Farmer s GuidaNCe: NBA

Transcription

1 Farmer s GuidANCE: Mandatory BVD Screening 2012 NBA

2 WHAT YOU MUST DO Breeding herds: If you are a keeper of a breeding cattle herd in Scotland, you are required to screen your herd each year for BVD (bovine viral diarrhoea). You must screen your herd using one of the acceptable methods of testing by 1st February Your test result will tell you that your herd is classed as either; negative (meaning there is no evidence of active BVD infection in your herd based on the samples submitted), OR not-negative (meaning a laboratory or vet cannot give your herd a negative status). Non-breeding herds: If you have any other type of cattle herd, such as a finishing herd, then any calves that are born into the herd must be tested for BVD by blood or ear tissue tag test* within 40 days of birth or earlier if the calf is being sold before this. *See p. 5 for more information on the ear tissue tag test.

3 WHO SHOULD READ THIS? Every cattle keeper in Scotland. It is particularly important for cattle keepers who manage breeding herds. WHAT IS THIS GUIDE FOR? This guide explains; What you must do to comply with the BVD Order How we plan to eradicate BVD in Scotland. What you should do after your screening test. What BVD (bovine viral diarrhoea) is and how it works. DO I NEED TO READ IT ALL? No. However, at a bare minimum, you should read the What you must do section. It is recommended that you read Part One (p. 2), which tells you what you need to do to comply with the new regulation and Part Two (p. 3) which details the testing methods you may use. There is also a summary flowchart in the inside of the back page. PART 1: What The BVD Order 2012 Means For You Page 2 PART 2: Testing Methods Page 3 PART 3: Your test result and herd status Page 13 PART 4: What is BVD? Page 18 PART 5: Myth Buster Page 22 1

4 PART 1 WHAT THE BVD ORDER 2012 MEANS FOR YOU BVD is a serious infectious disease of cattle which industry, veterinary science and government have agreed to work together to eradicate. This part describes what you must do to comply with the legislation. Failure to comply is not a cross-compliance issue and will not affect your CAP payments, but it would be a criminal offence under the Animal Health Act A breeding cattle herd is a herd in which: Breeding is expected to take place and no steps are taken to prevent or minimise the chances of such breeding. Starting by 1st February 2012 (please note that tests done from December 2011 still count, see p. 12): If you have a breeding herd; Screen your herd for BVD using one of the acceptable testing methods listed in Part Two; and, Arrange with your vet for samples to be sent to a designated laboratory, a list of which can be found at: If you have any other type of herd you must; Test any calves that are born within 40 days of birth or earlier if the calf is being sold before this by submitting sample(s) to an approved laboratory, a list of which can be found at: 2

5 PART 2 TESTING METHODS Breeding Herds You don t have to individually test every animal in your herd to find out if you have BVD. Instead, you can do a screening test of youngstock, calves or milk which will indicate if BVD may be present in your herd. Once you have done your screening test the result will tell you and your vet whether you are free of BVD or whether you need to do follow-up testing to find out if there is an active BVD infection in your herd. There is a range of different screening methods from which you can choose. Your vet will be able to provide further advice about which method should be used and whether it is appropriate to test for antibodies to BVD or BVD antigen/virus in your case. You must use one of the following six methods: 1. Sampling calves the check-test Whenever possible for a check test, use Option (a) below. Options (b) or (c) are only for herds that don t have enough 9 to 18 month old calves to test. All of these three tests are for antibody. Before deciding to do a check test, speak to your vet to identify how many separately managed groups you have in your herd. Your vet will decide how many animals need to be tested. 3

6 (a) All calves aged 9 to 18 months Take samples of blood from not less than five calves in the age range 9 to 18 months in each separately managed group (see p. 9). for more information). If there are fewer than five calves in a group, then test all calves in the group. (b) 6-18 months If any of your sample of calves are aged 6-9 months, then take a sample of blood from not less than ten calves in the age range 6 to 18 months in each separately managed group. If there are fewer than ten calves in a group, then test all the calves in the group. (c) Over 18 months and on the holding since birth If you have no calves in either of the above age categories, but only then, can you choose to use the following method: Take a sample of blood from not less than five animals that have been on the holding since birth in each separately managed group. If there are fewer than five animals in a group, then test all the animals in the group. 2. Test all calves the calf-crop test Individually test all calves born in the herd in the past year for virus by blood or tissue sample. You can test the calves as they are born or all at once. Ear tissue tag testing (explained below) can be a particularly useful way to do this and is the only method, apart from Method 3: Test all animals (detailed below) which you may do without advice from a vet or milk recorder. 4

