How to best manage grass growth and quality for ewes and lambs – Poppy Frater, SRUC
As of this writing (May 5), grass growth looks pretty good across most of the country. This eases pressure during times of high input costs, but it takes good management to keep good quality grass – few stems, minimal leaf litter and plenty of clover – for lambs weaned later in the season. ‘year.
For ewes and lambs on pasture, this creates a delicate balance – how to manage grazing now for good lactation performance while keeping an eye on quality in the future – it’s no small feat.
In terms of grazing management, you can opt for fixed seeding, simple rotational grazing or leader-follower grazing.
Fixed storage during the summer months is often justifiable – the supply of weed is usually greater than the demand, so there is no great pressure to maximize usage. However, grazing still requires adaptation to grass growing conditions, otherwise grass quality later in the year is left to chance.
Under the fixed storage, the grass should be kept within the range of 6-8 cm. If it exceeds this range, the stock will become more selective and areas of poor quality will form. This is where reducing the grazing area or bringing in more livestock is beneficial.
A simple rotational grazing scheme could stock the area relatively heavily (up to 28 ewes and lambs/ha) with access to a buffer zone when grass heights do not reach target at entry (8cm) or could store more conservatively (20 ewes and lambs/ha) with the option to remove pens for silage when grass height exceeds pre-entry target of 8cm.
A rotation of three weeks, three days (three weeks rest, three days grazing interval, so eight paddocks) is often a good framework for beginners – the rest period should be 12 to 21 days, to be adapted according to depending on the pre-entry grass height and graze about 5 cm. Any shorter growth rate and lamb will be compromised and/or ewes will lose more condition.
The follower pasture is where a priority group (often ewes with twins, ewes with triplets, or finisher animals) reaches the paddock first and grazes the best stuff about 6cm away, followed by a lower priority group (often ewes and singles, cows and growing calves or heifers) that may graze up to 4-5 cm.
The lower priority group is the one that can use the lower quality grass without compromising animal performance to a high degree. Leader-follower grazing is great because it can be difficult to get low enough with a single group without affecting their performance. The followers should not be more than two paddocks behind the leaders. It’s worth looking closely at follower performance – does practice affect profitability?
Topping works as a last resort to correct pasture quality if it has gotten out of control – you want a clean cut, so often a mower is better for the job than a pruner – and it should be cut low (4-5 cm) to promote the growth of green leaves.
This is often a good compromise once or twice during the grazing season, as it is simple and avoids having to graze the stock too low. Deferred grazing later in the season could also be another option – why bother reducing fuel if it can be kept as a standing hay crop for ewes or cows weaned later in the year?
There are many options to consider, so keep priorities in mind. Short-term animal performance is the first point of call with an eye on further performance – managing grass quality.
It’s not simple and will always require adaptation and refinement, but it’s worth it to ensure these lambs grow well and profitably.
The recently released Forage First Sheep Systems have more ideas for profitable herd management and are available online or in hard copy on request from [email protected] Also keep an eye out for the launch of the FAS Grazing Mini-Webinar Series on May 26th.