Farm Ireland
Independent.ie

Monday 19 February 2018

It is now time to evaluate the dairy herd's reproductive performance

Dr Dan Ryan

We are now between eight and 12 weeks into breeding programmes for spring calving in 2014. The seven-day heat wave is now a distant memory. However, it did enable excellent silage preservation for next winter.

The inclement weather in latter weeks has made grazing conditions difficult with a consequent decrease in dry matter intake from grazed grass.

It is time to evaluate the primary driver of your dairy business, which is the reproductive performance of the dairy herd.

One tool worth using is Ultra-Sonographic Assessment of the Reproductive Tract (USART) scan technologies, which integrates existing bioinformatic data pertaining to the dairy herd with USART reproductive data to generate a report on reproductive performance.

How does this work?

Cows DNA have developed a ScanMan system where the cows can be scanned to determine their reproductive status with the aid of having 'days calved', 'days served' and 'age' of the cow appearing on the screen as we conduct a USART scan.

This information can be attached to the passport of each cow for future reference on subsequent USART scans.

A copy of the USART scan results can then be emailed to your computer in a format which can be integrated into your farm software package.

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This technology replaces the "Cornflakes box" for data recording with an in-depth analysis of reproductive per-formance on your dairy herd.

At this stage of your breeding programme, the USART scan can identify:

* Whether your April and May calvers are cycling and fit to go in calf;

* Whether you are missing repeats to AI services or not;

* Whether there are reproductive problems among those cows fit for AI;

* Whether there are embryonic deaths preventing cows coming back into heat;

* Whether there are cows carrying twins which will have greater risk of embryonic mortality;

* The accurate ageing and gender determination of pregnancies.

Having identified those cows that are not pregnant, it is essential to get your vet to synchronise heats efficiently as you only have a maximum of two breeding opportunities left in the breeding season.

Remember, missed breeding opportunities cost you €250 per cow and the opportunity cost of culled cows is between €800 and €1,000 per cow.

At this stage of an AI breeding programme I suggest the following: Conduct a USART scan of your herd. Tail-paint cows confirmed pregnant blue, cows less than 25 days served yellow, and cows not pregnant red. It is pointless synchronising heats in cows not fit for breeding.

These include lame cows, cows with poor body condition score and cows with repeated incidences of mastitis and high somatic cell count.

Heats can be induced in the red cows under veterinary supervision. Only those with embryonic mortality, missed repeats, and non-cycling cows which are fit for breeding should be considered for induction of heats.

Remember cows undergoing embryonic mort-ality can take up to nine weeks to return to heat and unless a scan identifies these cows, they are effectively culled from the herd.

Keeping your cows in calf is as important as getting cows in calf. The majority of embryonic mortality in dairy herds is associated with environmental stressors. One of the primary concerns is the high incidence of acidosis experienced by dairy herds at grass in the months of May and June.

However, it is possible to turn around your herd's fertility. And it can be done without resorting to crossbreeding.

I scanned 115 cows for a client last week. This farmer had a tough time getting cows in calf last year. As a result he was very focused on the issue this spring. For this reason, he made sure that the cows were kept well fed all spring.

It worked. After a 10 week breeding season, using only AI, 107 cows scanned pregnant, six were empty and two were served less than 20 days.

Diseases such as Neospora, IBR, BVD and Schmallenberg will result in embryonic and foetal mortality.

There are reliable milk and blood tests to assess the risk of these diseases in your herd. Preventative health management programmes are your primary concern.

In the case of BVD, it is essential to remove all PI animals from the herd. Some farmers have kept the calves in the hope of an early slaughter age. But these PI animals are a major risk of infection for early stage pregnancies which inc-reases embryonic/foetal mortality and the birth of PI calves.

Schmallenberg disease uses the midge fly as an intermediate host for transmission to infect pregnancies between 40 and 120 days.

A vaccine has just been licensed for use in non-pregnant animals, which is too late in most cases for this year's spring breeding programme. Some vets have advised farmers to apply a pour on to all breeding groups which contains anti-fly repellant as a preventative measure against the disease.

It is essential you prevent milk yield drops by any more than 2.5pc among cows which have peaked milk yield in May.

Excessive milk drop is the greatest source of reproductive impairment in the herd. Avoid underfeeding and imbalanced diets by either golf ball grazing or stemmy grass.

Leptospirosis and IBR will also result in milk drops. Healthy cows in a positive energy state are your primary concern to maximise immunity and prevent embryonic mortality.

Dr Dan Ryan is a breeding management consultant and can be contacted at CowsDNA.com

Irish Independent