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16th December, 2017

DUAL DEMANDS OF QUALITY SILAGE AND BREEDING PROGRAMMES

The vast improvement in the weather means everything to the psyche of Irish farmers. The various migratory birds are nesting and the dawn chorus is a sight to behold. Early starts and late finishes are the norm with an endless sight of chores centred around conservation of forages for the next winter period.

Grass growth rates have improved dramatically. Managing grass quality for both grazing and conservation is the primary challenge. A settled spell of good weather means everything! The quality of harvesting equipment is excellent to achieve the harvest of vast areas of silage in a restricted window of opportunity dictated by both vagaries of Irish weather and the paramount need for forage quality.

Silage quality is one of the primary ingredients in the outcome of both dry cow and early lactation transition management. The temptation in an era of poor milk prices may be one of maximising the ‘bulk’ of the first cut thereby reducing harvesting costs and the need for a second cut.

You have to be cognizant of the fact that approximately 60pc of herd health problems are associated with dry cow and early lactation transition management. Silage quality and quantity are primary ingredients. Focus on getting this right as it will alleviate a lot of the reproductive problems currently being encountered in breeding programmes.

High submission rates are an essential ingredient in optimising your six week pregnancy rate for grass based milk production systems. When evaluating your submission rate, you have to use some common sense. Late calvers which would not have an opportunity to be bred, should not be included. Forcing these cows to be bred using hormonal treatments is futile unless the cows are ‘fit’.

Aside from grass management, your primary focus has to be ‘spending time’ with your cows identifying cows ‘in heat’. As herd size increases, there is greater demand on our time and uses of aids in heat detection become a primary determinant in a decision to breed cows.

The risk of false positive heats increases with this approach. Studies have shown that these can be as high as 15pc of cows bred. Indeed, one study has shown that the pregnancy rate for cows bred to AI was lowest on a Monday. This was associated with poor observation skills at the weekend and presenting cows either just gone off heat or not in heat at all.

It is essential that you accurately identify heats and avoid false positives as you enter your second three week cycle in your breeding programme. This is a two edged sword as increases the risk of wasting valuable semen, increase the risk of introducing infection in cows not in heat and inducing embryonic death in cows pregnant to the first service.

I had cases during this past week, where embryonic death was induced by AI when the cows were not in heat. This problem is further exacerbated by the fact that up to 10pc of cows may show signs of heat when they are actually pregnant.

There is generally an air of silence when you tell a farmer that embryonic death at the crush side has been induced by misadventure with AI. Many farmers introduce stock bulls after the first three week cycle of Ai to avoid both this risk and their poor ability in heat detection.

Introducing stock bulls will help address the risk of poor heat detection, but will not address the needs of cows with reproductive disorders. These cows need veterinary attention. It is essential that you address the requirements of those cows now. Remember the ‘€ 250 financial gain’ by accurate detection of an otherwise missed breeding opportunity.

Reverting back to embryonic death, it is important that you realise that your cows may not return to heat for a period up to nine weeks when an embryo dies beyond day 25 of pregnancy. Late embryo death occurs in approximately 10pc of cows. Diseases such as Neospora, BVD, IBR, Leptospirosis and Johne’s will increase the incidence of embryo death. The incidence of twins born in Ireland is close to 5pc. However, up to 15pc of cows starts pregnancy with twins. This incidence of late embryonic death is significantly greater in cows carrying twins.

Pregnancy can be diagnosed in cows using either milk samples or scanning from day 30 of pregnancy. However, milk sample testing is restricted by the fact that you cannot age pregnancies.

Identify cows carrying twins and critically identify cows with recent embryonic deaths.

Dr. Dan Ryan is a Bovine Reproductive Physiologist and can be contacted at www. reprodoc.ie

Article written by Dr. Dan Ryan for the Farming Independent 31st May 2016.