Series Two: Episode Two - Mastitis in Dairy Herds: Transcript
Sam Thom: Livestock productivity is hugely influenced by animal health and welfare and in dairy herds mastitis is one of the biggest challenges to productivity. It’s a complex problem and can cost the producer £1,000s a year. My name is Sam Thom and for this Scottish Agricultural College podcast I’ve come to meet vet Helen Carty at the SAC’s veterinary surveillance centre in Ayr and to get the best advice on how to tackle the problem of mastitis. But what is it first of all?
Helen Carty: Mastitis is just inflammation of the udder and it will mean that the milk produced by the cow will not be of such good quality. It’ll spoil more quickly and it will decrease the amount of milk produced over all as well, if you have inflammation in the udder.
ST: And it’s contagious or it can be picked up from the environment? How do they contract this?
HC: There are different bugs that can cause mastitis. There are probably five main bacteria that are responsible for the majority of the cases of mastitis. And some of these will be picked up from the environment. Bugs such as ecoli, they’ll be picked up from dung, the manure, either in the bedding of cows, or pasture, round about gateways, but there are other causes of mastitis that are contagious. Bugs such as staph aureous (staphylococcus aureus) can be spread form one cow to the next during the milking time. So it can be spread on the milking liners, or on people’s hands or on common cloth that may be used in the parlour.
ST: So if you can establish the bug you have a good clue as to what the root cause is?
HC: Yes, you would have to gather a lot of data to have enough evidence to know the main root cause, but by looking at records, by looking at clinical cases of mastitis, and looking at cell counts also that could lead us to determining whether it’s predominantly an environmental problem or a contagious problem. Collecting milk samples can also help with that. So if a farmer had a cow with a clinical case of mastitis if he took a milk sample from that and submitted it to a lab for bacteriology then the type of bug isolated might help us work out why that cow got that infection.
ST: And of course farms they may notice seasonal variations?
HC: They may do, particularly with environmental causes of mastitis, perhaps when cows go out to grass they may see an increase in cases, or perhaps when cows are housed there may be an increase, so it’s really about looking at records to try to pick up trends to try to see where we can make a difference, where we can improve management perhaps to decrease the levels of mastitis.
ST: Now, of course, mastitis is a problem – it’s always there. But how does the farmer know when it is a problem that he really needs to focus on?
HC: No dairy farm will have zero cases of mastitis. It’s always going to be a concern. So a farm may have clinical cases of mastitis when they have sick cows, and the milk would look abnormal, there may be clots, discoloration of the milk. On every farm there will also be some cases of sub-clinical cases of mastitis when the milk itself looks normal and the cow is well in herself. But the cell count reading is high.
Now the cell counts are really white blood cells we’re looking at that are produced by the cow when she’s trying to fight infection. And so if a farmer has a bulk cell count reading consistently over 200,000 cells per millilitre that would suggest there is an underlying problem with mastitis. And so that would be a good reason to get your vet in to look at records and to discuss things to see what could be improved. If a farmer had more than a quarter of his cows, of individual cows with cell counts over 200,000 as well that would be an indication that things could probably be improved. You could probably put in measures to decrease that level.
ST: And these are records that the farmer will be keeping himself?
HC: It would be good practice to do so and we would certainly encourage all farmers to make a note of whenever they have a case of clinical mastitis. Most farmers will be able to extract that information from their medicine book. Because if they have had a case of clinical mastitis they will have treated her, treated the cow with an intra-mammary anti-biotic. So we would expect that information will be available to look at. Many farmers will also get monthly cell count recordings done so every single cow in the herd will have a sample taken every month, and we can look at trends in the cell counts to see if there are problems arising. We can look to see if cows are going from having a cell count below 200,000 to over 200,000, how many cows are picking up new infections every month, we can also use the cell count records to see if dry cow therapy has been effective periods or to see if cows are acquiring new infections during the dry period.
ST: Okay so, just to recap, what should a farmer do when he or she encounters incidences of mastitis which they feel in terms of quantity are something to take notice of?
HC: I think the most important this is to keep good records – regularly keep good records, and review these regularly with your vet so that we can monitor things and see where improvements can be made. Basically we want to decide what the problem is. If you imagine there are several gold standard procedures that should happen on all dairy farms, but we want to make sure that we target the advice. The advice should be tailor-made for each individual farm, so that if we can look at the records with the vet then we can come up with the best approach.
ST: And so Helen the message is don’t accept that high levels of mastitis are inevitable and do something about it and save money and increase your production.
HC: Certainly, and challenge your vet to help you because that’s what they’re trained for.
ST: Okay, Helen here at the veterinary surveillance centre in Ayr, thanks very much.