September is often an extremely busy time on the average dairy farm.
Spring calving cows are still coming in, peak calf rearing numbers on milk feed is the norm and thoughts are turning to silage and hay.
Last month I discussed how important managing transition — the three weeks before and after calving — is for herd success.
As cows move closer to peak lactation, it is important to focus on a couple of things, but one of the most important things to focus on in early lactation is: are your cows maintaining their body condition?
The loss of body condition in early lactation might be inevitable when cows, who have been bred genetically for high production, put their all into achieving high levels of milk production, but if their body condition loss is excessive or uncontrolled, the consequences for production and especially reproduction can be very significant.
I generally advise that cows should ideally not lose more than 0.6 of a Body Condition Score (BCS) on an 8-point scale between calving and mating, which correlates roughly to no more than about a 30kg loss of body weight.
Losses greater than this have been associated with anoestrus and poor reproductive performance, with excessive body condition mobilisation linked to direct and indirect effects on the ovaries and developing eggs.
Some of our robot-milked herds can track body weight loss and some herds will measure and record body condition at several stages of lactation to monitor body condition changes — but they certainly are in the minority of herds.
Most herds have no record of changes to their cows’ body condition other than maybe the ‘vibe’ or the herd owner’s impression that they might be losing condition too fast.
Modern cows have such a great ‘will’ to produce milk that they will do it at the expense of body condition and subsequently reproduction if we are not able to prevent loss of condition, especially in early lactation.
Cows who are excessively fat at calving are more prone to metabolic diseases like ketosis and fatty liver, which can also have severe impacts on production and reproduction, while cows that calve in poor body condition will have significantly poorer reproduction performance than those calving in the ideal condition.
If farms are not measuring and monitoring body condition at calving/transition and loss of BCS in early lactation, it is often difficult to determine whether this is the cause of poor fertility due to lower than expected cycling (submission) rates and lower than expected conception rates when we get into the joining period or start to pregnancy test the herd.
Many a dollar and hour has been wasted investigating a non-existing disease when prolonged negative energy balance causing loss of body condition in the early lactation period is the real cause of reproduction failure.
There are some exciting developments in the space of measuring and recording body condition in dairy cows using technology assisted by artificial intelligence and both 2D and 3D cameras being reported in the literature recently, so I am expecting this to become increasingly available to producers in the coming years and will make the process of monitoring body condition simple.
Until then, having an experienced herd health veterinarian visually score the herd several times over the year may represent excellent value — especially if you have experienced issues with production, fertility or metabolic disease in previous seasons.
Proactive herd health managers will recognise that measuring and monitoring critical indicators of herd performance like production, cell count, body condition, etc, allow them to make more timely interventions to prevent disasters rather than simply responding to them, which is always a better option.
If you think that your herd might be losing too much condition in early lactation, talk to your vet to organise some BCS monitoring to be performed and your nutritional adviser to look at some strategies to manage this silent thief of your reproductive success.
Dr Rob Bonanno is ProDairy Gippsland’s lead consultant.