Infection Control Management
Infectious diseases are problems that occur in animals when they are invaded by another biological organism. This contrasts with metabolic diseases that are the result of a metabolic disfunction, like ketosis and milk fever. Invasive organisms can be as small as a tiny virus to a macroscopic tape worm. Things like tapeworms and round worms are referred to as parasitism and will be discussed at another time.
Infectious disease occurs when exposure to a pathogenic organism exceeds the host immunity to that organism. Lat month we talked about the ability of vaccines to boost immunity. Things to remember about vaccines are numerous. Timing of vaccines to when the host can best respond to them is important. Timely boosters are essential to the effectiveness of the vaccine. Not all vaccines are created equal. You often will give up efficacy for convenience. So, it is important to work with someone who understands immunology and the characteristics of the vaccine options to develop an optimal vaccine protocol for your herd. There are products other than vaccines that can boost immunity such as Amplimune, Immrestor, and Refined Functional Carbohydrates as found in Nutritec and Celmanax. Start to use these products as defined by peer reviewed, published research. Once they prove their worth, expand to off label indications while following label dose instructions.
Today I want to focus on exposure management. Let’s start with transition cow management and birth of the calf. Feed intake is critical to optimal transition cow performance. Most people have 5 stanchion holes in 10 feet of feed bunk in the close-up pen. This is fine for Jerseys, if you do not overcrowd the pen. However, Holsteins do best at 80% stocking or 100% if you have 4 stanchion holes per 10 feet. This was clearly demonstrated by a friend who owned a dairy in Artesia, NM. He had 5 holes in 10’ and gradually reduced his stocking density from 140% to 70%. He found peak milk in the subsequent lactation maxed out when he was at 80% stocking density, or 2.5’ of bunk space per cow. Subsequent research demonstrated that infectious problems in the fresh cows, such as metritis and mastitis were reduced when stocking density was around 80% as well. Take care of the close-up cows and they will take care of you.
Many chronic infectious diseases start with the calves. Johnes is shed in the colostrum and manure of fresh cows. Crypto is shed in the manure of fresh cows and persists indefinitely in the environment. Salmonella and rotavirus are shed in the manure and milk, especially during times of stress. E. coli is everywhere all the time. Fortunately, exposure of the calf to these organisms can be controlled with comprehensive management and sanitation programs. Keep close-up cows eating as much as possible for 3 weeks before calving. During the summer and with cows bred to easy calving bulls, this may require moving heifers and cows to the close-up pen 4 weeks before the expected due date. Heat stress and breeding for calving ease tend to result in short gestation length. Move cows from the close-up pen to the calving area in stage 2 of parturition, when a part of the calf is showing out the back. Time in the calving pen should be measured in minutes to hours rather than hours to days. Ideally catch the calf as it leaves the cows, realistically do not leave the calf in the calving environment for more than an hour. If accomplished, individual calving pens are not needed and are more difficult to clean. Clean the calving pen daily and bed with clean sand. Straw on top of the sand would be great and may be necessary during cold weather. But it is more difficult to clean out of the pen and an added cost. Disinfection of the base of the calving pens should be customized to the most prevalent organism infecting the calves and is not usually necessary. All of this will control mastitis and metritis in the cows as well.
Exposure control and immunity boosting in the close-up and calving pen will deliver optimal production by the cows and a lifetime of benefits for the calves. Additional control measures to reduce exposure are pathogen specific and usually involve test and cull or isolate. You can spend a lot on pathogen specific immune boosting products or time and effort on exposure control. Usually a plan to address immunity and exposure is most effective.