The recent challenges facing sheep producers in terms of poor slaughter performance in lambs are also being witnessed on Tullamore Farm.
A large batch of 82 lambs were drafted for slaughter at the end of last week and will reduce the pressure on the farm to try and salvage an autumn grazing season following a sustained period of negligible rainfall and poor grass growth.
Farm manager Shaun Diver had been anticipating poorer slaughter performance based on lambs previously drafted and also learning from the negative effect drought had on lamb performance in previous years.
As such, Shaun had increased drafting weights and was placing more emphasis on fat cover and predicted killout of individual lambs. But like most farmers in similar situations are experiencing this year, slaughter performance was still below par.
The 82 lambs recorded an average killout percentage of 42.2% as detailed in Table 1. This is 5.2% lower than the corresponding period in 2021 and also hides a big variation within the group.
When analysed on gender, ram lambs (53 head) recorded a marginally higher average killout percentage of 42.5% with ewe lambs (29 head) killing out at 41.7%. This is likely influenced by the fact that ram lambs were being supplemented with 0.25kg concentrates for three weeks pre-slaughter.
Ram lambs were drafted at a higher carcase weight of 47.87kg with the heaviest dozen lambs in the group ranging from 50kg to 53kg. Shaun had not initially planned to take these lambs to this liveweight but many were short of flesh at the previous drafting. They were then treated for worms and had to be retained until their withdrawal period passed last week.
The lowest killout in the batch was 38.2%, while the highest killout was recorded at 48.4% in a U grade lamb sired by a Charollais ram to a Texel-cross ewe
In hindsight, this worked out OK with many of these lambs, some of which were horned lambs that brought the characteristics of background Scottish Blackface breeding to the fore, recording a killout of just 39% to 40%.
The lowest killout in the batch was 38.2%, while the highest killout was recorded at 48.4% in a U grade lamb sired by a Charollais ram to a Texel-cross ewe.
Many farmers have reported in recent weeks that the usual parameters influencing killout including conformation, fat cover, gender, diet and liveweight have not been as apparent this year and, as such, it is more difficult to draft. An analysis of the individual slaughter performance of lambs in Tullamore would back up this statement.
While U grading lambs achieved an average killout of 44.1% and ranged in the main from 43% to 46% killout, there were also a few lambs that killed from 39% to 42%. Likewise, fat class 2 lambs recorded a lower average killout in the region of 40% to 41% but there was only one fat class 2 lamb among the 14 lambs which failed to reach the 40% killout mark.
Poor slaughter performance has been a feature of lamb performance in 2022. The performance to date in 2022 is detailed in Table 2.
The killout achieved early in the season is 2% lower with this rising to 4% to 5% since the full effects of drought kicked in.
Shaun says: “It was one of the most challenging years to manage grass. The first dry spell in June quickly lowered the dry matter in grass and grass headed out much quicker.
“Lambs were less content and you could see lambs growing but not holding the same cover of flesh.
“We had a small reprieve but the high temperatures and lack of moisture in recent weeks has hit us hard. We tried to prioritise some aftergrass for lambs but, again, quality has been fierce hard to control and lambs have no right dying power despite handling OK.”
There are approximately 134 lambs left to finish on the farm. These include 56 ram lambs and 78 ewe lambs. Meal supplementation has been introduced to ewe lambs this week at a rate of 0.3kg per head, while supplementation to ram lambs has increased to 0.47kg per head.
Performance will be monitored closely along with grass growth and a decision may need to be taken to increase supplementation levels if grass growth does not quickly respond to rainfall. “We are in a very tricky position. Our farm cover is about 360kg DM/ha when at this stage of the year you would be aiming to be building that towards 1,000kg DM/ha. With breeding around the corner, the priority has to switch from lambs to ewes and this could mean upping concentrate levels to build covers for ewes. Concentrates are dear but we may have no other choice but to feed extra to keep lambs moving.”