No silver bullet for phosphorus
In New Zealand’s soils, phosphorus does a great job at growing plants but unfortunately it does the same thing if it makes it into our water.
If we don’t look after them they may suffer flow on effects to their health, wellbeing and performance.
Cows too fat or too thin are at increased risk of metabolic disease and should be managed as higher risk animals.
Feeding stock is a large part of your job. Dry matter intake and quality feed are the most important aspect of stock management.
Often metabolic disease outbreaks can be addressed by increasing the amount of good quality feed which raises the intake of energy, calcium and magnesium. But taking a holistic approach via general good husbandry and good feed and supplementation is shown by research to be more important than ever before.
Intricate links between a cow’s homeostatic processes (the regulation of the cow’s internal environment) and metabolic processes are being continually uncovered.
Homeostasis arises from a natural resistance to change in optimal conditions and acts as an internal regulator to maintain equilibrium (wellbeing) despite changes in an animal’s environment, diet or level of activity.
For a cows’ metabolism to work at maximum efficiency it needs effective homeostatic control to keep things balanced. Without it, a failure of one metabolic process impacts on the efficiency of others and the cow becomes vulnerable to external threats and stresses.
Because of the influence of the homeostatic system, the concept of transition feeding prior to calving has evolved. Rather than focusing on the control of milk fever alone, the process requires the farmer to take an integrated nutritional approach. This will optimise:
• rumen function
• calcium and bone metabolism
• energy metabolism
• protein metabolism
• immune function.
Developing integrated strategies based on an understanding of the homoeostatic process will greatly benefit a cow’s wellbeing pre- and post-calving. In that brief, important transition period a careful manipulation of a cow’s diet can help her health and productivity.
Managing other factors will also affect a cow’s homeostatic system and consequent ability to absorb and retain nutrients at critical periods. The farmer must manage the stresses caused by:
• Lack of shelter in bad weather
• Deep pugged soils which make it hard for cows to get to feed, shelter and water
• Trucking (do this well before calving).
For example, while cows cannot store magnesium, and so need a daily adequate intake, the efficiency with which they absorb magnesium is strongly influenced by the concentration of potassium (K) in the diet. Getting optimal absorption requires a well functioning homeostatic system.
Calcium levels are also controlled by a very complex hormone system. Simply put, milk fever occurs when this hormone system doesn’t work properly or fast enough. It affects on average 5-10% of New Zealand dairy cows annually, with most cases occurring within 24-48 hours of calving (DairyNZ).
Like everything, the balance of the hormone system and calcium levels is controlled by the homeostatic system. So optimal conditions and diet are critical to give your cows the best start to the season.
• Julie Wagner is Ravensdown animal health product manager.
