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Newsletter of Penn Dutch Cow Care May 2004

Hi Folks,

Pasture season is now well under way and so I thought I would talk about problems that can occur with cows out on pasture. What? Cows on pasture can get problems? Yes: bloat, rumen acidosis and hoof problems.

First, let’s talk about pasture bloat. This is a kind of bloat that is entirely preventable yet there will still be some farmers that experience this in their herd. Pasture bloat occurs when animals are put into really lush legume or legume/grass mix paddocks for a few days in a row, without any hay being offered prior to being sent out to pasture. For some reason, the legumes (clovers and alfalfa) will slowly but surely create millions of tiny bubbles that accumulate over a few days time. At some point, they build up to a point where the rumen entrance and exit constricts and none of the bubbles can escape. This is when the cow rapidly bloats (as seen with a big bulge on their left side), begins to violently kick at her belly because of the extreme pain, then can no longer stand, drops down and dies.

With good management, this is a preventable condition, although a good farmer may still lose one animal to this kind of bloat in a season. It is when there is a whole bunch of cows that show this problem, a few times in a season, that there is a real nutritional problem that needs to be fixed. Usually bloat pasture occurs on the cooler ends of the pasture season, but it can occur truly at any time. I’ve heard farmers say that cows simply won’t eat hay when there is pasture available. If this is the case, put molasses on the hay. Use long stem hay, not the “candy” hay from out west (western hay has excellent relative feed value, but not much effective fiber). Baleage and haylage will not substitute for actual dry hay because they are already partially digested due to the fermentation process.

Treatment for pasture bloat is rather simple, if you are in time. Poloxalene (Bloat Guard®) works very quickly, often within 2-3 minutes. Mineral oil can also be used, one pint and repeat in 10 minutes. It is a bit slower acting, but will do the job. Also, Tide® liquid detergent will do the job, but I don’t know how much is needed (probably about 4-8 ounces). The poloxalene and mineral oil are OK for organic, the Tide® probably is not. If the cow is down already, it is too late. In this kind of bloat, passing a stomach tube will not relieve the tight rumen. Stabbing the cow where the bulge is biggest, on the left side can be of value, but then she will definitely need antibiotics (her left is your left if standing behind her).

Another condition, also due to lack of effective fiber, is rumen acidosis. This is can be seen even when low levels of grain are being fed if no hay is being fed (and can still happen if baleage and haylage are offered). Rumen acidosis is more commonly seen anytime of year on farms that feed high amounts of corn silage, high moisture corn and grain supplements fed by TMR. Although both causes of rumen acidosis cause pathologic changes to occur in the rumen because of the drop in pH, I believe that the acidosis caused by lack of hay during the pasture season is probably not as damaging to the cows system as the kind of acidosis caused by the high silage and grain diets. Why? Because pasture is not foreign to a cow’s rumen while the high moisture and grain when combined with large amounts of corn silage is. Sure, our cows (Holsteins and Jerseys) these days have been bred to produce high amounts of milk when fed certain diets (with grain assumed to provide much of their energy needs), but actual intake of fresh grasses is still highly compatible with the bovine species under any condition. Therefore, even though the biochemical burning of the rumen wall that takes place when acidosis occurs will happen to both pastured cows and confined cows, I believe that the cows’ ability to bounce back from an acidosis episode is greater when out on pasture. By not making as much milk while on pasture, they are not as metabolically stressed, and this may be one of the main reasons.

Typical signs of rumen acidosis would be decreased or no cud chewing, loose or diarrhea manure, becoming skinny, decreased milk and possibly grinding their teeth. The treatment is rather simple: long stem dry hay, bicarb (baking soda) free choice or force fed, and rumen probiotics. If a cow is truly acidotic, she will eagerly eat dry hay to the exclusion of other feeds.

Unfortunately, the consequences of rumen acidosis are many, but one obvious one is on the hooves. With the permeability of the rumen walls increased due to the biochemical burning of the acidosis, pathogenic toxins can escape into the animal’s circulation. Unfortunately, the circulation down to the hoof area is very complex and suffice it to say that interference with normal circulation can cause an upset in the integrity of the hoof-hairline junction. With this weakness created, it may be more likely that the bacteria that is presumed to cause strawberry heel has a better chance to take hold in that area (especially when cows stand around in mud and muck) and create the characteristic lesion. In addition, the general growth of the hoof is changed and anytime that happens, other problems can take advantage of the weakened hoof structure. It is interesting to see in some herds that the hooves of all the cows have a line on them (parallel to the hoof-hairline junction) – this is diagnostic of rumen acidosis having occurred.

Other problems that can occur to hooves that will decrease the enjoyment of cows out on pasture include abscesses and foot rot. Foot rot is contagious (just as strawberry heel is). Installing a box with a dry hydrated lime that the cows must walk through is a nice antiseptic and preventative for contagious problems. It is less messy than the copper sulfate baths and will not quickly max out your soil’s copper levels. However, if you are organic, you cannot dump the hydrated lime on your fields when done with it. Perhaps adding in some dry copper sulfate powder to the hydrated lime would be better yet. Abscesses occur when stones puncture hooves that are soft from standing in manure or wet areas. Abscesses also occur when the ground is hard and dry when there is no “give” and the hoof gets punctured because of full weight applied to them when walking.

By making sure your cows get dry hay and that your cow lanes have an even walking surface, your cows will enjoy the pastures much more this season.

Notice:

Benuel M. Stoltzfus, 648 Cambridge Road (just west of Churchtown Rd. and Cambridge Rd. junction) will be hosting a pasture walk on Tuesday May 11th from 10am-2pm. A light lunch will be provided. Come and visit with your fellow graziers and learn from each other. Ben’s phone is 768-3437, can leave a message.

 

For Bovinity Health, information on functional alternatives to antibiotics see:
www.bovinityhealth.com

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