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19th September, 2014

Breeding management in the Suckler Herd.

It has been widely publicized that there has been a steady decline in reproductive performance in the dairy herd population over the past twenty years. It may come as a surprise to many that the average calving interval for the Irish suckler cow population is similar to that encountered in the dairy herd.

Reproductive Performance in the Suckler Herd

suckler cows1However reproductive performance in the suckler herd is impaired for radically different reasons that encountered in the dairy herd. Over the past two years CowsDNA have collected reproductive data from dairy and beef cattle in both the North and South of Ireland. We have adapted the use of ultrasonography of the reproductive tract (USART) to create a unique system whereby an assessment can be made of both individual cow and herd health status. This data is currently being analysed in conjunction with Teagasc and ICBF and will be made available for future development of the industry.

In my opinion there are three primary constraints placed on the suckler herd integrating optimum reproductive performance.

  1. Cows are semi-starved in the latter part of gestation to avoid difficult calvings.
  2. Semi-starvation post calving to avoid excess milk production and consequent scouring among calves.
  3. Failure to correctly match cows with the sire used whereby poor quality suckler cows are bred to sires with an exacerbated risk of dystocia at birth.

 

Scanning using our unique USART technology

Results from scanning using our unique USART technology reveal that the primary reason for delayed return to heat cycles post calving in the suckler cow are associated with dystocia at calving, poor body condition score (BCS) at calving, excessive BCS loss post calving and poor diet management. A suckling effect is commonly offered as a primary cause of delayed return to cyclicity in particular among first calvers. However in our experience suckler cows managed to maintain BCS precalving, minimal dystocia and a BCS loss of no greater than 0.5 on the first six weeks after calving will have normal uterine involution and return to oestrous cycles assessed using USART.
This data is supported by the fact that these cows have a shorter calving to pregnancy interval. This all makes economic sense but we as cattle breeders all desire to produce weanlings with excellent weight and confirmation for age figures. The focus has to change whereby sires are used that will not result in dystocia among cows managed to maintain BCS in the latter phase of pregnancy.

Correct Type of Maiden Heifers

Suckler Cow2There is also a need to select the correct type of maiden heifers to become dams in the suckler herd. Excessive selection for muscle index and associated poor pelvis area have resulted in an increased incidence of delayed puberty, poor reproductive performance and increased dystocis. The current emphasis on first calving at two years of age dictates that maiden heifers cannot get health setbacks during this period which unfortunately are too frequent. Health management programmes entailing biosecurity, health monitoring, vaccination anthelmintic treatments and nutritional management are essential to achieve the desired status after calving at two years of age.

The use of AI has been mainly restricted to suckler herds while housed indoors during the winter months. When cows are put out to grass in the spring it is frequently to an outside farm where access to handling facilities is minimal. Farmers neither have the desire not the time required to spend watching cows for visual signs of heat. There is therefore the standard introduction to a stock bull to the herd. This literally places all your eggs in the one basket in terms of genetic potential of the progeny risk of infertility in the bull and dystocia at birth.

AI could be used successfully at the onset of the breeding season by using USART technology. This entails the scanning of all cows calved greater than 14 days at the onset of the breeding season. A programme can be put in place whereby those cows fit for service can be synchronized and bred over a short time period. In addition those cows not fit for service can be managed to reduce days open when running with a stock bull.

The stock bull is a necessity for the suckler herd to mop up those cows failing to settle to AI. However please ensure the bull you use is fit for purpose. Simple semen tests will evaluate semen fertility. Ensure your bull is capable of successfully serving cows. Studies show that 10 % of bulls are either subfertile or infertile.

embryonic_mortality_photoEmbryonic mortality for either genetic or non-genetic reasons will prevent cows returning to normal heat for up to nine weeks depending on the stage of the embryonic mortality. It is essential to scan cows using USART technology prior to the end of the breeding season and ideally 6-8 weeks into the breeding season. There are several reasons for this approach.

  1. Accurately age pregnancies.
  2. Sex pregnancies greater than 51 days of age.
  3. Identify cows with embryonic mortality to reduce days open.
  4. Manage late calving cows to reduce days open.

In conclusion, reproductive performance in the suckler herd could be dramatically improved using a few simple steps.

  1. Match sires to your cows
  2. Do not starve cows post calving to avoid scouring in calves
  3. Match sires to your cows
  4. Avoid selecting replacements with excessive muscle index and poor pelvic size
  5. Use ultrasonography ( USART) technology designed by CowsDNA to maximize reproductive performance

Dr. Dan Ryan is a bovine reproductive physiologist. More details on his company can be found on www.cowsdna.com