefully maintain their performance.

The average weaning weight was 31.5kg, with an average growth rate from birth of 320 grams per day.

The single-born lambs averaged 33.6kg, the twins 31.6kg and the triplets 30.4kg. We would be happy with these weaning weights at our conventional 14-week weaning timepoint and it reflects the good conditions these ewes and lambs have had since turnout.

Optimising

It also reflects a focus on breeding, feeding and management within the flock over the past three years as we have placed a heavy emphasis on optimising the number of lambs born and weaned and finishing these lambs predominantly from forage.

There are a few key aspects to this, starting with pregnancy nutrition and management, followed by achievement of good lamb birthweights and ewes lambing down in correct body condition.

This allows good lamb performance post-turnout once grass quality and quantity are appropriate. All these factors came together this year, but that doesn’t always happen, as we learned last year, when a cryptosporidium outbreak had a negative impact on lamb performance and survival.

We have some Redstart sown for lambs, but this has suffered in the recent dry conditions. One paddock has germinated well and has shown some growth but is nowhere close to where it should be in a ‘normal’ rainfall year. The second paddock has not really germinated yet.

So, for the time being the focus will be on keeping good-quality grass ahead of the lambs and selecting animals as soon as they become ready for the factory.

We have had minimal lameness issues this year since turnout, which was a relief as we had some issues with CODD and joint ill in ewes and lambs respectively around lambing.

We will body-condition-score all ewes on Thursday. We were unable to do this at the time of weaning due to restrictions in place as a result of Covid-19 work policies.

The ewes are recently shorn and from observing them they appear to have maintained their condition reasonably well, but there is absolutely no substitute for putting your hand on the animals.

The next few weeks will involve drafting lambs as they become fit, all ewes will have their udders checked at three weeks post-weaning for any mastitis or abnormalities, and plans for sourcing replacements will be formed in light of the somewhat more limited sales options likely in July and August of this year.

Professor Tommy Boland is a lecturer in sheep production at Lyons Farm, UCD. @Pallastb tommy.boland@ucd.ie