by Katie Navarra
Parasites are the most important limiting factor in small ruminant flocks because they are the most difficult factor to control, especially as parasites have become resistant to our most common anti worming chemicals. “These invisible killers have proven a formidable foe in the biological battle to raise healthy and happy animals for food and we here at the extension agency are actively promoting best practices to ensure that our local animals are safe and we are not perpetuating the cycle of resistance,” said Jason Detzel, livestock educator, Cornell Cooperative Extension of Ulster County (CCEUC).
In a series of two workshops, he offered management techniques to help farmers lower fecal egg sample counts, treatment while avoiding resistance and promoting healthy flocks.
“Blanket treating all of the animals in a flock leads to pest resistance,” he explained. “An integrated pest management approach is the most viable option.”
The first step is a fecal egg count. This is a simple procedure that is performed to get an approximation of the parasite load in your sheep or goat flock. Traditionally, a fresh fecal sample for each animal is taken to the veterinarian or sent to a lab and studied under a microscope to determine the amount of parasites present. Flock owners in the Ulster County, New York area can request access to the CCEUC microscope and analyze their own samples for a small fee.
“This makes it much more economical for individuals to test their flock on a monthly basis from May through September, the timeline we suggest monitoring small ruminants the closest for parasites,” he said.
Fecal egg counts are one part of the equation. Observation is another. Animals with a healthy hair coat and good body condition are likely not infested with parasites. “If they have runny manure or are in poor condition, it may be an indication of a parasite infestation,” he said.
It’s also important to estimate the level of anemia in sheep and goats associated with the barber pole worm by checking the tissue around the eyes for blood loss using the FAMACHA© test.
“The FAMACHA card was developed in South Africa and is a tool that matches the color of the eye mucous membranes of small ruminants with a laminated color category that corresponds to different levels of anemia,” he said.
This season, he anticipates that barber pole worm populations will be higher than in recent years. The life cycle of the barber pole worm, and most parasites for that matter, are closely tied to the availability of moisture to grow and metamorphosis into their more advanced life stages. Last year, many parts of New York experienced a significant drought which naturally controlled the parasite population in pastures and in livestock.
Liver fluke, also known as deer worm, can be problematic in small ruminant flocks because you can’t tell an animal is infested until it is sick. “Keep the animals out of wet areas where snails and slugs are likely to be because those insects are intermediaries for liver fluke,” he said.
Once you know what the parasite load is in your flock and can identify the animals that are most susceptible to worms to treat those animals and/or cull them from the herd. “Within a flock, 20 percent of the animals are shedding 80 percent of the parasites into the pastures,” he said. “Culling those animals from the flock can significantly reduce parasite loads.”
Pasture management is another component to managing parasite levels in a small ruminant flock. “Parasites are species exclusive so the best scenario is rotating pastures with different livestock like cattle or horses,” he said.
Today alternating livestock species isn’t as practical as it once was, but developing a “grazer’s eye” can help you determine when to turn a flock out and remove them from a specific pasture to lessen parasite loads. “You have to watch the pastures closely for how quickly the grass is growing and recovering and take the time of year into account,” he said.
Becoming a skilled pasture manager takes training. CCEUC offers a two-day course scheduled for Aug. 25-26, 2017 to teach the skills needed to develop a pasture rotation that meets the nutritional needs of your flock and the forage. Information can be found at http://ulster.cce.cornell.edu.
Detzel also posts a weekly blog featuring livestock management tips. Read more at https://jasondetzelccelivestock.wordpress.com.