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14th December, 2017

BREEDING COWS FOR AUTUMN CALVING

The majority of grass based milk production systems will dry off the remainder of their spring calvers over the next fortnight. A significant proportion of these cows will not calve until March and April 2017.  Farmers like to get a break from the milking routine over the Christmas period.

In contrast, there are a group of farmers, accounting for <10pc of producers, who calve cows in the autumn and produce milk with the associated bonuses over the winter months. This group of producers is in rapid decline as the economics of winter milk production are not sustainable.

Milk processors in the South of Ireland do not incentivise farmers to produce winter milk. These processors can source milk in the North of Ireland where dairy farmers receive a winter milk bonus between 3 and 5 cents per litre for milk supplied during specific months of the winter period.  As long as this scenario pertains, there will continue to be an exodus from winter milk production in the South of Ireland.  We have placed an emphasis on low cost milk production from grazed grass.  The current strategy does not lend itself to the production of value added milk products with a short shelf line.  There are also the implications of tariffs imposed in a post Brexit era.

Winter milk production suits a cohort of dairy farmers, where farm fragmentation, workload and genetically predisposed cows geared for high volumes of milk pertain. There are very few dairy farmers who primarily focus on winter milk production.  Those producers in winter milk are also reducing the emphasis on the proportion of cows calving in the autumn.  These producers now focus on a shorter breeding programme in the December through February period.  In the past, there was a poor focus on controlled breeding programmes for autumn calving.  Cows failing to go in calf during the winter breeding programme were allowed to slip into a spring breeding programme and vice versa.

The economics of milk production now requires optimisation of autumn calving breeding programmes. The challenges associated with breeding cows are greater for autumn versus spring calving programmes.  Winter milk production has traditionally been associated with cows genetically selected for high volumes of milk production.  In recent times there has been a greater emphasis on genetic selection emphasising fertility.

The primary challenge stems from the requirement to calve cows in the autumn where there is a transition from grazed grass to indoor systems focusing on a relative high cost winter diet. The months of October and early November this year resulted in freshly calved cows grazing outdoors with a consequent negative impact on metabolic status.  Excessive BCS loss has resulted in cows with abnormal uterine repair and an increased risk of cows not cycling when greater than 40 days calved.

The primary challenge during the next 12 weeks will be the accurate identification of cows in heat when indoors. With a limited window of opportunity to reap the benefits of winter milk bonuses, it is essential to optimise the number of opportunities to get your cows in calf.

It is essential that you know which cows are not cycling prior to the start of the breeding programme. There are heat detection aids such as tail-paint, activity monitoring devices and teaser bulls with chin ball harnesses.  A sole emphasis on these aids will result in approximately 20pc of cows being ai’d at the wrong time.  Having identified those cows that are not cycling, it makes economic sense to get veterinary diagnosis of underlying causes.

Development in ultrasonography of the reproductive tract now enable cows to be accurately identified as either cycling, not cycling or cystic. The technology has been developed whereby the person scanning the cow recovers images of the ovaries which undergo pattern recognition technology.  This results in accurate identification of the reproductive status of your cows.

A prebreed scan of your cows should identify:

  1. The stage of the cycle for all cows cycling
  2. Cystic cows
  3. Will non-cycling cows respond of an estrus synchronisation programme
  4. The treatment required for cows with uterine infections
  5. Is there an underlying herd health problem in your herd?

Knowing the stage of the cycle and treating problematic cows before the breeding season begins will help maximise the heat detection rate during the first 3 weeks of the breeding season.

Finally, maiden heifers offer you the opportunity to use sexed semen with the best genetics available on the farm. Routine heat synchronisation programmes will only work successfully if the heifers are cycling. Heifers will stop cycling if housed on concrete slats, over-stocking pens and poor silage quality. A prebreed scan will identify a cost-efficient way to breed your heifers if the use of sexed semen is being considered.

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 6th December 2016.