7 Ear Tissue Tags Ear tissue tags are designed to take a tissue sample from the ear whilst tagging the animal. The tissue goes into the labelled capsule when the animal is tagged, which is then snapped off and sent to the laboratory. GINO tag If you want to purchase ear tissue tags then contact your usual ear tag supplier. If they do not stock them they should be able to direct you to somewhere that does. 3. Test all animals in the herd Individually blood or tissue sample all the animals in the herd within that year. This is a test for virus and has the advantage that all the persistently infected (PI) animals (see p. 7 for more information) in the herd can be identified and removed. The farmer may choose 5

8 to tissue tag everything, in which case a vet does not need to be consulted, however, if they choose to take blood samples a vet will need to be involved. If all the animals are negative for BVD virus this will constitute a negative result for that year. This testing method is the most expensive option, but it may suit herds where BVD infection is suspected or herds where no other method is entirely suitable. Important welfare note on ear tagging If you wish to use ear tissue tags you should, if possible, use those that are also the official ID tags, either primary or secondary. Applying additional ear tags can cause welfare problems for cattle. If you decide to use ear tissue tags, make sure you use the correct applicator some may appear to work with other tags but can apply them too tightly, causing pain and leading to infection. 4. Single bulk milk and blood test A representative sample of milk with a contribution from all the lactating cows in the herd on that day AND individual blood samples from any dry cows and in-calf heifers present on that day that have not contributed to the bulk tank. Their milk may be collected separately and added to the single bulk milk sample, or blood may be collected. 6

9 5. Four quarterly bulk milk tests A representative sample of milk with a contribution from all the lactating cows in the herd, taken on four occasions not less than 80 days and not more than 100 days apart, should be tested for antibody. To generate a negative herd status, four consecutive negative samples are required. 6. First lactation milk test A representative sample of milk from each of the cows in the herd in their first lactation should be collected and tested for antibody. This is a useful test in herds where the bulk milk test is considered likely to test positive for antibody due to a past infection with BVD or has tested positive for antibody to BVD. Persistently Infected cattle (PIs) Cows that get infected with BVD in their first four months of pregnancy can give birth to a persistently infected (PI) calf. These PI animals are the major source of BVD infection, as they will have the virus all of their lives and spread it in huge quantities. Many will die within the first year of life, but some can live much longer and may appear normal. Cattle infected with BVD after birth are transiently infected and will normally recover in around four weeks, but do suffer from a reduced ability to fight other infectious disease and are likely to have impaired fertility until they recover. 7

10 Testing options summary table: No. TESTING OPTION DAIRY/ BEEF TEST FOR ANTIBODY/ ANTIGEN 1a 5 animals between 9-18 months per separately managed group Either Antibody 1b 10 animals between 6-18 months per separately managed group 1c If neither above are possible 5 animals 18m+ on holding since birth per separately managed group Either Either Antibody Antibody 2 All calves Either Antigen 3 All animals in the herd Either Antigen 4 Bulk milk plus dry Dairy Antibody 5 Quarterly bulk milk Dairy Antibody 6 First lactation Dairy Antibody Health Scheme members Herds fully participating in the CHeCS (further information on p. 13) BVD programmes meet the testing requirements and so if you are testing for BVD as part of your health scheme membership you need not do anything extra. 8

11 Separately managed groups The correct identification of each separately managed group is critical to the effectiveness of check-testing. A management group consists of those animals that can freely achieve nose to nose contact with all others within the group. The virus relies on PI animals as they spread the virus very efficiently when in nose to nose contact with other cattle. Housing with trough feeding will ensure rapid spread whereas spread will be slower among cattle at grass. Because BVD spreads so easily it is not necessary to test every animal in every group. Five animals are sufficient providing the following conditions are met:- All the animals in the group have been together with close contact for at least two months. They will have had nose to nose contact during that period. You must consult a vet when identifying the separately managed groups in your herd and before choosing animals to be tested. The second point about nose to nose contact is important when deciding about housed animals. Animals either side of a central passageway for example are separately managed groups. 9

12 Samples All samples must be sent to a laboratory approved by the Scottish Government. A list of approved laboratories can be found at: If you want to use either of the methods below: Test all calves; using the ear tissue tag test. Test all animals in the herd; using the ear tissue tag test. Then you must submit the following information with the sample to the approved laboratory: Your name and address. Your vet practice s name and address. The CPH number for the Holding on which the herd is kept. The date samples were taken. Which testing method (see Part 2) was chosen. The full 12 character official UK ear tag numbers for all the animals which were tissue tagged. An example form (the Farmer s Submission Form) that you could tear off and use if you want to submit sample(s) to an approved lab is at p. 25. If you need more copies of this form please go to the website at: or it can be photocopied. 10

