Time to start thinking about weaning

As we move into June we need to plan for weaning of mid-season flocks. The recommended age to wean lambs at in most grass based systems occurs at 14 weeks or 100 days so as they can transition over to a forage based diet. Ciaran Lynch, Teagasc Sheep Specialist discusses weaning options

Weaning earlier

In a number of circumstances which will be outlined, weaning earlier than this can be a positive management decision. For twin rearing ewes milk yield peaks at approximately 5 weeks post lambing and declines thereafter, this coincides with an increased grass intake in lambs and correspondingly a gradual reduction in the ewe’s requirement as displayed in Figure 1. From 7 to 8 weeks onward lambs begin consuming increasing amounts of grass and this accounts for an increasing proportion of their diet with less reliance on milk from the ewe. By the time lambs reach 10 to 12 weeks of age intake has increased and lambs are consuming up to 1 kg Dm of grass per head per day and are now competing with ewes for feed. At this point in ewe lactation, the relationship is not necessarily mutually beneficial particularly where grass supply is limiting and quality has declined.  

Figure 1. Grass intake for twin rearing ewes, lamb and combined ewe and litter for the early part of the grazing season. 

Delaying weaning beyond 14 weeks can have a negative impact on both ewes and lambs and indeed grass land management. The example presented in Figure 2 illustrates the timeline and key management dates for a flock that started lambing in early March. A point often overlooked is the interval from weaning to mating each year. If we use this example and assume a two week drying off period post weaning it only leaves 14 weeks from then until ram turnout. This may seem like a long time but when we consider it can take up to 10 weeks to regain 1 unit of body condition, this window becomes shorter.

Weaning on time

Weaning on time allows ewes to be dried off in a timely manner potentially avoiding some issues with mastitis. Culls can be identified early and either drafted or fed on for sale.

Figure 2. Production cycle for an early March lambing flock

From a lamb perspective weaning on time means they can be given access to the best available grass and not forced to graze out fields, thus overcoming some issue around grass quality at this stage of the season. Lambs can be batched according to gender and weight and providing targeted supplementation becomes easier where needed. In addition it also reduces group size leaving handling and routine management tasks easier.

From a grassland perspective weaning will firstly reduce feed demand as ewe intake can be restricted during the dry period (see Figure 1) reducing the pressure on the system.  It also enables leader follower system to implemented practising grazing (aftergrass etc.) for lambs and allowing for a tighter graze outs following them with dry ewes.

There are a number of circumstances where weaning earlier than 14 weeks is a good management decision that can have a positive impact on the system by benefiting the lambs, ewes or reducing pressure on feed supply.  Earlier weaning from 10 weeks onward can be successfully implemented on farms; particular attention needs to be paid to meet the lamb’s nutritional needs and address any health issues promptly.  

There are a number of situations where earlier weaning may be a benefit 

• Yearling ewes – weaning at 10 to 12 weeks allows for a longer dry period for the ewes an important consideration as these animals are still growing and developing. Additionally the ewe milk supply and contribution to the lamb’s diet will be lower anyway than that of a mature ewe therefore transition to forage or forage + concentrate early won’t have the same impact.
• Reduce feed demand earlier. For farms that struggle to maintain feed supply during the early to mid-summer period e.g. drought prone farms or those highly stocked it can reduce the demand earlier and prioritise grass for the lamb crop
• Where flocks consistently struggle with condition. This can be a vicious cycle that can be hard to break. Earlier weaning gives a longer dry period and more time to deal with issues with in the flock.

Teagasc Sheep Open Day

For more information visit www.teagasc.ie/sheepopenday where you can learn about the technical information available on the day.

The Teagasc Sheep Specialists and Researchers issue an article on a topic of interest to sheep farmers on Tuesdays here on Teagasc Daily. Find more on Teagasc Sheep here. For any further information or assistance contact your local Teagasc Office here: Advisory Regions.