Dairy advice: Save time and money by detecting the 'silent bullers'
Breeding programmes for spring calving dairy herds have now begun on all farms. It is essential that a primary focus is placed on accurate heat detection where AI will be used to get cows in calf.
The primary aids to heat detection are tail-paint, scratch cards and teaser bulls with chin-ball markers.
These heat detection aids will accurately identify heats in approximately 80pc of cows. However, you should spend 20 minutes monitoring activity at three hours after the morning and evening milkings. This will pay dividends. You will identify cows presenting with milk signs of heat which may not have any markings associated with heat detection aids.
You should confirm that these "silent bullers" are actually in heat by placing a gloved arm into the vagina to check for the presence of a clear "bulling mucus". This procedure will increase the number of cows accurately presented for AI. An emphasis needs to be placed on accuracy of heat detection. In an effort to maximise submission rate, cows are presented for AI based on inaccurate signs of heat or indeed misidentification of cows.
Accurate heat detection has to be your priority when one considers the financial gain of €250 for each additional heat accurately detected at this stage of the breeding season. As herd size increases, the risk of 'shy bullers' increases. Therefore, it becomes more critical to spend time observing the herd to identify these cows.
Unfortunately, most dairy herds will not address problematic cows until they are four to six weeks into the breeding season. This subgroup can account for 15pc of the eligible herd for breeding. A pre-breed scan will identify these cows and provide an opportunity to optimise the financial gain by accurate heat detection early in the breeding season.
The timing of insemination is still an issue on many farms. In our experience, too many cows are inseminated too early in the heat period. Where once a day AI service is used, the temptation is to AI cows on the day which have 'markings' at the morning milking. You need to remember that cows will not ovulate for a period ranging from 24 to 36 hours after the onset of standing heat.
Therefore, cows starting bulling at 6am are being AI'd too early at 8 to 10am. A simple approach to avoid this scenario is to identify cows in heat when monitoring activity at 9pm. The cow identified on the day up to this time enter the AI group on the following day.