The first two months of life for the calf is the greatest time to convert feed into growth. Hence it is crucial that calves get off to a good start to achieve target breeding age and weight prior to breeding. I see growth rates vary considerably among farms, ranging from 0.2 to 1.3 kg/day during the first six months. This range will have a big impact on the time of first breeding.
Growth rate must be maximised during the milk feeding period of which careful attention must be focused on giving colostrum to the new born calf and it should be given within two hours following calving. Absorption of antibodies is greatest in the first two hours of life for the calf. I encourage a simple one, two, three approach should be adopted here:
- Use colostrum from the first milking for the first feed
- Give colostrum within two hours from the calf’s birth
- Give at least three litres of colostrum
Across most Irish dairy farms, calf birth rate ranges from 40 – 45 kg, therefore the calf will require approximately 325 g of milk solids (2.6 litres of fresh milk assuming 12.5% solids content). However, if offering liquid milk in the form of a milk replacer, offer at 10% of bodyweight to supply 400 – 500 g of milk solids per day. I always pay attention to the constituents of the milk replacer farmers are using, making sure the protein is between 20% – 25% and fat 15% – 20% respectively. I also advise to make sure all calves have some digestible high energy protein coarse ration in front of them, adequate fibre (hay, chopped straw) and clean water.
The following table is a useful guide to target growth rates:
|Age (months)||Target growth rate, kg/day|
|0 – 4||up to 0.9|
|4 – 12||0.7|
|12 – 16||0.8 – 0.9|
|16 – 24||0.7 – 0.75|
At first breeding, dairy heifers should be 55% – 60% of mature weight. In order to achieve this approximate weight of 300 – 360 kg at 13 – 14 months, a good average daily gain of 0.75 kg is required every single day from the rearing period until first breeding. The overall aim is to achieve 80% – 90% of mature weight at calving of which equates to approximately 550 kg at 24 months old. I speak a lot about Body Condition Score but it is vital that it is in a range of between 3.0 – 3.25. The age at first calving is a strong driver of farming profitability due to the high cost of raising replacements of which is estimated to be €1500 per heifer.
Spring born heifers should be offered good quality silage and depending on its overall quality, it should be supplemented with 1.5 – 2 kg of an 18% dairy replacement winter feed heifer cube. I strongly advise checking target weights via weighing with regular checks on body condition together with worming, vaccination etc.
The pre-calving heifers should also be offered good quality silage and some straw to keep rumen fill at optimum level. I encourage farmers to feed 2.0 kg of a replacement heifer cube 6 – 8 weeks prior to calving together with approximately 100 grams of a pre calving mineral. Paying particular attention to magnesium, vitamin E, selenium and iodine.
In summary to having a successful replacement heifer programme, the onset of birth for the new calf must hit the ground running in terms of achieving high intakes together with high growth rates. At key stages of a dairy heifer rearing programme, these target weights must be accomplished particularly at weaning, at start of first winter, at mating and at calving. Constant vigilance should be exercised at all times of these replacement heifers in the herd, paying particular attention to a solid nutrition, health, vaccination, winter housing, silage quality and a concentrate specification feeding programme.
If you have any questions or need advice on a weight programme for in calf heifers, why not pop one of our agri experts a question here.
- Body Condition Scoring
- feeding programme
- winter feed