While cases in some years are more prevalent than others, I expect to continue to see an increase in milk fever (hypocalcaemia) cases in beef cattle in Alabama. I have already talked with a few producers who are already experiencing this nutritional disorder.
While most producers focus their attention on grass tetney during the spring, we should not ignore milk fever as another concern in beef cattle during this time of the year. What is milk fever, how do you prevent it, what are common signs and can you treat the disorder are all common questions that need to be addressed.
While milk fever is most common in dairy cattle, beef cattle can also be affected. Milk fever is a condition caused by low blood calcium and is characterized by general muscular weakness, circulatory collapse, terminal coma and death. The condition usually occurs in cows at calving or within three to four days post-calving in high producing cows. Cold, wet conditions only elevate the incidence of milk fever. The frequency also increases as the cow gets older and if the cows are being fed heavy amounts of grain before calving.
Signs of the disease are common and can be often confused with grass tetney. The cows will be excited, have stiff legs and a staggery gait. The cow will become drowsy and will be unable to rise. An affected animal will turn her head into her flank and will have a dry muzzle. Untreated, the cow will go into lateral recumbancy, become bloated and often die.
Treatment for this disorder must be prompt. A calcium injection, given either slowly intravenously or subcutaneously, should correct the problem, but not the cause. Be aware rapid intravenous injection may lead to cardiac arrest, so a combination of intravenous and subcutaneous injections is useful. Also, realize under dosing is often the cause for a relapse. Cattle will respond rapidly and will get back on their feet rather quickly when treated in this manner.
The best way not to have a case of milk fever is to understand the causes and prevent the problem from occurring. As mentioned earlier, milk fever is caused by low blood calcium. Calcium-rich milk is needed for the development of bone in the young calf along with other functions like muscle contraction and transmission of nerve signals.
Since milk production increases the cow’s calcium demand, her body must be prepared to supply the extra calcium. This calcium must come from her diet and from a process pulling some of the calcium from her bones. Milk fever will develop from her inability to pull the calcium from her bones.
Milk fever can occur in one of the following situations: One cause is a poorly balanced mineral program leading to a mineral imbalance in the cowherd. Phosphorous is a common mineral that will bind to calcium making it unavailable to the cow for utilization. Therefore, a diet with a higher percentage of phosphorous over calcium could lead to milk fever because the cow cannot use the calcium in its diet.
How do you correct this situation? You must first run nutrient analysis on your forage, feed ingredients and soils. Then you should adjust your mineral program based on this information to prevent disorders.
Pay very close attention to your forage and soil information if you use chicken litter as fertilizer. Over 90 percent of the reported cases have occurred in fields fertilized with litter or cattle were consuming hay fertilized with chicken litter. Chicken litter has a high percentage of both calcium and phosphorous which could lead to an imbalance.
A second cause is from either depressed or excess calcium levels in the diet. I do not believe you will have a problem with depressed calcium levels unless it’s from being tied up by phosphorous. Most commercial minerals will provide a high percentage of calcium in their product for cow-utilization; therefore, having low calcium levels in their diet is very rare.
Excess calcium in their diet can be a major problem and is usually the number one cause for milk fever in beef cattle. Excess dietary calcium can cause the cow to use dietary calcium less efficiently; therefore, when the demands for calcium increases at calving, the cow’s body is not prepared to start the process of supplying the additional calcium from her body. This will lead to low blood calcium levels and milk fever.
The cause of excess calcium is usually found in a nutrition program utilizing several products with high levels of calcium. The use of chicken litter as a fertilizer source seems to be the common thread in excess calcium levels being found in cattle. This along with a complete mineral that is over 16 percent calcium and or in combination with cattle being fed a product like soyhulls, also high in calcium, can lead to excess calcium in their diet. If you have cattle exposed to two of the three situations listed above, you should be very aware of the possibility of milk fever occurring in cows as they prepare to calf.
Prevention is always the easiest to incorporate into your program. Be aware of the calcium and phosphorous levels of your total feeding program, including soil composition. Regulate the amount and the number of times you utilize chicken litter as a fertilizer source.
Provide cattle with a complete mineral and vitamin supplement in the proper ratios to meet all of the needs of the animal. Know the mineral composition of any feed ingredients provided to your cattle. While milk fever is not a disorder beef producers are familiar with, it is increasing in frequency and can cost a lot of money in cattle loss.
This is also the time of the year for you to determine your fly control options for the coming months. Flies cost cattle producers billions of dollars each year in lost weight-gain and in the spread of disease. You have several options to consider when combating these parasites. Rabon® and insect growth regulators (IGR) (S-methoprene) are two feed additives available. Both products work on the next generation of flies and will not give you immediate visual control if you already have an infestation of flies.
These two products are available in feeds, minerals and supplement tubs, and are very effective in controlling flies at a low cost per-head per-day. When using either of these two products it is very important you get them out at least 21 days prior to the beginning of fly season. I would recommend you go ahead and get these products out at this time for effective early control.
You can also consider fly tags as another viable option in fly control. Next generation fly tags are available providing a new chemical to help combat flies. There are several different options available in fly tags and I would suggest working with your local Quality Co-op manager in selecting the most effective tag for your situation. We also have sprays and backrubs available that can be very effective in the knock-down of flies if you already have a problem needing immediate attention. These products are all effective in providing short-term control of flies.
A final product that will also provide some fly control is the use of pour-on wormers. While these products are not designed for long-term fly control, they will give a two to three week fly control when properly administered as part of a parasite control program. Some producers have found it cost effective to use generic wormer products as a way to control flies by pouring the product on cows several times during the fly season.
I would not recommend this as a fly control program. This practice will lead to resistance in internal parasite control and could lead to serious issues in the years-to-come in association with internal parasite control. I encourage you to consider any of these products as an effective way to control flies.
Jimmy Hughes is AFC’s animal nutritionist.