Strong grass management, Stronger cow performance

Managing grass quality well is one of the most important drivers of milk solids, cow performance, and herd fertility in Irish grass-based systems. This year, many farms have seen actual grass growth run behind predicted growth, creating pressure on feed supply and forcing more supplementation. However, if conditions improve and growth moves ahead of demand, surpluses can build quickly. If those surpluses are not identified and removed early, grass quality will decline, leaving cows grazing stronger covers with lower feeding value.
The key aim should be to offer leafy (three leaf), digestible grass at the correct pre-grazing cover (1,300-1,400kg DM/ha) and to avoid letting paddocks get too strong. Once covers build, grass becomes stemmy, heading begins, and digestibility falls. Cows may then be forced to graze out heavier paddocks to regain control, but intake potential drops even when there appears to be plenty of grass available. Milk protein is particularly sensitive to this loss in energy intake, as it depends on both total dry matter intake (DMI) and quality of feed.
Maintaining quality starts with regular grass measuring – even if you are not into budgeting then knowing the cover they are going into and an idea of what is ahead of them for the next 10 days is really useful. Controlling rotation length and adjusting based on growth rate multiplied by days, and remembering the residual, will allow you to target the ideal cover. Finally, remove surplus paddocks early for bales/silage or increase your stocking rate with other animals when growth begins to run ahead of demand. Delayed action increases the risk of cows grazing poorer-quality material simply to bring paddocks back under control, reducing energy intake at a time when many herds still depend on grass to support milk solids and body condition. Weather also remains a major factor, as variable conditions can lower grass dry matter and grazing efficiency. In these situations, quick decisions on supplementation are essential to protect milk protein and avoid an energy deficit.
From a fertility point of view, this matters because cows need consistent energy intake during breeding to minimise body condition loss and support strong cycling activity. When cows are forced to clean out strong paddocks, the drop in grass quality can reduce energy supply just when fertility performance is most vulnerable. Diets based on lush grass can also be low in effective fibre, so balancing the diet remains important to support rumen health and avoid milk fat depression. Keeping good levels of digestible fibre and a live yeast such as Yea-Sacc has been proven to help this.
The most successful systems combine tight grazing control with flexible feeding, using concentrates, fibre sources, or silage strategically when grass quality or access is compromised. In practice, farmers who react early when growth starts to exceed demand are best placed to maintain grass quality, protect milk protein, and support fertility.