13 Herd status The laboratory will tell you what your herd status is. It will either be negative or not-negative for BVD. The lab to which you submit your samples will also pass on the resulting herd status to the Scottish Government. In addition to this they will report individual cattle ID numbers for every animal tested for virus, and indicate whether that result was positive or negative. We will presume all cattle testing positive for antigen are PI animals until proved otherwise by a future test, or unless the laboratory can record with confidence that the result suggests transient infection. The BVD Order does not compel you to do anything else apart from the screening test. However, once you have received your herd status we would strongly encourage you to take action if it is notnegative. If you have BVD then your herds productivity is being compromised and you will be losing profits as a result. The status of negative or not-negative applies to an entire CPH. If there is more then one herd on the CPH and any herd is notnegative, then that status will apply to the whole holding. However, we are looking at finding a way for a herd to retain it s negative status even if another herd on the holding was not-negative. This would only be allowed if there was sufficient biosecurity between herds. We will provide more information about this by December

14 Please note that herds carrying out the quarterly bulk milk tests will get no herd status until after the first three quarterly tests are completed providing they are negative. Only after all four quarterly tests are negative will a negative status be allocated. If any of the four tests is not negative, a not negative status will be allocated immediately. Non-breeding herds If you do not have a breeding herd then you only need to test for BVD whenever you have a birth in the herd. If you are testing a calf under one month old you should use an official ID tag that takes a tissue sample these are available from most ear tag suppliers. If you are testing a calf over one month old, you may use a blood or ear tissue test. The sample should be sent to an approved laboratory and tested for virus. You may not move a calf before it has been tested. Testing period The testing period of screening runs from 1st February 2012 to 1st February However, any tests done from December 2011, before February 2012, which was the original start date will still count. 12

15 PART 3 YOUR TEST RESULT AND HERD STATUS My result was negative. What now? This is good news as it almost certainly means your herd was free of BVD on the day it was tested. But unless you are vigilant, your herd could become infected. A good way to keep BVD out of your herd is to join a Cattle Health Certification Standards (CHeCS) scheme, such as the Premium Cattle Health Scheme (PCHS), or the HiHealth Herdcare scheme. You should speak to your vet about these, or visit the website below for more information about what health schemes are available: CHeCS Cattle Health Certification Standards Website: info@checs.co.uk Telephone:

16 There are three main ways that your herd could become infected with BVD: Bringing/buying cattle in If you buy cattle in, or bring in a bull, you should make sure that you are not bringing BVD into your herd. You can do this in a number of ways; Only source cattle from farms that are CHeCS-accredited BVDfree. Only buy cattle at BVD-free sales at markets. Only buy cattle that are individually certified virus-free and vaccinated. Only use bulls that are individually certified virus-free and vaccinated. If not, isolate, test and if the test is negative then vaccinate. Isolate any cattle you bring in, that are of unknown BVD status, from the rest of your herd and have them tested. Only put them into your herd once you know they are clear. Ask for a written declaration to ensure the animal/animals are BVD free. Contact your vet for further advice. Trading You can still trade as normal but are encouraged to do so responsibly i.e. by not buying or selling animal/s that may be 14

17 persistently infected. If you require further advice please contact your local market. Over the fence BVD can be spread by nose to nose contact across fences. If you have a neighbouring cattle farm and don t know their BVD status you may want to ensure there is at least a 3 metre gap that prevents nose to nose contact between the two herds. Vaccination In many cases vaccination is an effective way of protecting your herd from disease. However, it is important to understand that while vaccination may dampen the infection of BVD it will not eradicate BVD, either from a herd or nationally. PI cattle are so highly infectious that they will continue to spread BVD even if the herd is vaccinated. It is vital that the vaccine is administered exactly as instructed on the data sheet. Normally this means giving two doses at a set number of days apart and then a booster 6/12 months later. If you don t follow the instructions, your herd will not be properly protected. Your vet can advise you on the proper way to store, handle and administer the vaccine. My result was not-negative. What now? Firstly, a not-negative result doesn t mean you definitely have BVD in your herd. It can mean that cattle in your herd have been exposed to BVD in the past and have recovered. Or it can mean that the laboratory test result was uncertain. 15

