In dairy cattle the transition period is characterized by a number of metabolic changes and management practices that can have an impact in the health and productivity of the cows. Therefore, strategies and monitoring programs that can minimize the negative effects of these events in the herd should be implemented.
Generally, the transition period starts three weeks prior to the due date and extends three weeks after calving. Animals are moved to a new pen in preparation for the new lactation where they have to adjust to a new ration, social group, and facilities. After calving, some animals will present some form of metabolic disorder or infection. Transition cows will experience insulin resistance, low feed intake, negative energy balance, lipolysis, weight loss, and reduced immune function during early lactation.
Bacterial contamination in the uterus, in addition to a number of hormonal changes, can result in retained placenta and metritis. All these events will have effects on the future performance of the cows and their productivity.
Sometimes health issues will go unnoticed as animals will not show clinical symptoms. However, subclinical cases will affect productivity and in the long run, they might even have a significant impact in other factors such as reproduction performance and culling rate. For instance, studies indicate that cows diagnosed with subclinical ketosis in the first two weeks of lactation were 20% less likely to get pregnant in the first insemination (Walsh et al., 2007).
Considering all the factors that affect the development of the cows, producers should have a good health monitoring program that aims to prevent health problems at the herd level and identify cows at high risk for diseases at the individual level.
Numerous screening programs have been proposed with different benefits and advantages. However, producers should adjust to resources available in their farms and create an effective program tailored to their conditions and circumstances. Lack of technology or time should not be an excuse to have a poor health monitoring program.
Accurate records of all the health events are a good starting point. They will offer a retrospective picture and determine if disease incidence rates are exceeding normal standards.
Incidence of clinical diseases such as retained placenta, milk fever, dystocia, metritis, ketosis, and displaced abomasum should be available and be reliable. It is important to be clear and consistent with the records. This will help to give a better diagnostic tool, plan an effective treatment, and evaluate the success of the current management. Furthermore, records should be able to provide incidence of a condition and not be confused by treatment rate. For instance, if there is a case of retained placenta that was not treated, this one should be recorded. On the other hand, if there is a case of metritis and it is treated for 5 days, it should be recorded as only 1 occurrence and not as 5 treatment events.
Although clinical cases are important and need to be addressed, they are only showing a fragment of the real situation on a farm. Subclinical ketosis, for instance, can affect up to 40% of the cows in early lactation (Duffield et al., 1998), and yet be unnoticed in many cases. That’s why other monitoring practices are needed in addition to good records.
Dry matter intake
Adequate consumption of feed during the prepartum and postpartum periods can have a significant effect in the cows. Measuring the intake is an effective tool to prevent health issues. Animals should be encouraged to eat as much as possible during the post-partum period to avoid negative energy balance, but intake should be controlled during the far-off period to avoid over conditioned cows. Research has shown that cows that were overfed during the far-off period had higher concentrations in blood of BHB (?-hydroxybutyrate) and NEFA (non-esterified fatty acids) that are correlated with higher incidence of ketosis (Dann et al., 2006).
After parturition, milk yield should steadily increase. Keeping track of this information can be used to monitor health status. Generally, if cows are experiencing any kind of health issues, milk yield will be affected. When evaluating milk production, it is important to remember that other factors (animal handling, feed, weather, etc.), besides health, can influence its outcome.
Currently, a number of automatic milking systems that can report individual milk production are available. Additionally, other animal monitoring systems have been demonstrated to be an excellent complement of milking systems to identify sick cows early. The goal is to daily monitor the milk production, at least for the first 2 weeks of lactation.
Scoring body condition will give an estimate of how much body fat the cows are accumulating. This information is also a reliable source to determine nutrition and metabolic status in the herd. Studies have shown that body condition score is associated with health and reproductive performance of the cows. Over conditioned cows or cows that lose 1 point or more of body condition are more likely to have health problems. However, body condition score will not be able to predict diseases or reproductive performance by itself. Studies suggest that transition cows should have a body condition score of 3 in order to avoid health problems (Roche et al., 2009).
Nowadays, the market offers technology that can measure body fat based on digital images taken from the cows when exiting milking parlor. In conjunction with other strategies, this tool can be another excellent option to prevent and find sick cows.
In addition to the monitoring strategies presented above, other health parameters can be measured to complement the health evaluation of the cows. A daily measurement of the rectal temperature as well as sporadic rectal palpations will help to determine the status of the reproductive organs. Similarly, weekly samples of urine, blood, or milk can be collected to measure BHB concentrations and determine the energy status. The market offers on-farm tests that are relatively inexpensive and easy to use.
The decision of treating a cow must take into account all the previous explained factors. Moreover, the routine check-ups should be done by well trained and experienced personnel under the supervision of a veterinarian.
To conclude, transition cows are vulnerable and their behavior and performance needs to be monitored closely. Early identification and prevention of health issues must be a priority. There are many easy tools and strategies available for producers that can be easily adjusted and implemented in the farm’s management practices.
Dann, H. M., N. B. Litherland, J. P. Underwood, M. Bionaz, A. D’Angelo, J. W. McFadden, and J. K. Drackley. 2006. Diets during far-off and close-up dry periods affect periparturient metabolism and lactation in multiparous cows. J. Dairy Sci. 89:3563–3577.
- Duffield, T. F., D. Sandals, K. E. Leslie, K. Lissemore, B. W. McBride, J. H. Lumsden, P. Dick, and R. Bagg. 1998. Efficacy of monesin for the prevention of subclinical ketosis in lactating dairy cows. J. Dairy Sci. 81:2866-2873.
- Roche, J. R., N. C. Friggens, J. K. Kay, M. W. Fisher, K. J. Stafford, D. P. and Berry. 2009. Invited review: Body condition score and its association with dairy cow productivity, health and welfare. J. Dairy Sci. 92:5769-5801.
- Walsh, R. B., J. S. Walton, D. F. Kelton, S. J. LeBlanc, K. E. Leslie, T. F. and Duffield. 2007. The effect of subclinical ketosis in early lactation on reproductive performance of postpartum dairy cows. J. Dairy Sci. 90:2788–2796.