The paddocks are now full of ewes and lambs, so the focus turns to optimising performance. As weaning approaches, the milk rearing phase of lamb production drops away and, hopefully, you have the rapid liveweight gain associated with good lactation performance. The challenge for most farms is to capitalise on this by keeping lambs on the right growth track post weaning.
The quality and quantity of forage consumed directly impacts lamb Liveweight Gain (LWG) post weaning. Over summer, pastures have lower Metabolisable Energy (ME) and protein, while fibre content increases resulting in a bulky feed. Most lambs may only achieve as little as 100 grams per day LWG on dryland pasture.
To counteract this, ME needs to be above 11 MJME with protein levels of approximately 16 percent or better. Achieving this means paying close attention to pasture management throughout summer or utilising specialist forage crops to provide the quality and quantity of feed to get lambs growing quicker.
Each farm’s individual historic lamb weaning weights and their ability to grow adequate quality and quality forage dictates the stock policies post weaning, such as store systems or finishing systems.
Attempting to fatten lambs with lower quality summer pastures can restrict ewe intakes and result in lower body condition at tupping, impacting next season’s lambing percentages. Summer forage systems can compensate for lower quality grass by providing a high-quality feed, leading to improved productivity and profitability for the farm.
Should you lack the ability to grow and harvest quality forage post weaning on dryland farms through summer, then you must consider a significant reduction of the number of lambs at weaning. Planning for this must begin now.
Worm challenge is another major factor impacting post weaning LWG. High worm challenges reduce daily feed intake and divert protein and energy from LWG for an immune response against the worm. Higher pasture worm contamination from large lamb numbers over summer results in worm challenges impacting ewe performance.
With widespread drench resistance on most farms now, we know a 14 percent reduction of lamb value occurs with the use of ineffective drenches.1 This is through poorer feed conversion efficiency and lowering of carcass weights and/or grades over time. Any drench you use must be effective. Take a simple post drench check this summer to avoid slow growing non-profitable lambs.
Using cattle to groom pasture can improve quality and reduce worm challenge. Another option is rotating undrenched ewes behind lambs to improve quality and lower egg output (refugia) which is a powerful tool in slowing drench resistance.
New data from a PGG Wrightson and PGG Wrightson Seeds trial shows grazing specialist forage crops, such as raphnobrassica or herb/clover mixes instead of pasture, reduces worm
larval challenge.
By driving high daily liveweight gain, more lambs are finished earlier. They consume less total feed, less drench is used, and drench resistance slows on your property—all while ensuring more feed is available to increase ewe performance during the critical autumn mating period. Forage proves a win-win situation for keeping lambs on the right track.
Discuss your forage crop options with your local PGG Wrightson Technical Field Representative.
