KY Dairy Notes (Spring '23)
Monthly Tip: First-Calf Heifers Behave Differently than Mature Cows
First-calf heifers should be housed separately from the mature cows, if at all possible. Heifers take smaller bites of feed and spend more time eating than mature cows. Studies have shown feeding times increased by 11% and milk production increased by 9% when heifers are housed separately from mature cows.
Separation of first-calf heifers from mature cows is even more critical when freestalls are overcrowded and/or feedbunk space is limited, i.e. with 6-row barns. Heifers are more submissive than mature cows and do not compete as well for stall and bunk space when challenged . Resting time, a critical need for cows, is reduced more for heifers than cows when overcrowded. Cows prioritize resting time over feeding times.
Successful Dairy Managers—What Does it Take to Be One?
Over my 35-year professional career, I have been blessed to visit and work closely with many successful dairy managers. As I reflect on these experiences, I quickly realize that many common threads exist between these managers. These commonalities extend past how they manage their dairy cows on a daily basis and reflect more on how they make decisions and approach their business. Their personal skill sets speak to the success of their herds and the ability to be both profitable and successful.
Decreases in Milk Production Seen 1 to 2 Days after Heat Stress Event
The dog days of summer definitely come with increased environmental temperatures and, often times, high humidity, resulting in heat stress conditions for dairy cows, as well as those who care for them. Heat stress results in an increased body temperature, which can negatively impact milk production, reproductive performance and health of cows. These effects can be seen in not only the milking herd, but also in dry cows, heifers, and baby calves. To maintain a normal body temperature, cattle must dissipate heat generated from digesting their feed along with the additional heat load from their environment with increasing temperatures. Shade, air movement with fans and through natural ventilation, and wetting of the hair coat with sprinklers/soakers help decrease this heat load and help mitigate the negative impacts caused by heat stress to dairy cattle. By learning more about how dairy cows respond to heat stress, one can better manage one’s dairy herd and minimize the negative impacts resulting from heat stress
Maintenance of Fans Impact Electric Bills
Ventilation systems which circulate air within barns can account for a large proportion of an electric bill. Some estimate they may account for 20 to 25% of the total electricity usage, especially when barns are mechanically ventilated. Even with increased costs for electricity, the use of circulation fans for increased air speed are a necessary expense to reduce heat stress and to prevent the associated decreases in milk production, reproductive performance, and performance of future generations. When temperatures are greater than 65ºF, fans are needed to move air to help cool cows. The goal during the warm time of the year is to exchange the air in these facilities 40 to 60 times per hour with the air moving at the rate of 300 to 400 feet/min (3.5 to 5 mph) at the level of the cow. Poor or inadequate fan maintenance can decrease the overall airflow by fans as well as the efficiency of these motors by as much as 40%; thus, increasing electric bills unnecessarily. As little as 1/8 inch of dust on the fan blades can decrease the efficiency of the motor of the fan. Maintenance on fans should be completed not once, but 3 to 4 times per year, to improve/maintain the efficiency of the fan motors and air speeds within the facility. These steps include:
- Clean dust from the blades, motor windings, sensors and thermostats.
- Lubricate the fan according to the manufacturer’s recommendations.
- Check the belts for wear and stretch. Belts should ride on top of the pulley. Replace belts as needed.
- Check the electrical cords and wiring for breaks or disintegration of wiring covering.
- Check that the thermostat is operating properly- i.e. comes on at the proper temperature (65ºF)
- Check the angle of each fan such that the air movement of the fan “blows’ to the ground level below the next fan.
Early Embryonic Pregnancy Losses Vary by Stage of Gestation
The recommendation is to pregnancy test cows around 30 days after being bred to identify cows that are open so that open cows can be rebred in a timely manner. Cows that are pregnant by 130 days in milk have a lower chance of becoming overconditioned in later lactation and have been shown to rebreed in a more timely manner in their subsequent lactation.
Pre-Milking Cow Prep Influences Somatic Cell Count
When it comes to maintaining a low herd somatic cell count, continuously practicing sound milking procedures are part of an effectively implemented, on-farm milk quality plan. Dairy managers understand the importance of following proven milking procedures, but the component that often gets overlooked is translating the importance of continuously and consistently completing these practices to those actually milking the cows. When these procedures are routinely reviewed or re-reviewed with employees or other family members, an increased understanding can lead to a higher rate of correctly implementing these practices, avoiding the development of bad habits, and the ability to maintain a low somatic cell count. Even herds using robots to milk their cows need to review whether the robot is correctly completing each of these components associated with pre-milking prep.
Observation is the Key to Being a “Cow Whisperer”
Observing the behavior and, more importantly, changes in behavior of an animal or group of animals is one of the components necessary when working with animals. All of us quickly recognize that a dog with its hair standing up along its back and a non-wagging tail is not in a “friendly mood” and one best back away from the situation. When it comes to dairy cattle, observational skills are important in the day-to-day management of cattle, especially when we wish to move them in the direction intended. Also, understanding how dairy cows react to novel situations, and more importantly, what constitutes a novel situation to them is important as we manage their movement to and from the daily activities associated with milking and general management practices.
Dry Cow Therapy Revisited
Prevention of mastitis and successful treatment of clinical cases when needed are the hallmarks of a cost effective and successfully implemented mastitis program. The use of correctly-applied pre-dip, stripping of foremilk to check for clinical mastitis prior to attaching the milking machine, post-dipping the lower 3/4rds of the teat with a germicide at the conclusion of milking, routinely serviced and properly operating milking equipment, and maintaining a relatively “clean” resting environment are vital parts of any mastitis prevention plan. In addition, the use of dry cow therapy plays a key role in these on-farm mastitis prevention protocols.