A veterinary officer inseminates a dairy cow in Nyeri. Sub-optimal heat detection and poor timing of inseminations ignite several setbacks in your dairy agribusiness. FILE PHOTO | NATION MEDIA GROUP 

Many farmers are well-informed that good fertility of a herd is key to profitable dairy farming, as this determines efficient milk production.
However, despite this knowledge, for many farmers, timing when to serve their cows remains a big a challenge.
To begin with, the sound reproduction of a herd has a direct relationship with correct timing of inseminations manifested by oestrus heat signs.
Studies have shown that sub-optimal heat detection and poor timing of inseminations ignite several setbacks in your dairy business.
They are the major cause of prolonged calving intervals – the time from calving to the next and loss of milk production characterised by longer dry periods, meaning, you lose on profits.
There will also be loss of replacement stocks, meaning, you may be forced to buy calves or heifers to remain in business.
Further, poor insemination timing is associated with low rates of conception, which adds costs associated with repeated inseminations.
Well, in this article, we will help you understand how to tell your cow is ready for insemination.
To breakdown the science, a lactating cow can either be in-calf or not, and an in-calf cow can either be lactating or dry.
The period from calving to successful conception is expected to last 45 to 90 days.
During the period, the cow is expected to come on heat and be inseminated.
Heat detection
This is extremely an important exercise as a mistake made in reading the signs translate to a wasted 21 days.
Heat interval is normally 18 to 24 days, lasting for 24 to 36 hours in cows. With these figures, correct timing is evidently critical.
Several methods are used to detect heat, but the most commonly used by farmers are behavioural signs and or physical changes.
The signs are categorised into early heat signs, standing heat and after heat. The best time to serve is at standing heat.
Early heat
Cows need close monitoring here.
The cow is associated with increased nervousness or restlessness, she mounts other cows but walks away when mounted, has a slightly swollen vulva, she licks other cows and sniff at other cows while also being sniffed.
These signs are accompanied with reduced feed intake and bawling.
If you are able to tell the cow is in early heat, chances are high you will get the standing heat period right.
Standing heat
Waste no time here because it is the right time to serve.
The surest sign is when the cow mounts others and stands to be mounted. Accompanying this is sharp decline in milk production, frequent bawling, her tail is bent away from the vulva and the animal could forget eating because she is very active.
The cow also sniffs at others and is also sniffed. There is also clear mucus discharge from the vulva, which would be swollen and deep red.
After heat/late heat
Keep record of this, it is important as well. She will still sniff at other animals and be sniffed.
There will be dried mucus on the cow’s tail, the tail head is roughened, refuses to be mounted and there will be streaks of saliva or signs of leaking on her flanks.
Check heat signs three times a day, in the morning, mid-day and late afternoon. Not all the signs in each category may be manifested.
A heat detection efficiency of over 75 per cent would represent an outstanding performance, though this is still a standard achieved in very few herds.
Majority herds still realise only between 20 to 30 per cent efficiency, a rate resulting in far too many open days – time when a cow is not in-calf.
Once heat has been detected, cows should be served, but when?
Serving the cow
Inseminating the cow at the right time increases the chances of conception, already agreed is that this is when the cow is showing standing heat.
An AM-PM rule is applied as a guide to when you should inseminate her. In practice, if the standing heat is observed for instance in the morning, present the cow for insemination late in the evening the same day.
If the animal shows standing heat late afternoon or evening, present her for insemination early next morning.
To improve the breeding performance of a cow, serve at about 75 days after her last calving. A cow will show heat signs from 45 days after calving but it is best to delay her.
After inseminating a cow, watch her again 17 to 25 days later for any heat signs.
Few cows can show heat signs even when pregnant during this early time, following this, carry out a pregnancy diagnosis at three months to be sure, since re-insemination may result in complications.
You can also gauge whether your farm is successful in fertility management of the herd by looking at the calving interval. Effective breeding programmes, well designed should help realise a calf per cow every year.
Conception rates are also important to look at.
Good reproductively efficient cows receive the least number of services per conception.
Cows not conceiving after three inseminations can be culled if all reproductive management factors are kept in check.
There are also ways you can boost heat detection, before even you inject hormones or use heat booster powders available in agrovets.
If you can, use of vasectomised or teaser bulls has proven successful in reading signs, including animals in silent heat.
These bulls cannot impregnate your cow. Keeping breeding records, the other option, will provide you with knowledge about the cow’s oestrus, which is of great help in predicting date of expected heat.
Alongside these, maintaining a healthy herd with good nutrition of balanced rations and adequate mineral supplementation are essential for good fertility.
The writer is based at Animal Sciences Department, Egerton University. He is the founder of