As anti-mastitis strategies change, expect to use more herd consultants
By Don Stoneman
The "five-point plan" that veterinarians and udder health specialists have used for three decades to treat dairy cows with mastitis appears to have outlived its usefulness.New mastitis control strategies are on the way, which will likely require more consultation with herd veterinarians to be effective.
The old strategy was a simple recipe for low somatic cell count (SCC) success. "If you did these five things you could expect a low cell count herd," says Dr. Ken Leslie, a professor in the department of population medicine at the Ontario Veterinary College. The five-point system was fairly straightforward, Leslie, says:
* Keep well-designed milking machines maintained and functioning properly;This strategy was most effective against contagious forms of mastitis, says Leslie, but "does not recognize or deal with the new importance of environmental pathogens."
* Clean and dry teats before milking and teat dip afterwards;
* Dry-cow treat every quarter of every cow with a long-lasting antibiotic;
* Recognize clinical mastitis cases early and treat them promptly;
* Finally, cull chronically infected cows.
A new method is now being developed by the National Mastitis Council's research committee, which counts Leslie among its members. But he warns that the new treatments will involve less step-by-step work by farmers, and leave more room for the operator's economic evaluation. And for that he may need help.
Post-milking teat disinfecting with iodine will still be emphasized, Leslie says, as will dry treatment of every quarter of every cow. "But for almost every other recommendation there comes a caveat," he says.
For example, formerly, veterinarians recommended that a cow be treated for mastitis regardless of the stage of her lactation. Under the new procedure, the treatment recommendation will vary depending on her stage of lactation, her age and the type of bug that is causing the udder inflammation. If a cow is only three weeks away from being dried off, the recommendation would be to dry her off early and dry treat her, saving on the cost of one treatment.
Farmers are going to have to decide for themselves what a high SCC cow is costing them in their herds, says Leslie. If a producer is striving to produce milk for the fall market, he may decide to keep a clinically infected cow even if she is a high cell milker. But that same cow may cause more trouble than she is worth if she is producing two-million SCC milk that pushes the bulk tank over the 300,000 cell limit and draws a milk quality penalty.
Plan Now For August Misfortunes
Veterinary scientist Ann Godkin of the Ontario agriculture ministry's Fergus office thinks many farmers were close to the penalty line last year and may go over it in the coming summer. Last August the average SCC in the provincial herd hit its highest level since 1995. For the last couple of years August has been the high month for the year and counts have been drifting upward, rather than down. Godkin thinks that farmers with milk quality problems last summer included relatively intensive managers who normally don't have mastitis, but were aiming to produce more milk for the high fall demand, maximizing possible income from their quota. "They weren't prepared to deal with it," she says.Higher seasonal temperatures appear to be a factor. "I don't predict weather but the long term trends are for it to be warm again next summer," she says. "That can get us into trouble with types of mastitis that we weren't prepared to deal with."
Mastitis becomes costly. First it reduces milk production then quality penalties take a toll. On 25,000 litres of production in a month the first penalty of $3.00 per hectolitre will reduce a farmers income by $750.
Godkin isn't sure what is causing the trend, but she thinks farmers have to act now to arrest it in the summer. Herd managers need to think about what cows they want to be calving in the summer time, and whether those cows will be contributing to the higher cell counts.
Control of contagious mastitis is fairly straightforward, says Godkin, but dealing with environmental mastitis is another story. Farmers who follow standard mastitis control measures carefully are getting frustrated because they aren't seeing their cell counts come down, she says. Unfortunately, there is no single recipe for solving environmental mastitis causing high cell counts.
"I hate to sound like I am plugging veterinarians, but there is no other way around this one," says Godkin. The issues involved with environmental mastitis are just too complex, she says, and solutions will vary from farm to farm.
Housing and management of bedding are critical, as are nutrition programs that reduce stress. It's also important to have access to records such as Ontario DHI and Dairy Comp. "It's likely that a vet can put this all together," she says. "It's hard to tell what will work unless you've worked on a number of farms with the problem."
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Do agricultural antibiotics pose a threat to human health?
By TOM HAMILTON
The use of antimicrobial drugs in farming is under attack. In Europe, agricultural use of many antibiotics has been severely restricted, due to concerns about their potential impact on human health. There is mounting pressure for similar action in North America. If public sentiment against the use of antibiotics in livestock management builds, our beef industry may face restrictions or outright bans on the use of many antimicrobial compounds.What's behind the concerns? The fundamental issue is that the use of antibiotics in livestock may result in antibiotic resistance developing in bacteria which cause disease in humans. These resistant bacteria become difficult to fight since they are not affected by one or more types of antibiotics. If a bacterium were resistant to all classes of available antibiotics, the illness resulting from it would be virtually untreatable.
These are chilling thoughts. But are they science fiction or fact ? In order to be a threat to people, animal bacteria must first develop resistance to the types of antibiotics used in human medicine. Then these living bacteria would have to be transmitted to humans, or have their resistance factors transferred to bacterial species which can thrive in humans. Can this happen?
It's important to remember that the chances of humans acquiring any food-borne bacterial disease are extremely small if the products go through a thorough cooking or pasteurization process, and proper sanitation is practiced. Antibiotic-resistant bacteria would be killed by the same heating procedures that control other food borne pathogens.
