Mud in your pastures or corrals can depress feed intake, reduce feed efficiency, lead to acidosis, increase the incidence of clinical mastitis and cause injuries.

An article on the effects of mud on feedlot cattle could have just as easily been applied to dairy cows. Here are some of the [reported] findings:

• 4 to 8 inches of mud can decrease feed intake by 4 to 8 percent.
• 4 to 8 inches of mud can slow gains by 14 percent.
• 4 to 8 inches of mud can reduce feed efficiency by 13 percent.
• “Belly-deep mud” can reduce feed intake by 30 percent.
• “Belly-deep mud” can reduce feed efficiency by up to 25 percent.

They found that effects of mud are more significant when the cattle are wet and cold. As the mud gets deeper and creates a suction (like when your boot comes off and you step in it with your sock foot), cattle tend to give up on moving around to the feed bunks. Often the worst place for mud is at the edges on concrete aprons or alleyways. Due to the runoff from the concrete, the mud may be much deeper in these locations than in the rest of the corral.

With the depression in feed intake, they reported that there is an increased risk of acidosis. As the cattle become less willing to fight through the mud to get to the feed bunks, they tend to slug-feed when they do make the effort to eat. Some days they may just lay up and not eat at all. One of the results of acidosis is laminitis, whether subclinical or clinical, leading to lameness.

The slippery mud surfaces also led to increased risk of injury. Cows were seen to have trouble keeping their footing as they came down off the bedding mounds. They may also injure themselves when coming off the concrete into the muddy corrals. Slips and falls may be more common on the concrete pads due to accumulation of mud carried onto the pads by the cows. Needless to say, there is more foot rot and hairy foot warts during wet conditions.

Besides the difficulties mud poses for the cattle, it can also be a hazard for the pen workers. Excessively muddy corrals make it more difficult for the pen workers to detect sick cattle. Sick cows in muddy pens tend to just sit and present fewer signs of disease. The pen workers must decide if it is more beneficial for the cattle to be treated when sick and use the extra energy to move them to the hospital pens or to let them stay in the pen without treatment and the stress of moving through the mud.

So what does all the feedlot information mean to the dairy? Certainly, decreased feed intake due to deep mud can be related directly to lower milk production. Like feedlot cattle, dairy cattle become reluctant to wade through deep mud to get to the feed bunks. In the bull pens, the bulls are more likely to lay than to detect heat and take a chance of falling when breeding a hot cow. Both cows and bulls utilize a lot of energy just to get to the bunks that would otherwise be turned into milk or used to breed cows. The subtle result may be more lameness due to acidosis, foot rot and hairy foot warts.

Certainly, injuries are more common due to slips and falls with wet conditions. Mastitis becomes more common due to environmental pathogens, and the hospital pen swells to twice or three times normal. The bulk tank somatic tank shoots up. Milkers get grouchy after fighting the mud in the corrals and spending the extra time to prepare the cows for milking.

Some of the problems related to muddy conditions are preventable by proper grading of corrals and the cow mounds. Adding additional bedding under the shades in the corrals can also make the cow more comfortable. Amendments can be used to firm up the junction areas between the concrete pads and dirt corrals. Dairymen should do what they can to decrease the effects of mud on cow health and production.

Dr. Paul Blackmer outlines the following critical areas of concern under wet-weather conditions to prevent mastitis.

1. Corral surface management
Keep cows clean, dry and comfortable by scraping and piling manure, fill low spots, pave high- traffic areas, keep drainage channels open and provide permanent dirt mounds.

2. Hair removal
Help keep udders clean and dry by flame singeing or clipping and docking tail hair.

3. Wash pen utilization
Maintain fast, efficient cleaning of udders by checking nozzles frequently, maintaining adequate pressure and ensuring adequate wash time.

4. Pre-milking udder prep
Maintain clean, dry udders and efficient milk let-down by predipping, using individual towels, foremilking to detect mastitis and wearing gloves during milking.

5. Control machine-on time
Utilize high milk flow rate and decreased machine-on time to ensure healthy teat skin and teat ends.

6. Postmilking dipping
Prevent spread of mastitis by contagious bacteria and maintain teat skin and teat end condition by monitoring coverage, new infection rate and skin condition.

7. Postmilking udder environment
Allow dip to stay on teats by avoiding excess use of drop hoses (especially hosing floors in the parlor exit area) and providing feed in bunks after feeding.

8. Immunity for gram-negative pathogens
Immunize before periods of stress using J5 type vaccine following manufacturer’s recommendations for dosage and boosters.

9. Monitoring
Monitor new clinical cases by culture, monitor repeat or chronic cases to determine the organisms causing the mastitis, monthly bulk tank cultures and watch numbers of mastitis cows in hospital pen.

Although some of these suggestions may seem costly, together they provide a comprehensive plan to limit mastitis outbreaks. Of the critical areas listed, the one that may be the most helpful to producers in a mastitis control program is number nine (monitoring). Total prevention of mastitis is difficult in most herds. Consequently, producers should develop a realistic plan to control mastitis outbreaks. To establish an effective mastitis control program, two major objectives must be set:

1. New infections must be prevented.
2. Duration of infections must be reduced.

To obtain these objectives, producers need to monitor the mastitis prevalence in their herd. Clinical cases should be noted by date, cow number, quarter, treatment, treatment response and withdrawal time. This can be done either on a fancy spreadsheet or just a binder kept in the barn. It is important to know which type of bacteria is causing the clinical mastitis cases, especially repeat or low-response cases. Culture samples should be taken on a case-by-case basis, and a list of chronic cows should be kept to determine possible cull cows.

Non-clinical mastitis should also be monitored as part of the control program. This is not as straightforward as monitoring sick cows, but it can be accomplished by using creamery and DHIA data or results of personally submitted tests. By monitoring bulk tank SCC, DHIA SCC for lactation groups and individual cows and culturing high SCC cows, producers can create a fairly accurate picture of their non-clinical mastitis rate.

Culturing the bulk tank for bacteria and mycoplasma monthly or bi-monthly will also aid in determining the non-clinical mastitis rate in the herd. Dry cow treatment effectiveness can be monitored by culturing fresh cows a few days after calving, and environmental mastitis prevalence can be determined by culturing first-calf heifers. PD

—From University of Arkansa Dairy Digest, Vol. 15, No. 2

John H. Kirk
Extension Veterinarian
University of California – Davis