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23rd February, 2019


This is a critical stage of the breeding season, the seeds have been sown to establish next year’s calf crop. The challenge now is to ensure these seeds germinate, establish a firm rooting system and create a branched network of life within the womb of the cow.  This latter analogy is easily visualised when you sow grass or barley seeds.  The implications of poor preparation and management of a grass seed crop are easily visualised.  The same implications pertain in terms of compact calving if the preparation and management of the dairy herd prior to and during the breeding season is not optimised.

The seeds have been sown to establish over 50% of next year’s calf crop at this stage of the breeding season. Close to 50% of the seeds sown will fail to be either fertilised or hatched by day 8 after breeding or create a pregnancy signal by day 13 after breeding to prevent the cow returning to heat by day 18 to 24 after.

Dairy farmers have to focus over the next month on the grass seeds that have been sown and to ensure that those seeds that fail to germinate are detected and given an opportunity to re-establish a pregnancy.

In practice the challenges come under the following headings:

  • Heat detection
  • Stock Bulls
  • Nutrition
  • Herd Health

Heat detection

Psychologically farmers are good to identify cows in heat during the first three weeks of the breeding programme. The demand of time and interest to watch cows for signs of heat wanes after three weeks.  Farmers have, therefore, placed greater focus on the use of aids to heat detection as the primary way to identify cows for A1.  These aids include tail paint, scratch cards, teaser bulls, and activity monitoring devices attached to either the ear, neck, leg or inserted in the stomach.  Unfortunately these aids can result in cows either not being detected in heat or presented for A1 when not in heat or indeed pregnant.  This is a significant cause of concern as missed breeding opportunities cost in excess of €250.  Farmers have competed at least 3 weeks of A1.  They are being encouraged to synchronise heats in those cows not detected.  In my experience the “blind” approach to a “one coat will fit all” does not address the need of the herd.  If there are underlying stressors, those synchronisation programmes to induce heats will not work either in terms of heats detected or the fertility ensuing the breeding programme.  The oestrus synchronisation programmes are most successful if the cows are already cycling and heats have been missed.

Do not consider “blind” oestrus synchronisation until you evaluate using ultrasonography if the cows are “fit” for same. In my experience, nearly 30% of the cows presented as not detected in heat are not suitable for oestrus synchronisation as they are either reproductive culls, have reproductive anomalies not addressed by inducing a heat, or were pregnant in the first instance.  It might surprise you that 12 pc of cows presented for ultrasonography in the past month as non-detected heats were pregnant!

Tease bulls with chin ball markers are an excellent aid to heat detection. However, you need sufficient tease-bull power to ensure they get rest periods and in addition, an injured teaser bull will have a reduced work rate and not identify cows in heat.

Stock bulls

The introduction of stock bulls brings the risers of infertility, sub fertility and injuries. Semen testing will help identify infertile bulls but will not identify those bulls failing to complete the art of mating the cow.  In my opinion, cows should be bred to A1 for the first three weeks after introducing the stock bull to deal with repeats.  This will also help you keep a closer eye on the progress of your breeding programme.


Are we expecting too much from grazed grass? Producing milk solids cost efficiently from grazed grass is only one part of the equation of sustainable food production.  Cows have to stay longer in our herds with reduced incidence of lameness, mastitis and an ability to establish pregnancy within a 13 week breeding programme.  Your cows are now in peak milk production.  This year is an exceptional case in terms of cows achieving sustained peaks in milk production.  Supplemental concentrates with the required minerals and vitamins are essential to avoid negative energy balance, and the optimisation of reproductive performance.

Animal health

The current significant health ailment in many herds is the high incidence of stomach and liver fluke. If your cows are scouring, get faeces samples tested for fluke and worms. These conditions will depress the immune system and increase the risk of IBR and Johnnes’ disease establishing clinical cases in your herd.

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

Article written by Dr. Dan Ryan for the Farming Independent  6th of June 2017.