Lamb performance issues impacting killouts of lambs at slaughter can be put down to many reasons, including bad weather conditions and the expense of feeding concentrates to lambs.
The lower performance in lambs this year has shown an increased number of lighter, under-fleshed lambs with carcass weights of 16-17kg and fat class 1 lambs being slaughtered.
These lambs are posing challenges for processors to market, and are not achieving their potential for the farmers that supplied them, with the lambs potentially being more suitable for the live trade, or to be fed more concentrates to achieve a heavier carcasses.
Lamb performance
Fiona McGovern, at Teagasc Athenry, Co. Galway, provided an update on the flocks there, where close attention is being paid to the condition of lambs being sent for slaughter.
McGovern said: “Grass growing conditions are at an optimum for the time of year here in Athenry. Grass growth is currently above average at 75kg dry matter (DM)/ha, with a demand of 35kg DM/ha.”
“All lambs in the INZAC (Ireland New Zealand across breed animal comparison study) flock were weaned on June 13, at approximately 100 days of age.”
McGovern said the “lambs are currently averaging at 38kg liveweight with a growth rate of 230g/day in the month post-weaning”.
The first group of lambs has been drafted and sent for slaughter from the Teagasc flock, with all other lambs receiving a cobalt drench fortnightly at weighing.
“This year we are carrying out some additional work that focuses on lamb performance post-weaning,” McGovern added.
Assessing lambs
The additional work being undertaken at the Teagasc flock is to assess the feeding of weaned lambs and the resulting effect on the carcass of the lamb.
McGovern said: “A selection of 24 lambs have been individually housed and are being assessed for grass dry matter intake and digestibility.
“At the beginning of September, we will measure 250 INZAC lambs through a mobile CT scanner to assess carcass conformation and rumen size prior to slaughter.
“The methane output of these lambs will also be monitored, which will enable us to investigate relationships between rumen size and methane output in addition to assessing the impact of genetic merit on carcass traits.”