Farmers find it difficult to keep fresh feed in front of these late calvers on a daily basis. There is a greater risk of moulded and heated silage being fed to these cows without the required mineral supplementation.
Over-conditioned cows associated with long calving intervals will also fall into this group. The easy solution tends to be one of selling these late calvers. Good routine management will ensure a very profitable late calver portfolio.
In tandem with our late calvers which are generally housed indoors, our breeding groups are now grazing outdoors day and night.
The primary focus in our breeding programme has to be ensuring our cows are fit for breeding. Too much emphasis has been placed on minimal or zero input of concentrates when cows are full-time on grass.
This may be the case under ideal grazing conditions for herds with 305-day yields averaging 6,000 litres and 20pc first lactation cows.
In reality, increasing numbers of cows on a restricted land base and the vagaries of pasture quality and quantity require concentrate supplementation prior to and during a breeding programme.
You need to be cognisant of the fact that egg quality depends on its experience for the previous eight-week period and the first two weeks after fertilisation will dictate the ability of the cow to recognise that there is an embryo present.
The latter chain of events will primarily dictate the number of cows repeating to either AI or the stock bull.
A diet balanced for energy, protein, fibre and minerals is essential to ensure your cows are gaining body condition going into a breeding programme. Environmental stressors have to be minimised to ensure you achieve in excess of a 90pc submission rate in the first three weeks of the breeding programme.
Unfortunately, stressors such as lameness, poor body condition score (BCS), mastitis, milk fever and calving difficulty will leave up to 30pc of cows unfit for breeding.
Hormonal treatments may induce heats in these cows but outcomes are poor relative to a fit cow showing a natural heat. The primary focus has to be preventative health management during the dry and early lactation transition and also during the breeding programme.
Many farmers will focus on the use of AI for four to eight weeks before introducing a beef sire as mop-up bull.
Various technologies have been introduced over the past 10 years to maximise heat detection, reflecting the €250 cost associated with every missed heat.
Heat detection aids include tail paint, teaser bulls with chin-ball markers, activity monitoring devices attached to the legs or neck of cows and scratch cards. Fit cows will express signs of heat.
To maximise the herd submission rate you will need good old fashioned observation as well as heat detection technology. Three 20-minute observation periods during the day and evening should do the trick.
Various ov-synch programmes have been promoted which do increase submission rate over a concentrated period when compared to the figures achieved by most farmers detecting natural heats.
However, Teagasc's Donagh Berry has warned of a risk of breeding more cows in the future with poor ability to express heat naturally.
In conclusion, focus on keeping your cows fit for the breeding season to maximise the opportunity for heat detection.
Dr Dan Ryan is a bovine reproductive physiologist and can be contacted at www.cowsdna.com