Thinking Small About Cow Comfort
By Tom Van Dyke, DVM, Merial Veterinary Services
We are lucky to have people in the dairy industry who think big about cow comfort. They have paved the way for major improvements, and they have the ability to enhance our farm production, economics1, animal stewardship and consumer perception.2 But even with these benefits, there are times when it pays to think small about cow comfort. Thinking small means directing attention to the tiny but significant threat to dairy cattle comfort caused by lice and mange mites.
Cattle lice are among the most important arthropod pests affecting dairy cattle because all lice – the blood-sucking or skin-chewing varieties – can cause extreme annoyance to the host animals. The animals’ tendency to rub leads to hair loss, reduced feed conversion efficiency, and unthriftiness.3 Milk production in heavily infested cattle can be reduced as much as 25 percent.4
Knowledge of the louse life cycle is important to ensure proper insecticidal management of a lice infestation. Lice, in contrast to other livestock pests, are permanent parasites that spend their entire lives on the host animal. Their spread within the herd depends on cow-to-cow contact. Female lice attach their eggs to cattle hairs with a glue-like substance to make sure they stay put. The eggs hatch within approximately 10 to 14 days, and a few short weeks later, the lice are fully developed.3 Their shells, which are strong and thick, help them survive insecticides.4
Lice may be small (4 And though winter’s reduced light intensity may contribute to lice amounts, nutrition, weather patterns, and animals’ overall immune system responses are also significant.5
Smaller still are mange mites, almost invisible to the naked eye. Mange mites, like lice, are permanent external parasites that spend their entire life on the animal and, depending on direct contact, with infested carriers. There are two economically important mites that affect dairy cattle – Chorioptes spp. and Sarcoptes spp. You have no doubt seen dairy cows with scabbiness and hair loss around the tail head, feet, and legs. That is the work of the Chorioptes mite. These mites live on the surface of the cow’s skin, causing inflammation and irritation, and then feeding on lymph and dead cells. Populations of mites usually increase with cooler weather, and high levels in dairy herds can reduce milk production.3 The results of a Chorioptic mange trial showed an increased milk yield of 3.3 lbs. per cow, per day, after whole herd treatment.6
Skin lesions caused by Sarcoptes are so severe that infestation with this mite is considered a reportable and quarantinable disease. These lesions are the result of an animal’s immune reaction as the mites burrow deeply into the skin. It only takes a few mites to cause intense itching, hair loss and scabbing. This mange may first appear around the tail, udder, legs and feet, but can eventually cover the cow’s entire body.3 In a Sarcoptic mange study, the results showed increased milk production of nearly 4.4 lbs. per cow, per day, after whole herd treatment.7
Because they are so small and inconspicuous, lice and mange mites may be out of sight and out of mind until cattle start showing characteristic signs of infestation, such as itching, hair loss and scabbing. By this time, populations of these parasites are well above economic injury levels in the herd, and successful treatment cannot only be more difficult, but also more urgent.3 Prevention and treatment protocols should be in place to avoid reaching this point.
First, try not to bring new animals into the herd that may be infected. Closely inspect new purchases and pass on cattle with suspicious skin lesions. If new cattle are brought in, fully treat and quarantine before mixing them with the rest of the herd. Closely monitor the herd for early signs of lice or mange. Choose timely, whole-herd treatments to prevent buildup of external parasite numbers. Even at low levels, lice and intestinal nematodes can combine to decrease weight gain by more than 8 percent.5
The ideal treatment product should:
- be broad-spectrum that include lice and mange8
- cover multiple parasite species8
- be labeled for lactating cattle8
- persist long enough to kill nymphs hatching from eggs present at the time of first treatment.8
Controlling external parasites fits into the big picture of cow comfort, and cow comfort pays big in many ways. But this time, think small.
About Merial
Merial is a world-leading, innovation-driven animal health company, providing a comprehensive range of products to enhance the health and well-being of a wide range of animals. Merial employs 6,100 people and operates in more than 150 countries worldwide with more than €2 billion of sales in 2014.
Merial is a Sanofi company.
For more information, please see www.merial.com.
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©2015 Merial, Inc., Duluth, GA. All rights reserved. RUMILGN1586 (09/15)
1Grant R. Economic Benefits of Improved Cow Comfort. NOVUS, William H. Miner Agricultural Research Institute. Rev 2013. Available at: http://www.dairychallenge.org/ne_event.php. Accessed September 9, 2015.
2Walker J, Golab GC. What?! Animal Welfare? & Why Now?. Available at: www.agweb.com/assets/1/6/Why_Welfare_Why_Now_JW_GCG_DBA_Meeting.pdf. Accessed September 9, 2015.
3Rutz D, Geden CJ. Pest Management Recommendation for Dairy Cattle.
A Cornell and Penn State Cooperative Extension Publication. 2010;1-12.
4Youngman R. Now Is The Winter Of Our Discontent: Well, At Least Where Cattle And Lice Are Concerned. Virginia Cooperative Extension Livestock Update. 2001.
5Townsend L. Lice on Beef and Dairy Cattle. University of Kentucky Cooperative Extension Service. 2000. Bulletin no. ENTFACT512.
6Schönberg J, Ilchmann G, Schein E. Eradication of Chorioptic Mange in a Grazing Dairy Herd With Eprinex Pour-On. Berl. Münch. Tieräztle. Wschr. 2000;113:144-148.
7Watson CL, Forbes AB. An Outbreak of Sarcoptic Mange in Dairy Cows. UK Vet Livestock. 2000:5(4):48-50.
8Currin J. Lice in Dairy Cattle. Virginia Cooperative Extension Dairy Pipeline. 2008;29(1).
