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14th December, 2017

GETTING AND KEEPING YOUR COWS IN CALF

Grass_FieldWe are now between 8 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 DMI from grazed grass.

 

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

The best approach is to avail of USART *scan technologies which integrate existing bioinformatic data pertaining to the dairy herd with USART reproductive data to generate a report on reproductive performance. How does this work? Reprodoc have developed a ScanMan system whereby 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 of the cows. This information can be attached to the passport of each cow for future reference on subsequent USART scans. Upon completion of the USART scan, Bluetooth technology enables a printout with a breakdown of the scan into various categories of non-pregnant and pregnant cows. A copy of the USART scan results can also be emailed to your computer in a format which can be integrated into your farm software package.

This technology removes the day of the “Cornflakes box” for data recording to an in-depth analysis of reproductive performance on your dairy herd. Your time is valuable and accurate reporting is essential for both nutritionists and vets. The USART scan will identify the nature and scale of the problem preventing optimal reproductive performance.

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

• Are your April and May calvers cycling and fit to go in calf.
• Are you missing repeats to AI services.
• Are there reproductive problems among those cows fit for AI.
• Are there embryonic deaths preventing cows coming back into heat.
• Are there cows carrying twins which will have greater risk of embryonic mortality.
• The accurate ageing and gender determination of pregnancies.

Having identified those cows which 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.

tail_paintingAt this stage of an AI breeding programme might 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 synchronizing heats in cows not fit for breeding. These include lame cows, cows in poor body condition score and cows with repeated incidences of mastitis and high somatic cell count. USART scan technologies will identify these cows.

Heats can be induced in the “red” cows under veterinary supervision. Only those cows with embryonic mortality, missed repeats and non-cycling cows which are fit for breeding based on a USART scan should be considered for induction of heats. Remember that cows undergoing embryonic mortality can take up to 9 weeks to return to heat unless a USART scan identifies these cows, they are effectively culled from the herd.

Keeping your cows in calf

In excess of 90pc of your cows begin with a pregnancy status after breeding. However, because of embryonic/foetal mortality, we end up with a calving rate ranging from 30 to 60pc. The majority of embryonic mortality occurs prior to day 35 of pregnant when implantation is complete.

The majority of embryonic mortality 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. Management strategies must be put in place to prevent Acidosis as it will impair reproductive performance. Diseases such as Neospora, IBR, BVD and Schmallenberg will result in embryonic and foetal mortality. There are reliable milk and blood tests to access 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. However, these PI animals are a major risk of infection for early stage pregnancies thereby increasing 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 years’ spring breeding programme. Some vets have advised farmers to apply a pour on to all breeding groups which contains an anti-fly repellant as a preventative for the disease.

It is essential that you prevent milk yield drops by any more than 2.5% from one week to the next among cows which have peaked milk yield in May. Excessive milk drop is the greatest source of reproductive impairment in the dairy 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 maximize immuno competence and prevent embryonic mortality.

*USART – UltraSonographic Assessment of the Reproductive Tract.

Dr. Dan Ryan is a breeding management consultant and can be contacted at Reprodoc for further details.

Article written by Dr. Dan Ryan in The Farming Independent July 2, 2013.