Development of genetic resistance in bacteria is well documented. Genetic mutations which produce resistance occasionally occur, giving those bacteria a competitive advantage when exposed to antibiotics. Given enough time and exposure to an antibiotic, bacteria carrying these mutations are selected and these bacterial strains multiply. This has been observed in both human and veterinary medicine. And some of the antibiotics used in humans are used in livestock. But is there a link between antibiotic use in livestock and bacteria causing disease in humans?
At a recent conference, Dr. Fred Argulo of the Centre for Disease Control in Atlanta presented strong evidence supporting the view that resistant strains of Salmonella originating in livestock can cause disease in people, via transmission in food. At the same conference, Dr. Abigail Salyers of the University of Illinois showed that "resistance genes" are transferred among bacteria of the same species, and are likely passed to other bacterial species. She also indicated that the transfer of resistance genes from bacteria of animal origin (i.e. from food) to bacteria normally found in the human intestine is quite possible. These bacterial species, which are normally found in humans, do not usually cause disease. But if a person has been given antibiotics to treat or prevent infection (such as after surgery), this may suppress the other gut bacterial species and allow the resistant bacteria to multiply to the level where they can cause illness.
It's easy to understand the concerns about the use of antimicrobials in livestock. But considering only the risks while ignoring the benefits of their use in food production is not good science. As pointed out by Dr. Scott McEwen of the University of Guelph, science-based risk assessment should be used to evaluate the full benefits and costs of each antimicrobial drug. Factors which need to be considered include whether the compound (or others in the same class) are used in human medicine, and the level of risk ultimately presented to human health through use of that antibiotic. Other relevant factors are the impacts that restricting use would have on livestock health and productivity, the livelihood of farmers and the cost of the food produced.
Its time to take a critical look at how we use antibiotics in beef production. Finding economic ways to reduce the use of antibiotics which could affect humans without losing productivity on the farm would benefit both producers and society.
In the next issue: Strategies to reduce antibiotic use in beef production.
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Tom Hamilton is the Beef Production Systems Program Lead for the Ontario Ministry of Agriculture, Food and Rural Affairs. He also coordinates beef research at the New Liskeard Agricultural Research Station.
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Ontario Pork's food bank initiative takes a leap forward
by ROBERT IRWIN
Christmas is past for another year and, along with it, the traditional season for giving. But the Ontario pork industry is continuing to give.
Paul Mistele had no idea an idle quip he made during the pork price crash of November 1988 would spur the Ontario pork industry into the front lines in the battle against hunger in our province. At the time, he, his wife Carol and their two children were in the midst of market-driven losses which would eventually rob the hog, cash crop and broiler farm, which they have operated for 27 years, of about 53 percent of their equity.
"I said something like 'why don't we just send the hogs down to the food bank and we'll get more money for them.' It was a form of protest," recalls Mistele, president of Elgin County pork producers and an Ontario Federation of Agriculture provincial director.
As the idea took shape, Mistele realized that giving away hogs in exchange for a tax receipt might provide an opportunity to highlight the plight of cash-strapped producers, who were marketing hogs at a fraction of the cost of production. He also reasoned it would provide disheartened farmers with an opportunity to feel good through the act of giving during the Christmas season.
That Christmas, 190 producers offered more than 300 pigs. Nine came from the farm the Mistrele family has owned since 1853. Other industry players such as feed dealers, truckers and Ontario's two major packers contributed money or money's worth. "It brought them a great deal of publicity in the Toronto press," observes Paula Thiessen, special projects coordinator with the Ontario Association of Food Banks (OAFB).
A few other counties had active local programs, but "you don't get the same media attention with only localized programs," says Mistele. So he convinced a majority at Ontario Pork's annual meeting to get behind the idea. The pork board responded with a recently completed Christmas fund-raising drive.
This year, for about three weeks leading up to Christmas, instead of physically delivering hogs, participants were able to have the pork board deduct money from their settlement cheques. The board used the money to buy hogs which were then processed, courtesy of Quality Meats in Toronto.
Processed pork went to Toronto's Daily Bread Food Bank for distribution to its 89 registered members across Ontario. Thiessen says at last count there were about 215 known food banks across the province, "although some are quite small and operating out of somewhere like a church basement."
Ontario Pork has now built on Mistele's vision with a kit which helps county pork producer associations direct their efforts towards local food banks throughout the year. It includes a list of known food banks and a set of guidelines on how to operate a local program.
"In some cases, the abattoir will pick up the cost of processing, sometimes the local food bank will," notes Ontario Pork communications director Keith Robbins. Also included in the kit is a contact list of media outlets in hopes associations can help generate some good news for their industry.
Thiessen says Dairy Farmers of Ontario is the only other farm group consistently donating to OAFB. A program started by Vankleek Hill dairyman Alan Simpson in 1994 brings now brings in 600,000 litres per year.
"In general, food banks are not supported by government because it's seen as an admission of guilt," regarding policy on issues like taxation and housing, observes Thiessen. That leaves the door open for Ontario's pork and dairy farmers to move in and help, and they have seized the opportunity.
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