Farmers must prioritise the next generation of milking cows by ensuring that the target weights of their replacement heifers are realised over the coming months.

With this in mind, heifers should reach 30% of their mature bodyweight at six months of age and achieve 60% of mature weight when bred at 15 months.

Over the next few months, optimal average daily gain may be difficult to maintain when grass growth/quality declines and grazing conditions become more challenging. So it is important to consider where your replacement heifers are in relation to targets (% of mature weight) currently.

By weighing heifers in early autumn as opposed to weighing at the point of housing, farmers can identify which animals are behind target. The best advice is to group accordingly and make alternative plans for heifers below their target weights.

Underweight heifers are considered to be those that are 5% or more below target bodyweight. Therefore, the regular weighing of heifers can help farmers to keep track of performance through the season.

Heifers that are lighter than this should be separated and given priority access to the highest quality grass and be re-introduced to concentrates depending on their weight relative to the herd’s target.

Higher weight gains can be achieved from grass rather than from winter/silage diets and a good response to autumn supplementation can be achieved. Should grass be in short supply and quality or when conditions are deteriorating, under-target replacement heifers should be fed a supplement until housing time to maintain weight. To increase growth rates, 1-2kg of concentrate/head/day should be sufficient.

Research shows that youngstock at grass in summer can achieve a weight gain of 0.85kg/day on grass alone. Come the autumn, where 1kg of concentrate plus high-quality grass are offered, average daily gains of 1kg/head/day can be achieved.

For more information, contact your local Agritech Sales Advisor here.

How to hit replacement heifer targets

For most parts of the country, grassland management has proven a struggle to date this year, given the contrasting rain levels between early and mid/late summer, contributing to sporadic periods of sustained high growth rates.

However, as we approach the later quarter of the grazing season, it is important to maximise perfomance off grass, while also setting the platform up correctly for Spring 2024. As always, we’re hoping to control the decline in milk production from here to the end of lactation. Milk yield in normal conditions will drop off 2.5% per week or 10% per month once we get to mid lactation.

Energy Deficit  

Any drop greater than this indicates an energy deficit, which would signal deteriorating grass quality or where a deficit occurs, the herd’s dry matter intake capacity may not be being met. However, milk protein and butterfat should be incrementally increasing at this point, with the target being at least +0.05% per month. Milk protein is energy based and where grass quality has suffered, summer milk protein percentages have been similarly impacted.

Next Generation

It is also a good time to reassess where we stand with the next generation of milking cows – that heifers are still on track to achieve their target weight for age (% of mature weight). Weighing now compared to weighing at the point of housing provides the opportunity to identify heifers that are behind target, and to make alternative plans where these targets are not being met.

The threshold figure for 2022 spring born weanling heifers is approximately 198kg in mid-September (33% of an assumed mature weight of 600kg). Heifers that are lighter than this should be separated into their own group and given priority access to high quality grass and supplementary concentrates (depending on how below target they may be).

Higher weight gains can be achieved from grass rather than from winter/silages diets and a good response to autumn supplementation can be achieved. Research shows that youngstock at grass in summer can achieve weight gain of 0.85kg/day on grass only. While in the autumn where 1kg of concentrate plus high-quality grass is offered, Average Daily Gains of 1kg/head/day can be achieved.

For more information, contact your local Agritech Sales Advisor.