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Saturday 22 July 2017

Our Farm: The chaos of calving gives way to plans for the next mating season

Shane Clancy, Donnacha Keohane and Cathal McCarthy with a John Deere 6920 at the annual tractor run at Ballygurteen, West Cork. Photo: Denis Boyle
Shane Clancy, Donnacha Keohane and Cathal McCarthy with a John Deere 6920 at the annual tractor run at Ballygurteen, West Cork. Photo: Denis Boyle

Mary Kinston

As March passes, the chaos of calving should have also passed. Most herds by now should have at least greater than 75pc of the herd calved, and ideally have less than 10pc left to calve in April.

With this small window during April to somewhat 'catch your breath', focus should now turn towards breeding. While calving is challenging in terms of work load, mating is where the value of compact calving, pays off.

An average herd calving interval of 365 days is the ideal for efficiency and productivity.

Achieving a six-week calving rate of greater than 75pc means that all these cows have six weeks or more for anoestrus and to potentially exhibit their first oestrus prior to the start of mating.

Achieving all of these targets primes the system for a successful mating season.

Considering the maiden heifers, these would have ideally been vaccinated on early March for leptospirosis and BVD, and would have been at grass.

March has been rather tricky in many areas and this ideal of having heifers at grass wasn't possible in many areas as they went in and out of the sheds on repeated occasions due to the heavy downpours.

Here's hoping April is kinder and promotes weight gain. Mating the maiden heifers successfully is crucial to next year's calving spread, and will be determined firstly by the weight of the heifers at mating, the target being 60pc of mature body weight (e.g. 330kg for a 550kg cow).


While many farmers are highly conscious of the importance of heifer liveweight, those choosing to delay mating for lighter heifers will have detrimental consequences on next year's calving-spread, next year's mating, days in milk, milk solids yield and the retention of such heifers in the herd.

Ideally heifers would have been weighed prior to housing and post turnout, with any light heifer preferentially treated to avoid having to even consider this option. You must start mating maiden heifers at least the same day as the cows and even up to 10 days beforehand again to aid compact calving.

The next choice is whether to us AI or natural service. Where using bulls, make sure you have enough with ideally one per 15 where no AI is in use, and no less than one per 30 maiden heifers.

Having inadequate bull power is a common and easily solved mistake.

For those using AI many opt to use synchrony programmes to aid in its application. Generally these work well for heifers that are up to target weight. Again having sufficient bull power post a synchrony programme is important.

As for the cows, some will use pre-mating heats to identify non-cyclers prior to mating. There are differing opinions on this. Identifying and treating non-cyclers is certainly beneficial to achieving a target submission rate of 90pc within the first three weeks of mating.

However the counter-argument is that pre-mating heat detection makes the AI period very long and that the operators get sick and tired of tail painting and identifying cows before mating has even started.

Assessment

I feel that where a farmer has had a challenging calving season, with multiple problem cases such as milk fever, retained placentas, mineral issues, twins, still births, grass tetany etc. etc. then pre-mating heats may prove very useful. However, try and keep the assessment as simple as possible. For example, paint 21 days prior to mating and then top up the paint twice a week for any cows that hasn't cycled.

It also helps to use red tail plaint here, and once mating starts switch to an alternate colour, to again help you keep an eye on these non-cycling cows.

Before mating, record all the cows which still have tail paint and you have your non-cyclers. Once identified, the first question is how long has she calved, and if greater than 40 days its worth doing something with her.

If thin you could simply milk her once a day until she presents for mating. However, many would also scan or seek veterinary assistance to make sure all is in order.

If not tail painting prior to mating, then the use of once a day milking for thin young cows is often a simple and beneficial measure that can assist cows which are under pressure post calving.

For now, lets hope we get the weather to promote grazing, oestrus activity and a good start to mating.

Mary Kinston is a discussion group facilitator and consultant, and farms with her husband in Co Kerry.


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