Breeding in the Teagasc Athenry demo flocks began on Friday 10 October with excellent progress to date. Flock researcher Philip Creighton reported approximately 80% to 90% of ewes mated within the first two weeks of breeding, with all ewes now served once.

If the majority of ewes keep to their first service, which is likely to be the case given the favourable breeding conditions, the flock will be on course to repeat its very compact lambing with 85% of ewes lambed within 17 days in spring 2014.

The compact nature of lambing is influencing decisions currently being taken. For a start, the breeding date was delayed by one week this autumn, with ewes forecast to start lambing from 6 March 2015.

Philip said that delaying the lambing date by one week will hopefully better match grass growth.

“With a very compact lambing, we had a rapid increase in feed demand at the end of March. We found it hard to cope with grass demand, with lambed ewes quickly eating into grass grown during the closed period and March growth rates failing to maintain sufficient grass ahead of ewes.

“Delaying lambing by one week will hopefully better help to bridge the gap in grass demand until grass growth increases sufficiently to meet flock demand.”

Grassland management

Delaying lambing by one week is only one aspect of aiming to have sufficient grass supplies next spring. The focus at present is to balance autumn grass supplies to maximise the length of the grazing season for ewes, finish remaining lambs and get paddocks grazed and closed for early spring grazing.

The first paddocks targeted for early spring grazing have been closed in the last week to 10 days.

The target is to give these areas a rest period of at least 120 days to ensure maximum grass supplies build over the winter and early spring.

Current grass supplies vary significantly between the six flocks. The medium and high prolificacy flocks stocked at 14 ewes per hectare are coming under the most pressure for grass, with 16 and 20 days grazing, respectively, ahead of ewes.

With grass growth rates falling to 30kg DM/ha and 25kg DM/ha in the last two weeks, these flocks are now eating into their reserve of grass accumulated for winter grazing, with a demand of 45kg DM/ha.

Demand is running ahead of the other flocks due to more than 30% of lambs remaining in these respective groups.

Philip explained that steps have been taken to prolong the grazing season.

A lot of lambs remaining in these groups are currently weighing about 43kg to 44kg. Another 42 lambs were drafted across all groups this week (including 20 lambs or 10% of high stocking rate (HSR) groups). The aim would be to do the same next week and then house the remaining lambs (hopefully 15% to 20% or 35 lambs) in the HSR groups and finish indoors on silage and meals.

These lambs are currently grazing ahead of ewes, with ewe grass demand dictating the length of time spent in paddocks.

Meal supplementation was also introduced 10 days ago at 200g to 300g per head per day and has been increased to 500g per head per day to boost performance and try to push as many lambs through the system as possible before housing.

The farm is being walked again this week and, depending on growth rates, lambs may be housed by the end of next week.

Housing lambs at this stage will allow ewes to graze outdoors longer post-breeding (provide optimum conditions for maximum embryo growth and survival), with the likely housing date at this stage forecast for the end of November/start of December.

Grazing heavy covers

The medium stocking rate (MSR – 12 ewes/ha) groups have about 30+ days grazing ahead, while the low stocking rate groups (LSR – 10 ewes/ha) are under significantly less pressure, with a strong wedge of grass accumulated and 45+ days grazing ahead.

The greatest issue in the low stocking rate group at present is grazing out heavy covers.

Grass in these heavy covers is of lower-quality and Philip said grazing of these areas is focused on getting the best balance between grazing them down tight and not restricting nutrient intake at a crucial time in breeding.

Paddocks are being split into quarters (previously halved), so that ewes are moved to fresh grass more frequently.

Ideally, the more preferable approach would be to move ewes quicker and allow them to come back to graze out paddocks in mid-pregnancy when only maintenance feeding is required, but this is being influenced by the requirement to get paddocks closed for early spring grazing.

At present, the LSR group should have sufficient grass to allow grazing to be extended until the middle to end of January.

Ram management

The compact breeding season means rams are under considerable work pressure. There are 10 rams (three ram lambs, five mature rams and two older rams on their last season) working across the six groups of 60 ewes.

One mature ram is run at all times with each group with three ram lambs and one older ram rotated between groups to take the pressure off mature rams.

Rams are being rotated every three to four days between groups to guard against infertility and also to remove any genetic bias between groups.

Rams are raddled at each move, with the raddle colour changed each week to accurately track breeding progress (start with yellow, then green, red and, lastly, blue).

As mentioned previously, Philip said that there are fewer reds than normal, with a high percentage of ewes mated in the first two weeks and all ewes mated within the 17-day cycle.

Rams will be retained with ewes for six weeks before being removed for preferential treatment.

Ram lambs and those that have lost sufficient condition may receive meal supplementation to aid recovery.

Ram lambs will be maintained on a high level of nutrition until they have recovered sufficiently to ensure their growth is not stunted or compromised.

Lamb performance

Lambs are being weighed and drafted weekly, with growth rates currently averaging 135g to 150g per day.

Drafting weights are currently 46kg to 47kg, with the kill-out percentage in grass-finished ewe and wether lambs averaging 43%.

The drafting rates in the low, medium and high stocking rate groups currently stands at about 89%, 80% and 76%, respectively, with a 6% difference between the medium and high prolificacy groups.

Lambs receive cobalt supplementation every two weeks, with worm treatment based on faecal egg count analysis.

Faecal egg counts have been carried out every two weeks since May, with treatment occurring once egg counts exceed 500. Lambs have received three doses since May, with the last administered three weeks ago.

Ewe condition and winter feeding

Ewe condition pre-mating is detailed in Table 1. As can be seen, ewes in the LSR group had the highest body condition score.

Another point to note is the high prolificacy ewes had a lower mature weight pre-breeding of 73kg versus 80kg for the medium prolificacy ewes and a higher body condition score.

Culling rates in the high prolificacy group were significantly higher at 20% compared with 11% for the medium prolificacy groups.

All stocking rates and prolificacy groups have adequate fodder conserved for the winter. All groups have over 150% of their required fodder demand for a 100-day winter. The HSR group is likely to be the only group that will require 100 days feeding indoors.

At current estimates, the MSR group has 190% of its winter feed requirement, while the LSR group has over 285% of its winter feed requirement, given it is only likely to be housed for four to six weeks.

The demo flocks

The Athenry demo flocks were established to identify the effect of varying stocking rates of 10, 12 and 14 ewes per hectare and high (weaning 1.8 lambs per ewe) and medium (weaning 1.6 lambs per ewe) prolificacy rates on the potential gross margin attainable from different production systems. The flocks are coming to the end of their third year. A summary of performance for 2014 and over the first three years will be available in early 2015.