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17th February, 2019


The morning and evening hum of milking parlours harvesting milk from daily herds has ceased for a six week period. There are exceptions to this scenario but unfortunately they are akin to locating the corncrake in many areas of Southern Ireland.

Winter milk production systems are now primarily based in Northern Ireland with small pockets centred around milk production schemes in Southern Counties. Winter milk production does require a high input of supplemental ration with a cow that will respond to produce high outputs of milk.

In the current scenario of higher profitable milk production, supplemental concentrates in a winter milk scheme will return both a greater daily profit from milk sold and also an opportunity to optimise daily herd health which is linked to survivability of the herd.

Winter milk production has traditionally been associated with holstein cows producing large volumes of milk with poor health traits and an associated poor reproductive performance.  It inevitably resulted in an unacceptable proportion of the herd slipping from autumn to spring calving and vice versa.  This need not be the case by selection of genetics with enhanced health and fertility traits.  In essence we need a robust cow which will optimise the opportunity to achieve ideal BCS and locomotion scores at all stages of the production cycle.  Genetics selection has to be mirrored by excellent stockmanship, housing environment and nutritional management.

Winter milk production has fallen out of favour for many farmers because of poorer profits and lifestyle associated with year round milk production. Some farmers have either continued with winter milk or started same because of farm fragmentation, workload associated with solely spring calving, and the advent of robotic milking systems.  Robotic milking is optimised in terms of milk harvest per robot if year round calving pertains.

Breeding programmes for autumn calving begin this month. There is a stronger emphasis now than that traditionally on calving cows for a six to eight week period to optimise the opportunity with given milk bonuses over a two to three month period.  This has created a scenario whereby reproductive performance has to be optimised.

Many farmers in winter milk have used this as a crutch for poor herd management skills. Stripper cows and roll over cows have been used to achieve the winter milk bonus schemes.  Change is now on the horizon as milk companies demand milk from autumn calving cows with minimal dilution by “rollover” cows.

How can you optimise the number of cows establishing pregnancy in the next eight weeks? You need to ensure that there is an upper limit of 20% replacement rate.  Higher replacement rates reduce the profitability of winter milk schemes.

A prebreed reproductive assessment of each cow should be an integral part of your autumn calving programme. This can begin from the time cows are calved in days. The rate of repair of the reproductive tract assessed by diagnostic ultrasonography between 14 and 28 days calved is an excellent biomarker of both dry and fresh cow transition management.

It is imperative that you realise that up to 80% future herd health problems and reproductive performance are dictated by events occurring on the 8 week period precalving and the first 2 weeks post calving. There are greater risks associated with these events when there is a greater genetic potential for milk production.

Your 8 week pregnancy rate will be dictated by an ability to detect heats and the fertility of each breeding opportunity. The duration of standing heat and the number of mounts is reduced as the genetic potential for higher volumes of milk increases.

Heat Detection aids have placed a greater emphasis in recent years on motion monitoring to identify cows for AI. This has resulted in a greater risk of false positives, whereby cows are AI’d when not in heat.  It has also meant that less time is spent by stockmen watching cows not alone for signs of heat but also other health ailments.

A prebreed diagnostic ultrasonography of each cow’s reproductive tract will identify:

  1.   Which cows are cycling and the stage of their cycle?

2.      Which cows are not cycling so you can address potential health problems in the herd?

3.      Which cows have reproductive disorders preventing the expression of a fertile heat?

It is essential that you embark on this procedure now if you are to optimise your 8 week pregnancy rate for autumn calving next year.

Dr. Dan Ryan is a bovine reproductive physiologist and can be contacted at


Article written by Dr. Dan Ryan for the Farming Independent 19th of December 2017.