Delmarva Farmer Columnists


Which dewormer(s) work on your farm? (July 7, 2015)

Shepherd’s Notebook

By Susan Schoenian, Sheep and Goat Specialist, University of Maryland Extension

Worms have developed resistance to all of the dewormers and dewormer classes used to treat small ruminants.
Resistance varies by geographic region and individual farm and is the result of past deworming practices.
Worms do not develop resistance to specific drugs, but instead they develop resistance to the drugs’ mode of action (method of killing worms).
Dewormers in a dewormer class share a mode of action; thus, when resistance develops to one drug, there is cross-resistance to the other drugs in the same class, even if one drug is initially more potent — for example, albendazole versus fenbendazole.
From an industry-wide standpoint, resistance tends to be highest for the benzimidazoles or “white dewormers.”
This dewormer class includes fenbendazole (SafeGuard, Panacur), albendazole (Valbazen) and oxibendazole (Synathic).
Efficacy may be increased with increased exposure to the drug, but there is no guarantee that fasting and/or sequential dosing will be any more effective than a single dose.
Macrocylic lactones are another class of dewormers.
There are two sub-classes:  avermectins and milbemycins. 
Resistance tends to be highest among the avermectins.
The avermectins include ivermectin (Ivomec), eprinomectrin (Eprinex), and doramectin (Dectomax).
As with the benzimidazoles, efficacy may be increased with increased exposure to the drug.
Moxidectin (Cydectin) is the only milbemycin.
In the Mid-Atlantic region, resistance tends to be less for moxidectin as compared to avermectins and benzimidazoles; however, moxidectin resistance is developing rapidly due to its widespread use and chemical similarity to ivermectin.
The third class of dewormers are cell depolarizers, so-named for the way in which they kill worms. Levamisole (Prohibit) is the primary drug in this class.
It is the most potent and tends to be the most effective anthelmintic on most Mid-Atlantic small ruminant farms.
Less is known about morantel (Rumatel and Positive Goat Pellet) and strongid, the other members of this dewormer class.
No method of parasite control will be effective unless it is backed up by at least one effective dewormer.
Even “natural” or organic methods of parasite control must rely on effective drugs for treatment of clinically parasitized animals.
It is essential that small ruminant producers know which drugs are effective on their farms, as it may be different than the norms of the industry.
There are two ways to determine drug efficacy.
Before and after fecal egg counts can be compared to determine the efficacy of an anthelmintic treatment.
This is called the fecal egg count reduction test.
A fecal egg count reduction test needs to be done for each drug and with multiple animals.
It can be costly and/or time-consuming.
Many producers don’t have enough animals to get reliable results.
The other method to determine anthelmintic efficacy is the DrenchRite test or larval development assay.
This is an in vitro (lab) test that uses wells of larvae to determine drug efficacy. 
The test also determines the type of parasites that are present in the manure sample.
The only place (in the United States) that does the DrenchRite test is the University of Georgia.
At a cost of $450, the DrenchRite test may seem like an expensive option.
However, unlike the fecal egg count reduction test, it determines resistance to all drugs simultaneously from a single pooled sample.
Moreover, its cost can easily be justified when you consider the value of a few animals that may die because they are not dosed with an effective drug.
It would only take two 70-pound market goats to cover the cost of the test.
For more information about anthelmintic resistance, visit the web site of the American Consortium for Small Ruminant Parasite Control at or

Future deadlines and programs to think about (June 30, 2015)

Keeping the Farm

By H.L. Kellam, County Executive Director, Virginia Farm Service Agency

Letters have been sent by the National Office to Conservation Reserve Program participants with contracts expiring Sept. 30.
Conservation Reserve Program participants that have a contract under the general sign up that will be expiring on Sept. 30 may submit a request for a one year extension.
The deadline for requesting the one year extension is Aug. 28.
Don’t confuse this with the continuous sign up. Conservation Reserve Program participants with CRP contracts that are not eligible for the one year extension may offer the land expiring from Conservation Reserve Program on Sept. 30 for re-enrollment under continuous signup criteria, provided all eligibility requirements are met.
Early land preparation for seedbed for fall-seeded crops may be authorized beginning July 1.
Check with a local FSA office concerning other requirements.
Conservation Reserve Program and Conservation Reserve Enhancement Program participants who have contracts expiring on Sept. 30 may now offer to re-enroll ‘continuous’ contracts.
Producers with expiring continuous CRP and CREP contracts can re-enroll all or a portion of their land back into the program for another 10-15 year contract term. 
Re-enrolling an expiring CRP contract will allow participants to continue receiving annual rental payments, often at a higher rate than the original contract. 
Re-enrollment can also provide cost-share for enhancements and management activities. 
Re-enrolling participants may also be able to add acres to the contract.
The deadline to submit an offer for continuous CRP/CREP re-enrollment is Aug. 1, 2015. 
The re-enrolled contract must be approved prior to Sept. 30 and become effective on Oct. 1.
Visit your local FSA office soon and allow the FSA staff to help you determine your options!
An additional 800,000 acres of highly environmentally sensitive land may be enrolled in Conservation Reserve Program under certain wetland and wildlife initiatives that provide multiple benefits on the same land.
The USDA will accept new offers to participate in CRP under a general signup to be held Dec. 1, through Feb. 26, 2016.
Farmers and/or land owners interested in removing sensitive land from agricultural production and planting grasses or trees to reduce soil erosion, improve water quality and restore wildlife habitat are encouraged to enroll.
Farmers may visit their FSA county office for additional information.
For more information on CRP and other FSA programs, visit 
Eligible producers may now formally enroll in the Agriculture Risk Coverage and Price Loss Coverage programs for 2014 and 2015.
The enrollment period began June 17 and will end Sept. 30.
Remember acreage reporting deadlines in your state.
Contact a local FSA office for the applicable reporting deadlines.
Finally, the FSA County Committee nomination period for local FSA County Committees began on June 15 with nomination forms being postmarked or received by the County FSA office by close of business on Aug. 3.
To find out which Local Administrative Area or Areas are up for election contact a local FSA office.