Ketosis is often one of the unseen factors driving down fertility on many farms.
If you have issues with fertility, you need to check if cows are suffering with ketosis, as it could be contributing to the problem. Ketosis is caused when cows go into extreme negative energy balance around calving and are forced to mobilise excess body tissue. This leads to higher than acceptable ketone levels in the blood (BHBs).
Energy balance is key to return to cyclicity, so on average cows with ketosis take 22 days longer to return to service. Energy balance also has a significant impact on the viability of the egg: follicles that produce the eggs we serve at first service start to be produced in the transition period, so energy balance in transition and early lactation is important. Ketones and fatty acids produced from the breakdown of body fat reserves are toxic to the eggs.
Cows at risk of ketosis also face more health challenges, as can be seen in this graph:
How Can We Monitor Ketone Levels?
1. Milk Quality Analysis: Fat/Protein Ratios
Monitoring the fat/protein ratios for cows on their first milk recording (<41 days in milk) can give an indication of the level of ketosis risk. The target is to have less than 25% of cows with a high fat/protein ratio at any time (green line). More than 40% of cows affected gives an indication that there are likely to be problems associated with ketosis that month; this is likely to show up in the fertility in around six weeks’ time.
2. Milk (Dipsticks) Or Blood BHBs (Ketone Meters) On Fresh Cows 2–21 Days After Calving
To be truly accurate, cows should be tested twice in the first three weeks. To get a representative sample, you need to check 12 cows every 2-3 weeks (or all fresh cows if you don’t have this many calving) so this could be done as standard at a routine visit. Occasional testing may underestimate the problem, so it is better to carry out regular sampling.