One option is to reduce the milking frequency in your first calvers.

Despite the winter (so far) being kind withamazing rebound growth rates post the drought, on many farms the supplement levels going into calving are below normal as the stores have been eaten. So, we need a good start to spring to keep things on balance.

We also didn’t need heifers coming home from grazing 100kg behind target, but on a number of farms this is what we’ve had (refer to figure 1).

Figure 1: a mob of heifers home from grazing this May.

Figure 2: data from the same heifer mob from their May weigh. All the heifers are behind, so the whole mob needs aggressive action.

We know that underweight heifers produce less milk, will take longer to cycle, have a poor 6-week in-calf rates, and are more likely to be empty in their first lactation. Below is some data from a local herd last season, but I could draw this graph 100x over.

Figure 3: looks at the impact of weight at 22 month old on first-lactation 6-week in-calf rates in a mob of heifers. The heifers that were above target weight (based on MINDA Live targets) in May had a 79% 6-week in-calf rate, those that were >9% behind had a 60% 6-week in-calf rate.

So what can you do?

• Weigh your heifers now if you don’t have a May weight on them – ask how big is the problem, how many are affected – and therefore you can take action.
• Make a plan (start by reading this article!).
• Feed your heifers as much as your feed budget allows. You’ll be surprised what heifers can eat – for example 12kgDM. Heifers will continue to grow in the last couple of months of pregnancy, and although you may have to tolerate slightly higher residuals to fully feed them, it will pay off post-calving. Heifers don’t put the extra feed into making the calf bigger either.
• Keep the heifers separate or mix in with some lighter cows. Either way, with whatever you choose, start this mob well before calving (>4 weeks) and leave the mob alone i.e., heifers take a long time to acclimatise socially to the herd.
• Ensure your heifers are well adjusted to the post-calving feeding before calving starts i.e., feed pad, maize, PKE, or in-shed meal. Heifers don’t know they’re supposed to eat meal while the milking is occurring, so this needs to be learned ideally before calving. Make sure the post-calving feed is highly palatable too as this helps with intake.
• Consider other tools such as monensin to minimise body condition score (BCS) loss post-calving.
• Consider a reduced milking frequency for heifers in the colostrum up to 3-6 weeks post-calving. The impact of once-a-day (OAD) milking for 6 weeks post-calving, is only 5-10% of the total season’s production for that sub group, therefore across the whole herd (with heifers being 20% of the herd) this only makes up to 1-2%!
• Re-check this at-risk group 4-6 weeks before your planned start of mating (PSM) i.e., get your vet to individually BCS them, and decide whether they need to have preferential treatment coming into the mating period, as this timing for reduced milking frequency may suit your management better. It’s not too late to take action at this time point too.

Once-a-day milking (OAD), 3-in-2 (milking three times in two days), or 10-in-7 (e.g., milking OAD on Saturday, Sunday, Tuesday, and Thursday) can all be effectively implemented for at-risk groups, whole mobs, or whole herds for either a short (less than three weeks) or long period. While there will be negative impacts on production, there will also be positive effects on pasture management, staff workload, cow health, and cow metabolic state.

The data on the other milking frequencies for variable periods of time in early lactation aren’t as well researched – with most of the information being reported from farmers who are using these strategies on farm. However, the somatic cell count (SCC) is usually lower in 3-in-2 and 10-in-7 when compared with OAD milking. There will be slight variations in production but the convenience for staff and pasture management means that many herds like these approaches better.  Every farm will have slightly different management factors to consider.

I’m often asked about in-shed feeding and the risk of animals missing out on meal and minerals if they only come to the shed OAD. So instead should these animals be kept in the twice-a-day (TAD) milking mob but not milked when they get to the shed? While we don’t have a study to answer the question, from first principles – the walk to the shed in the afternoon on some farms may outweigh the benefit of OAD milking. For example, on a hilly farm with a 1.5km walk to the shed, a cow uses 15ME to get to and from the afternoon milking; this only balances out if they eat an extra 1.5kg meal in the afternoon milking! If they drop 20% production on OAD that’s about 30ME still saved each day – so there’s still a net gain from the OAD. That said, animals that are kept in the TAD herd while being milked OAD do take longer to adjust to OAD milking i.e., the afternoon stimulus is there to produce milk, so potentially there is an increased mastitis risk with this option (milk drip during milking etc). 

To summarise:

If your heifers aren’t where you want them to be, but they have many lactations ahead of them, then they are your very best genetics. It’s a matter of how important they are to you? There are always options for recovery and the best time to make a decision and take action is now.