Nutrition
Nutrition Articles
Feeding the Beef Herd in a Drought Year
This year the drought continues to reduce yield of both grain and forages. This means drought influenced feeding programs will be used on farms this coming feeding season. Reviewing the principles involved gets us prepared to avoid nutritional shortfalls and ready to manage for the best outcome. Nutritional shortfalls can cause many unwelcome effects in beef cattle. Of particular interest is the immune system and its optimum functioning. In all living things, “These diverse functions of immunity are bioenergetically expensive, requiring precise control of cellular metabolic pathways. Since immune cells lack significant stores of nutrients, these effector responses can only be sustained if immune cells can dramatically increase the uptake of glucose, amino acids, and fatty acids from their microenvironment. ”1 This means that these fuels for the immune system need to be available when these challenges come. Energy is consumed by the cow in the form of forages and grain which are chewed, hydrated in the rumen, attacked by rumen organisms as well as being fermented to produce all the elements needed to supply nutrients for growth and defense of the animal’s body. Supplementing a mineral mix can also help the immune system to respond.
One of the major tasks as managers of a beef herd is to ensure sufficient feed is supplied both in amounts and quality to meet all health and growth challenges without over supplying nutrients. Over supplying of protein for an example has a metabolic cost to the animal of removing it from the body. Nutritionists are frequently emphasizing this point not only because the animal has to divert energy from growth or maintenance, but it has a financial impact in that nutrients are being fed which do not contribute positively to the animal. In addition many research papers report that over or under feeding causes an enlargement of the liver and gut system which is attempting to compensate for nutritional distress. “Animal performance is determined by the combined effects of both prior and current nutrition.”2 Substantial periods of over or under feeding will have an effect on the ultimate carcass yield of a steer or heifer. In addition, feeding excessively high protein for developing replacement females can slow the growth rate and cause fat deposition in the developing udder setting up a potential problem of mastitis, lack of milk, post calving cleaning. These issues occur incrementally over time but a plan for proper forage utilization and ration formulation can avoid all of them. Dr. Holland Dougherty of the University of New England, Australia, studied lambs which had a period of feed restriction then were returned to a balanced ration to see what happened to carcass yield. “As dietary energy density increased, the rumen became proportionally smaller while the liver became proportionally larger. Liver size increased with increasing RUP, and lambs fed 30 and 60 g/d were fatter than other lambs. However, lambs fed 90 g/d RUP had less fat than other lambs, as the increased energy requirements of a larger liver and of disposing of excess nitrogen appeared to outweigh any nutritional benefits. Understanding how prior nutrition affects current performance, as well as how tissues vary in their response to the same diet, is key to improving our understanding of animal performance and response to change.”2
Feeding crop residues has proven a dependable and cost effective way to spare higher quality feed for transition months and lactation. Dairy cattle have demonstrated higher intakes of less desirable forages when the forage is chopped. Highline® has a Feed Chopper™ option for the Bale Pro® which reduces particle size to the theoretically ideal cut length for increased consumption. Many of the users of the chopper comment on extended feeding days and less waste from sorting. Using this principle and combining chopped crop residues with higher quality forages or grain, a best cost ration can be formulated and fed to maintain the beef cow or develop the heifer without any negative effects while optimizing forage utilization and daily feed costs. The temptation when high quality feed is available in quantity is to “treat” the cows and heifers. During some periods of feeding this constitutes excessive levels of protein and can cause the animal to slow progress towards maturity and calving success. It also raises daily feeding costs unnecessarily.
There are no secrets to successful feeding programs and here are producer proven steps;
• List inventory of forages with their nutrient test results and store forages to prevent weathering
• Assign a cost per pound for using this forage in rations including their processing/mixing cost
• Formulate for each category of animal a life cycle set of rations including a 10% waste factor
• Change rations slowly to allow rumen bacteria a chance to adapt
• Evaluate the impact of the feeding program as it is delivered and adjust if necessary
• Supplement when pastures grow thin and intake is challenged
• Focus on the bottom 25% of the herd to assure they are keeping up on intake of feed
This approach ensures the best possible chance that all animals are consuming enough feed for their body to meet the demand for readily available nutrients in a disease challenge, or for growth. Highline has a line of feeding equipment to assist you in delivering a quality mix to all classes of animals.
1. Metabolic Regulation of Immune Responses, Kirthana Ganeshan, Cardiovascular Research Institute, University of California San Francisco, 94158-9001, USA and, Ajay Chawla, Departments of Physiology and Medicine, University of California San Francisco, 94158-9001, USA, Annu Rev Immunol. 2014 ; 32: 609–634. doi:10.1146/annurev-immunol-032713-120236.
2. Effects of dietary energy density and supplemental rumen undegradable protein on intake, viscera, and carcass composition of lambs recovering from nutritional restriction.
Holland C Dougherty 1 2, Mark Evered 2, James W Oltjen 3, Roger S Hegarty 1, Stephen A Neutze 4, V Hutton Oddy 2 J Anim Sci 2022
Jul 1;100(7):skac158 doi: 10.1093/jas/skac158