18 Until December 2012, the result you get won t impact on your ability to go about your normal business. But from 1 December 2012 there will be consequences to having a not-negative herd status. A not-negative result means you should take action. We recommend that you should do more testing through your vet. There are many ways of doing this, and again it might be that you don t need to test every individual animal. You should speak to your vet who will be able to advise you. Your vet can also change your status if they are satisfied that adequate follow up testing has taken place. Once they have completed the online CPD course (see link at uk/bvd) they will be able to contact the BVD database and change the herd status of a specific farm, herd or perhaps CPH from notnegative to negative. If you do have a BVD infection in your herd, the most important thing is to find out if you have any PI animals. If you do have a PI animal, it should be culled or sent for slaughter as quickly as possible. PI cattle may enter the food chain so you will be able to get market value. 16

19 The sooner you identify and remove any PI cattle, the sooner you will be able to achieve a negative status. This will also protect your herd from further infection and poor performance. PI cattle should never be sold other than for slaughter, and should never enter a market. It is the intention of Scottish Government to make the sale of a known PI animal an offence in the future. In the meantime, selling a known or suspected PI animal may leave you exposed to damage claims if it causes an outbreak in the buyer s herd. BVD is a major cause of mortality, abortion, infertility and poor condition. BVD is present in around 40% of herds. 17

20 PART 4 BVD: WHAT IT IS AND HOW IT SPREADS Bovine viral diarrhoea (BVD) is a widespread disease of cattle causing various symptoms including abortion, stillbirths, diarrhoea, pneumonia, poor condition and a lowering of resistance against other infections. It is a serious infectious disease of cattle and can be fatal. BVD is caused by a virus (BVDV) which is spread by persistently infected (PI) cattle which constantly produce and shed the virus in saliva, nasal mucus, faeces and semen. PI cattle can only have acquired that infection in the first third of foetal life. Approximately one of every 100 youngstock in Scotland is PI. They are always virus positive and don t produce antibody against BVDV. They can die of mucosal disease at any age. Some survive into adulthood and pose a real threat. A PI bull can wreak havoc if added to a susceptible herd, and if a PI cow has a calf it will always be PI. Most die as calves but a few live much longer and many PI animals appear normal. The photo on the left shows two calves of the same age, but the one on the left is a PI. Picture: Prof Joe Brownlie, RVC. 18

21 Around two-fifths of all herds in Scotland have signs of exposure to BVD. Estimates are that there are between 2,000 and 4,000 PI animals. It is important to note that PI animals can also look perfectly normal and in very good condition, though this is rare (see photo below). Picture: Catriona Ritchie, SAC Therefore, if you get a not negative result showing evidence of PI cattle within your herd you cannot just cull out any animals that look in poor condition and assume that will solve the problem. What are antibodies, antigen and virus? The laboratory tests for BVD look for BVD virus/antigen, or for antibodies. Antibodies are created when the animal encounters BVD virus, so testing for antibodies shows if BVD may be present in the herd. This is the principle on which the check-test is based (see p. 3). Antigens are the part of the virus that an animal reacts to and forms antibodies against. A test is done for antigen or virus when you are looking for PI animals, for example the calf crop test (see p. 4). 19

22 Testing a sample of animals for antibodies in each separately managed group enables you and your vet to work out if more testing needs to be done, and if so, where. Follow up testing will often be for virus or antigen because you are looking for PI animals. Testing for virus or antigen will tell you if that individual animal has BVD. How common is BVD? A 2007 survey by the Scottish Agricultural College (SAC) showed around 40% of herds have signs of exposure to BVD. We believe around a quarter of beef herds and up to half of dairy herds have evidence of exposure. Why eradicate BVD? Eradicating BVD would be worth up to 80 million over ten years to the Scottish cattle industry. Scottish Government economists have calculated the benefits of eradicating BVD for four average types of farm: Annual benefits after eradication: Dairy 15,800 LFA Specialist beef 2,400 LFA cattle & sheep 1,800 Lowground cattle & sheep 2,400 (LFA Less Favoured Area) 20

23 An average dairy herd would be 16,000 better off every year, and an average beef unit around 2,000 better off each year. Where can I get more information? The best source of advice and information is usually your vet. If you are in a health scheme you will be able to access specialist advice through them. For more information on the Scottish Government s eradication plan or the screening requirements, you should contact the Scottish Government at bvd@scotland.gsi.gov.uk, or For more information on BVD generally, you could visit the Scottish Government s website at which explains more about the disease and has links to academic sites. If you are not sure what method to use to screen your herd, the best source of advice is your vet. 21

