An important concept in dairy herd health is early diagnosis and treatment of sick cows. It may even be more important than the type of treatment administered. In lactating dairy cows, this concept cannot be overemphasized. A delay in treating a sick cow not only reduces her chances for a full recovery but results in milk production loss and may impair reproductive performance, especially if the disease occurs early postpartum.
Although we have made strides in postpartum cow management by implementing postpartum health monitoring strategies, quite often we fail to find a sick cow early in the disease course, which leads to a delay in treatment. Further, there are different opinions on health monitoring strategies, which parameters to use and how to interpret them. This [article] reviews parameters that can be used to monitor postpartum health and discusses clinical signs to look for in sick cows.
Monitoring postpartum health
The postpartum period of the dairy cow determines productive and reproductive responses during lactation. Therefore, it is a pivotal time in the production cycle of the cow. During this period, dairy cows are at risk of developing calving-related diseases such as hypocalcemia, metritis, ketosis and displacement of the abomasum. These are costly disorders with estimated economic losses ranging from 200 to 400 dollars per case per lactation.
Monitoring postpartum health allows the opportunity to identify sick cows early and provide supportive therapy. Furthermore, it can help prevent diseases. For example, a cow treated early for a uterine infection is less likely to develop secondary disorders such as displaced abomasum and ketosis. Another example would be a cow diagnosed with subclinical ketosis; if treated, a loss in milk production can be prevented.
Monitoring postpartum health involves the examination of all cows early postpartum (seven to 10 days in milk [DIM]) by trained farm personnel. Parameters that can be used to evaluate health status of cows include:
In the authors’ opinion, a common problem observed on many farms when monitoring postpartum health is that too much emphasis is given to one or two of these parameters. It is important to explain to farm personnel involved in health monitoring that the combination of these parameters must be considered when making a decision whether or not a cow is sick and requires treatment.
The premise for evaluating rectal temperature postpartum is that an elevated temperature indicates an abnormal health status. More specifically, in postpartum dairy cows, it most likely indicates a uterine infection or metritis. Monitoring rectal temperatures will result in a wide range of values from individual cows. The normal rectal temperature range for cattle can be from 101.5 to 103°F. Fever is diagnosed when the cow’s temperature is greater than 103°F. The variation in rectal temperature is influenced by factors such as health status, age, season of year and time of day.
However, cows with metritis may present with rectal temperatures within the normal range and may not necessarily develop fever. A Florida study that evaluated daily rectal temperature and attitude to monitor postpartum health found that over half of the cows diagnosed with metritis during the first week postpartum did not have a fever.
Cows with an abnormal parturition had rectal temperatures greater than 103.1°F related to metritis for significantly more days than cows that calved normally. Furthermore, Benzaquen et al. reported that cows with an abnormal calving had a higher incidence of metritis when compared to cows with a normal calving. From these studies, it can be concluded that cows with an abnormal calving (dystocia, retained placenta or twins) should be monitored carefully early postpartum.
Several studies have shown the successful use of antibiotics in cattle with elevated rectal temperatures related to metritis. Kristula and Smith reported a significant 1°F drop in temperature in cattle 24 hours after the initial treatment with antibiotics. Research done at Florida also showed similar findings where cows identified with toxic puerperal metritis and treated with antibiotics responded with a significant decrease in temperature the following day. From this data, it is safe to conclude dairy cows diagnosed with fevers due to metritis during the postpartum period respond positively to antimicrobial treatment.
The challenge when using monitoring programs is to decide when to treat cows. The Pennsylvania study cited earlier found that abnormal cows had their highest average temperatures on Days 3 through 6 and 66 percent of all cows treated were between Days 2 and 5 postpartum. Similar results were obtained by Benzaquen et al. These findings suggest the majority of cows develop fever within one week after calving. Therefore, monitoring programs using rectal temperature should be put in place for at least seven days after calving.
Some people are better than others at identifying sick cows based on their general attitude or appearance. It is imperative farm managers identify farm employees with this ability and train them properly. They should be taught to look at the eyes, ears, presence of uterine discharge and overall demeanor. Positioning and appearance of the eyes within the socket to assess level of dehydration or pain can be observed and scored. A scoring system such as 1 (minimal), 2 (mild), 3 (moderate) or 4 (severe) can be used.
A cow with a score of 1 usually will have bright eyes that are positioned normal within the eye socket. A score of 2 will have dull eyes that are slightly sunken (1 to 2 millimeters) within the eye socket. A score of 3 will have glazed eyes that are moderately sunken (2 to 4 millimeters), whereas a score of 4 will have dry eyes that are severely sunken (greater than 5 millimeters) within the eye socket.
Positioning of the cow’s ears is also a good indicator of a cow’s attitude. Sick cows usually have ears that droop down because of depression, pain or fever. Healthy cows, on the other hand, appear bright, alert and are curious about their environment. Upon being approached by someone, a healthy cow will often try to make contact with her nose and tongue.
In those farms that have locking stanchions, the attitude of the cow can be observed after feeding to evaluate appetite. A cow that is sick will not eat. Conversely, a healthy cow aggressively goes after her feed. In our clinical service we evaluate a cow’s appetite according to this scoring system;
1. cows that lock and eat
2. cows that lock, appear dull and do not eat
3. cows that do not lock to eat and appear dull or sick
We emphasize to employees that cows that fall in categories 2 or 3 should be monitored or examined carefully.
