Critical time to examine your replacements
More and more farmers are weighing replacements. If you are not a great judge of weights, perhaps you might call in the Farm Relief Service or some one that can help you with weighing.
Time is quickly passing for bringing backward animals back on track for early breeding in spring, and for bringing backward in-calf heifers up to target.
You should aim to have all your heifers fit for breeding in April. The consequences of not having them up to target weight are very serious.
It will result in breeding heifers too light, which can reduce yields by more than 150 gallons of milk for the first two lactations, or calving too late, which results in a cycle of late calving, or calving at almost three years old, which is very costly.
It was never more important to have early calving heifers. We are facing into a period where there is likely to be a substantial premium for February milk in order to reduce peak supplies and reduce the cost of expansion in milk processing. Therefore, every farmer should start building up a compact mid-January/February calving herd, and this can only be done by starting with the heifers.
Despite some complaints about proposed early spring milk price premiums, and penalties for high peak supplies, it seems a logical way of preparing for the 50% expansion in milk production up to 2020.
In the vast majority of cases, a compact mid-January/February calving herd will also produce milk more efficiently from grass. However, adequate time should be given to bring forward calving dates, because about one third of our cows calve after March, even if calving patterns are improving in recent years due to more fertile heifers and better management.
Data from the ICBF regarding the calving age of replacements are a real eye opener regarding the inefficiency of replacement rearing on Irish farms. Statistics from ICBF calving reports indicate that only 54% of dairy heifers calve at the target age of 22-26 months. The statistics are based on 10,000 dairy herds sending Animal Events data to the ICBF. The data also indicate that the top 5% of farmers calve all their replacements within the target age, while the bottom 5% calve none of their replacement within the target age.
Replacement Targets
Holstein/Friesian (HF) heifers should be at least 330kg in April for breeding. That gives less than 100 days from now to adjust feeding.
Moorepark data suggests that, even with good silage, weight gains will be about 0.35kg per day, or 35kg in 100 days. Getting them to grass early will help, but cannot be relied on. Good silage plus 2kg of 18% protein concentrate with suitable minerals should give weight gains of about 0.60kg per day, or 60kg in 100 days.
Based on those figures, heifers would need to be close to 300kg now to reach target for April breeding, fed on good quality silage alone. Heifers weighing around 250kg getting silage plus 2kg of concentrates will fall slightly short of target, but an extra few weeks on good grass or a slight delay in breeding should have them OK.
Lighter heifers should get good silage and 2kg of concentrates, and aim to get them to grass as early as possible and perhaps breed them in May.
Heifers should be grouped and fed according to weight. Make sure they are free from parasites.
If at all possible, avoid late calving heifers. Several Teagasc trials show weight is more important than age at calving. April-born heifers can be calved down successfully in February at 22 months. Minimum target for NZ/FR heifers in April is 315kg, and 300kg for Jersey x HF. HF in-calf heifers should calve down at 550kg (minimum), NZ/FR at 525kg, and Jersey x HF at 490kg. Their weights and condition scores should be carefully assessed now, and remedial action taken where required.
