Missed breeding opportunities carry a significant cost

THIS IS a critical stage of the breeding season and the challenges come under the following headings: ÷Heat detection ÷Stock Bulls ÷Nutrition ÷Herd Health

HEAT DETECTION

Farmers are placing greater focus on the use of aids for heat detection as the primary way to identify cows for AI. 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 AI 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 completed at least three weeks of AI. They are being encouraged to synchronise heats in those cows not detected.

In my experience the one size fits all approach does not address the needs 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 behind 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 30pc 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 12pc 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 risks 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 AI 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.

NUTRITION

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 achiev- ing sustained peaks in milk production.

Supplementing concentrates with the required minerals and vitamins remains essential to avoid negative energy balance in the herd and to ensure you optimise the reproductive performance.

HERD 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 Johne’s Disease in your herd.

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