By Tara L.Felix
While there are many stressors animals are exposed to during this transition – weaning, transport, environment, and so on – one of the biggest stressors is related to changes in diet. Diet transition generally occurs for 21 to 28 days after new cattle arrive at a feedlot. The easier we make the transition for young calves from pasture to grain, the better they will do throughout the feedout period. Thus, the goal should always be to make this transition as easy as possible for them. There are a few fundamental principles in order to ensure success.
I will begin by saying that sickness during the transition period is nearly inevitable. Thus, it is critical to work with your veterinarian during feedlot receiving and transition to help overcome and prevent sickness. Having an established veterinary-client-patient-relationship (VCPR) will ensure that you have access to treatments those cattle may need. Hospital pens should be clean and comfortable and cattle there should be treated with as little disruption as possible for best results. However, it is best to be proactive rather than reactive when it comes to animal health. Work closely with your veterinarian to establish an operating herd health protocol.
Upon arrival to the feedyard or feedlot, cattle are often stressed, dehydrated, and weakened from hauling. The combination of exposure and dehydration decreases the calf’s ability to fight pathogens and predisposes them to diseases. Bearing this in mind, management upon arrival is crucial to a successful transition. Cattle arriving at the feedlot should be granted rest off the truck. Many professionals recommend a minimum of 24 h of rest prior to processing (discussed below) cattle. During this rest period, cattle should be provided with clean water and long stem hay. Consider providing a tank, perhaps with running water, as cattle enter the pen so that they can see and hear the water. These initial hours are key to the success of the transition.
Once cattle have arrived and are rested, they will need processed – vaccinated, implanted (if being done), and, preferably, weighed. During processing, cattle are often separated into homogeneous groups – similar weight, sex and ideally the same origin. Consider regrouping animals only once because every time cattle are resorted or regrouped, their dominance hierarchy is disrupted. Cattle that are regrouped require about 20 days to reestablish their hierarchy through competitive behavior which disrupts intake and reduces feed efficiency, thereby impacting the bottom-line economics.
Even without regroups, the intake pattern of cattle during the first week in the feedlot is usually erratic and highly variable among animals and throughout the first days, as we can see in the graph below. According to research, normal feed intake will not resume until 21 days after receiving. Thus, focusing on nutrition during these early days will play a very important role in the success of the feedlot.
One of the challenges of the erratic intake behavior described above is that it may lead to ruminal acidosis. Ruminal acidosis occurs when there is a more rapid production of acids than the rumen wall can absorb. The acid production drops ruminal pH and can cause ruminitis, or inflammation of the rumen mucosa. Many times, feedlot operators do not realize acidosis has occurred; however, digestive disorders are the second most abundant cause of morbidity in confined cattle, behind only respiratory conditions. Any morbidity, or sickness, can reduce cattle growth throughout the entire feeding period. Thus, the goal during transition should always be to alleviate digestive upsets and maintain digestive function.
Because it takes time for the rumen to adjust to dietary changes, it is necessary to adapt cattle to a high-concentrate diet by gradually increasing grain concentration in the diet and decreasing fiber content. Many nutritionists recommend a 14 to 21-day transition to grain, depending on whether or not cattle have ever been exposed to grain. Newly weaned calves from pasture-based systems with little exposure to grain prior to feedlot entry may require a slower transition than yearlings that have been backgrounded with access to some grain, for instance. Slower dietary transitions as cattle move from pasture to grain diets can help reduce the number of digestive upsets encountered in the feedlot.
In addition to a slow transition to grain, controlling or managing intake can help alleviate digestive upsets. Corn contains roughly twice as much energy as hay. By limiting intake while grain is being introduced, the number of changes the calf is exposed to each day is limited. While managing cattle intakes, it is important to remember that nutrition is more about consumption than concentration. While diets are often discussed on a percent crude protein (CP) basis, cattle require a certain amount of protein every day. Thus, when intakes are restricted, a greater protein concentration must be fed in the diet in order to meet the needs of the growing cattle.
After cattle are fully transitioned to grain, managers can begin to gradually increase the amount of feed offered. Cattle feeders are constantly challenged when transitioning calves to the feedlot. While these tips can help, working closely with a nutritionist, to ensure receiving diets and nutritional management meet the requirements of newly weaned calves, and veterinarians, to make sure the health of the herd is also a priority is encouraged to ensure a successful transition to the feedlot.Source : psu.edu