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HFV News MARCH 2021

In this issue…

  • Who's in your bull pen?
  • Ischaemic Teat Necrosis (ITN)
  • Counting the cost of BVD
  • Bulk tank TB tests - can you help?
  • Lepto Boosters

Who's in your bull pen?

From the 1st of January 2021 it has been compulsory for all pedigree Holstein bulls to be genomically tested in order to be registered.

Whilst there is a small cost involved in this (£32.50), it provides a great deal of information about the genetic merit of the bull that you choose; will make it easier to select the right bull for your herd, and choose the right females to breed him with.

Young bulls with only pedigree information and no genomic testing can only ever achieve a trait reliability of 49%, whilst a genomically tested young bull usually achieves a trait reliability score of 60 to 70%.

In terms of the information this provides about the bull’s offspring, this is equivalent to having data from 10 milking daughters - something that would take years using the traditional progeny testing bull proof method.

Young bulls can be tested as soon as they are born, and DNA testing is carried out using either a tissue sample from an ear notch, or by a hair sample so handling and stress to the bull is minimal.

Get in touch if you want any more information about getting a genomic proof from your stock bull.

Ischaemic Teat Necrosis (ITN)

Ischaemic teat necrosis (ITN) is an emerging disease of the teats and udder that causes extreme irritation to the animal, and often leads to excessive licking and self-trauma. This can often unfortunately lead to the animal removing the teat entirely.

Advanced ITN case with traumatised teat and evidence of bite marks on teats / udder

Freshly-calved heifers are the most commonly affected members of the herd, with 80% of cases being recorded in this group. Research is starting to show there are a huge number of inflammatory cells in the affected teats but no common risk factors found as yet - all breeds/yields/systems seem equally affected. There are no known effective cures; antibiotics seem ineffective against ITN, and it commonly leads to the animal being culled.

There are a number of other diseases of the teats that can appear similar, such as Bovine Herpes Mammilitis - but these other conditions rarely cause as much irritation as ITN and clear up over time. The incidence of ITN appears to be increasing in the UK, and there are both serious welfare and economical impacts for affected herds.

Cases are usually first noticed when an area of dark, dry and crusty skin appears on the inner side of the base of the teat where it joins the udder; this then spreads over the rest of the teat and surrounding udder skin. The cause(s) are not fully understood, although there is some evidence to suggest the involvement of Treponemes - the same bacteria associated with Digital Dermatitis. The lesions do not directly cause mastitis, but an inability to milk the quarter due to the painful teat can lead to mastitis as a secondary effect.

Preventing / Dealing with ITN

  • Make sure you routinely check the front of teats as ITN can go unnoticed here in the early stages, and this is the part of the teat most commonly affected
  • Heifers seem most at risk so make sure the teat skin in these animals is supple and healthy by using a good coverage of a high emollient post-milking teat dip
  • If on sand bedding move the cow to a straw yard - there is suspicion that the abrasive properties of sand on the teats during milking may be a risk factor for ITN
  • Some farms report improved recovery rates with the use of creams such as Sudocrem, Udder Grease and Salicyclic Acid (Aspirin) powders
  • If there is extreme irritation with excessive licking and self-trauma, use a couple of old tyres as a collar to prevent the animal from reaching her teats

Ongoing Research

There is a PhD research project currently being undertaken by the University of Liverpool to investigate the risk factors, causes and potential treatments for ITN. If you have any suspect cases please get in touch with Paula or Tom as the PhD students are keen to know about cases and collect samples to help with their research.

Counting the cost of BVD

BVD is a viral disease of cattle that causes pregnancy loss in breeding females, the birth of persistently infected calves "PI's" and severe immunosuppression if you have one of these PI animals mixing with your herd.

BVD is controlled by a combination of strict biosecurity to prevent incoming disease, vaccination to protect the breeding herd, and then ongoing scheduled monitoring to check that there is no active infection in the various groups on the farm.

An early pregnancy loss - a common finding in a BVD infected herd

We proactively check for signs of active BVD infection by looking at your homebred youngstock to see if they have been exposed to BVD virus using antibody "check testing". If your youngstock are negative for antibodies this means they haven't come across BVD and it's unlikely you have recent, active infection in the herd, and we simply schedule in and repeat this testing as each youngstock group hits 9 months old.

If we find any evidence of BVD antibodies in your youngstock then we need to act quickly to find out how widespread the infection is, check your vaccine protocols have no immunity gaps and check for any possible PI's in your youngstock.

BVD is incredibly infectious and can spread from visitors or neighbouring stock that have close contact with your animals, or can be bought in in purchased cattle so it is essential you limit visitor access to your cattle, have secure 3 metre double fenced boundaries, only buy in from accredited BVD free stock or request for incoming animals to be BVD tested before arrival.

Remember BVD virus can survive for short periods in the environment too - environmental survival depends on temperature and moisture levels: BVD can survive in slurry for 3 weeks at 5°C and 3 days at 20°C. Please make sure ANYONE contacting your cattle are clean, their equipment is clean, and they scrub ON to your farm, as well as off: have fresh FAM30 ready made in a boot dip for them to use. The same goes for shared slurry equipment - make sure these machines are clean before coming on farm.

Bulk tank TB tests - can you help?

A request for bulk tank milk samples to help with development of a new screening test for bovine TB

Everyone is familiar with the traditional tests for bTB; skin or gamma bloods are the mainstay of the current TB control policy in the UK but there are new tests in the pipeline too.

The Enferplex Bovine TB test looks for antibodies to TB and can be used on blood or milk; both as individual samples and bulk tank samples. The blood sample has already been approved for use by the OIE, and research is ongoing into how a bulk tank screen could be used to detect milking cow reactors.

In the early stages of validating a new test, researchers need to check the sensitivity (do we believe a positive) and specificity (do we believe a negative) and this is where some of you might be able to help.

Testing Requirements:

We would take a bulk tank sample on day one of the TB test, then if any reactors are disclosed in the milking herd on day 2, that bulk tank sample will be sent off at no cost to you and tested for TB antibodies. The results of the bulk tank test will not affect your TB test results, testing intervals or requirements for any additional testing, but will help to check if a bulk tank screening test is able to reliably detect the presence of reactors in a milking herd and could be part of a solution in the future of TB control.

Lepto Boosters

Lepto vaccines are usually boosted each Spring before turn out so that cattle have maximum protection for the grazing period.

Don't forget, overwintered sheep can be silent shedders of Lepto - they aren't affected by it, but will shed it onto grazing via infected urine and that pasture will remain infective for up to 2 months after the sheep have left.

Make sure boosters are in and pastures grazed by sheep have had at least 2 months rest before cattle are turned out for 2021.

If you are not vaccinating, we can check for signs of exposure in the herd by looking at bulk tank antibodies, or blood samples in a cohort of milking heifers - this way we keep an eye on infection pressure in the herd.

Leptavoid-H Vaccine

Leptavoid-H is a 2ml dose, given under the skin. Initial start up is 2 doses given 4-6 weeks apart followed by a 12 month booster.

Get in touch if you want more information or for 2021 prices.

GET IN TOUCH:

Paula: 07764 747855 paula@haywoodfarmvets.com

Tom: 07837 291097 tom@haywoodfarmvets.com

Enquiries: mail@haywoodfarmvets.com

Website: haywoodfarmvets.com

Open hours: M-F 08:30 - 16:30

Out of Hours: 07398 743095

Created By
Paula Scales
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