Daily milk production is monitored on many farms using computerized milking machines. Milk production values are related to the health of a cow. As mentioned earlier, a sick cow does not eat and consequently her milk production drops. Dairy cows with a normal postpartum period have a steady progressive day-to-day increase in milk production.
Determining the deviation value to identify these sick cows varies between farms. Some managers create a list of all cows that deviate from a value equal to or more than a preset value. In most dairies, a 10-pound drop in production is frequently used. Trained employees will use this deviation list to identify these cows and perform a thorough physical examination.
Dr. Tom Overton reported on a milk production monitoring program that evaluates milk production during the first 20 days postpartum. Overton reports that a goal for cows is a 10 percent daily milk increase during the first 14 days postpartum and for heifers an 8 percent daily increase. In addition, a cow should be producing close to 100 pounds of milk per day by 20 days postpartum and heifers 70 pounds per day. Cows and heifers that do not meet these criteria are identified and examined by trained farm personnel.
A common disorder during postpartum and commonly identified with a health monitoring program is metritis. Although there is much debate on the diagnosis of metritis, in our clinical service, cows that appear sick have a malodorous discharge from the uterus (regardless of her rectal temperature) and are considered to have metritis and require treatment. Therefore, we feel evaluation of uterine discharge is important for the correct diagnosis of metritis.
Particularly, as mentioned earlier, some cows affected with metritis do not develop fever. Discharges that are red-brown or contain mucus or pus that are not malodorous should be considered normal. A watery, foul-smelling discharge more often indicates a severe form of metritis that needs therapy as opposed to a mucoid discharge that more often indicates a recovering situation.
A common method used to evaluate uterine discharge is palpation of the uterus and visual inspection of the vulva for a malodorous, brownish-color discharge. However, this method of diagnosis is often inconsistent in the ability to produce and evaluate the discharge outside of the cow. Consequently, the use of vaginoscopy or the insertion of a gloved clean hand into the vagina and extending it to the cervix can be used to evaluate discharge.
Ketones in milk or urine
Ketone bodies in urine or milk can be used to diagnose ketosis in lactating dairy cattle. In our opinion, evaluation of ketosis in postpartum dairy cows is not used enough and is valuable in diagnosing sick cows. The cost of subclinical ketosis per cow is estimated to be $78. Ketosis has been associated with an increased risk to develop metritis, displaced abomasums and mastitis. A negative impact on milk production may also occur, and it has been reported that cows that produce a positive milk ketone test produce 1 to 1.4 kilograms less milk per day for the lactation.
Identification and treatment of cattle suffering from subclinical ketosis in the immediate postpartum period could reduce the negative side effects of ketosis. Identification of postpartum cows suffering from ketosis is accomplished either by analyzing urine or milk ketone levels using cowside tests. These cowside tests are based on the degree of color change occurring when ketone bodies in milk or urine contact a reagent. These tests are available as powders (commonly used in milk) and as urinalysis strips. Measuring urine ketone levels is most commonly performed because the technique to obtain a urine sample is uncomplicated, repeatable and cost-effective.
Putting it all together
Disorders such as metritis, displacement of the abomasum and ketosis can be evaluated by monitoring temperature, attitude, milk production and urine ketone levels early postpartum. A postpartum health monitoring program assures all cows are examined during the time they are most susceptible to disease, allowing the opportunity for early identification of cows that are sick.
Employing a postpartum health monitoring program, Benzaquen et al. reported that early treatment of cows with metritis resulted in pregnancy rates comparable to cows without metritis. This suggests identification of cows with metritis early and prompt treatment may ameliorate the effects of metritis on reproduction.
The following are key points to consider in the application of a postpartum health monitoring program:
•Identify key farm employees that have the interest to work with and treat sick cows. Train and work with them on a periodic basis. Have your veterinarian work with them side-by-side routinely. The basic premise in looking for sick cow is that the cow should be evaluated as a whole, considering attitude, rectal temperature, milk production and urine evaluation for ketone bodies.
•Create standard operating procedures (SOPs) for detecting sick cows, physical examination and treatment procedures for individual diseases. Review these practices frequently.
• Based on farm facilities and employee abilities, you and your veterinarian should decide which program works best for your herd.
•It is important health monitoring takes place for at least the first week postpartum. Days 3 to 7 appear to be the most critical.
–Evaluate attitude, rectal temperature and urine sample for presence of ketone bodies daily for 10 days postpartum.
–Examine cows for metritis, displaced abomasum and mastitis if they have fever (temperature greater than 103ºF) or appear sick, regardless of temperature.
–Cows that test positive on a urine ketone stick should be treated for ketosis.
–Consider an evaluation of uterine discharge on Days 3, 5 and 7 to make sure cows with metritis that do not have fever are not missed.
–Evaluation of changes in daily milk production for the first 20 days postpartum is a valuable tool that can be used effectively to evaluate health.
–Look for sick cows beyond the postpartum period. It is important to recognize that sick cow monitoring must be performed in all cows in lactation.
Farm personnel involved in moving, feeding, milking or breeding cows should be cognizant of the fact that they play a major role in the identification of sick cows. Consequently, they too should be trained in how to look for sick cows. Milkers should also be well trained in how to identify cows with mastitis. It is an important component of good milking procedures. PD
References omitted but are available upon request at firstname.lastname@example.org.
—From 2006 Florida & Georgia Dairy Road Show Proceedings