24 PART 5 BVD MYTH BUSTER 1. Got BVD? Don t worry, you can just vaccinate. FALSE vaccination does not deal with PI animals. They are too highly infectious and will still be able to spread infection potentially creating yet more PI calves. A PI animal will always have a PI calf. 2. You should keep a PI animal on the farm so that your animals are not naive through natural vaccination i.e. the idea of PI parties. FALSE PI animals are highly infectious and should be culled as soon as they are identified. BVD causes significant losses on herds that have it; through transient as well as persistent infection. An animal that is transiently infected will suffer lower immunity and increased susceptibility to other diseases as a result. 3. The government is making vaccination compulsory/the government is banning vaccination. FALSE Vaccination will continue to be an important part of controlling BVD for many herds, but it is a decision to be taken between keepers and vets. 4. You can t get rid of BVD, because of transient infection. FALSE The evidence is overwhelming that removing the persistently infected animals will stop the disease from circulating. Transient infection will fizzle out on its own. 22

25 5. There s no point in getting rid of BVD, because my herd will be re-infected by sheep/deer. FALSE Sheep can carry BVD and can re-infect your herd, but only if they have been in contact with cattle with BVD in the first place. Removing the source of infection the PI cattle will reduce BVD among sheep. Also, transmission from sheep to cattle is very weak, so only a small number will be unlucky enough to get re-infected this way. To be sure though, you should keep breeding cattle away from sheep. Deer can carry BVD, but we ve no evidence to think this is a serious problem, and again, removing PI cattle will remove a major source of infection for deer. 6. It s impossible to eradicate BVD from my herd I ve been trying for years. FALSE The vast majority who have followed a CHeCS scheme have got rid of BVD in under 2 years. If you test to find your PI cattle, slaughter them, buy in only BVD-free cattle or isolate and test them, test your calves for 2 years, and exercise good biosecurity, you should get rid of a BVD infection in under 24 months. All the studies show that the benefit to your profits will far outweigh the cost of getting rid of BVD. 7. I ve got a PI animal, but it looks alright so I don t need to slaughter it, I ll just finish it. FALSE Very few PI animals ever reach a good slaughter weight. You will only waste money trying to feed it. While it s on your farm it is a significant disease risk to the rest of your herd. It s always better to send it for slaughter immediately. 23

26 24

27 FARMER S SUBMISSION FORM Holding Number (CPH): / / Name VETS DETAILS: Address Name Address Postcode Tel: Fax: Postcode Tel: Fax: Date samples were taken: / / Are you a health scheme member? Yes No Declaration by Keeper These samples are intended to constitute a mandatory annual screening test for BVD for my herd. Signature: Date FOR LABORATORY USE: Date of receipt: Initials: Reported Vet Lab Ref No: No of samples Checked: Invoiced Databased 25

28 Calf Screen Option: For a calf screen, all calves born on the farm between 1st February 2012 and 1st February 2013 have to be screened for BVD virus (please copy this form for further calves as necessary or download from the website, see below). Please discuss the options for this with the testing laboratory where necessary. Which screening method have you selected? TEST ALL CALVES; using the ear tissue test. (now please select one of the options below) This lab submission fulfils the above method in full. This lab submission fulfils the above method in part. TEST ALL ANIMALS IN THE HERD; using the ear tissue test. This lab submission fulfils the above method in full. This lab submission fulfils the above method in part. Official ID Tissue Tag Number (if different) Laboratory Reference BVD Virus Please tick this box if you do not give permission for samples and information you submit to be shared with Scottish Government appointed research providers to support BVD eradication. 26

29 This guidance has been created by The Scottish Government s BVD Team with content and advice from George Caldow of SAC, Peter Nettleton and partners from the livestock industry, veterinary profession and scientific bodies. Further copies of this guidance are available from: BVD Policy Team Scottish Government P Spur Saughton House Broomhouse Drive Edinburgh EH11 3XD Tel: Fax: bvd@scotland.gsi.gov.uk WEBSITE: 27

30

31 [SUMMARY FLOW CHART] Cattle Keepers Keeper of Breeding Herd Keeper of Non-Breeding Herd Dairy Herd Beef Herd Consult with your vet and choose from any of the testing methods from p. 3. Send the samples to an approved laboratory. Consult with your vet and choose from any of the testing methods from p. 3 excluding the DAIRY ONLY options. Send the samples to an approved laboratory. Blood or tissue tag test for BVD virus any calves born within 40 days of birth or earlier if the calf is being sold before this. Send sample/s to an approved laboratory. Herd status will be negative or not-negative (laboratory will tell you) Negative Not-Negative Maintain status through biosecurity. Speak with your vet to find a way to change your status.

32 Crown copyright 2012 ISBN: This document is also available on the Scottish Government website: For more information go to APS Group Scotland DPPAS12125(01/12) w w w. s c o t l a n d. g o v. u k