Getting cattle supplementation right
11 February 2016
By Désirée Jackson, Désirée Jackson Livestock Management and an MLA Nutrition EDGE program presenter
One of the most frustrating challenges for producers is figuring out which supplement is going to do the best job for their cattle
And one of the biggest costs in running a northern cattle enterprise is the feed bill. Therefore, every time a supplementation program is implemented, it has to be a winner. Inappropriate supplements or insufficient intake of nutrients costs a lot of money in the feed and worse, in a loss of productivity.
Here are the factors to be considered in selecting a supplement or formulating a customised supplement.
1. What animals are being fed and why?
Establish the objective of the feeding program. Have a clear goal in mind and determine whether it is achievable by examining how the diet quality in the paddock matches the target animal nutrient requirements.
Do you need to:
- hold condition
- production feed for early turn-off
- bring heifers to a joining weight, or
- maintain breeders and heifers at optimum condition scores at calving to ensure they resume cycling soon after calving?
Focus on one paddock or group of animals at a time. Determine what their protein, energy and phosphorus requirements are as a starting point. These are the “big three” nutrients that are usually the first to become deficient.
Different classes of animals have vastly different requirements, depending on their weight, stage of growth or stage of productivity – one supplement is usually not appropriate for all animals. Couple this with land system and diet quality differences between paddocks and it complicates things further.
2. What is the pasture situation? How much pasture is available? How long will it last and is a supplement being fed?
The increased grazing pressure needs to be accounted for in the forage budget at the start of the dry season.
Firstly, we always need to make sure there is sufficient roughage available to the animal. Cattle are ruminants; roughage provides carbohydrates and some nitrogen which the rumen microbes convert to energy and microbial protein that the animal can use for their own maintenance or production. Without enough roughage in the diet, the rumen microbial population diminishes rapidly, which is extremely limiting to livestock production.
Disasters with supplementary feeding, such as urea poisoning, molasses toxicity, grain poisoning or ammonia poisoning, can happen when available pasture is low and cattle are struggling to consume enough roughage from the paddock, or if the diet quality is poor and cattle are starving for nutrients, particularly energy, causing them to gorge on available supplements.
3. Are there any endemic deficiencies in the paddock?
The most common of these across northern Australia is phosphorus, but other minerals such as sulphur, salt, copper, cobalt and selenium, for example, have been identified in some regions. These nutrients must be supplied or the efficiency with which the cattle can utilise other nutrients is greatly diminished. However, it is important to ensure that trace elements are not oversupplemented as a deficiency can soon turn into a toxicity. The effectiveness of supplementing minerals is greatly diminished if protein and energy are deficient in the diet.
4. What is the most limiting nutrient in the diet?
This is the nutrient that must be supplied first. For example, early in the dry season, protein is often the nutrient that becomes deficient first, followed by energy. In the wet season on P-deficient country, phosphorus is the most limiting nutrient.
The class of cattle that is fed will also influence which nutrient is most limiting, because of variable requirements so this must also be considered.
5. What is the balance of nutrients?
There is often too much focus on balancing nutrients, or minerals in a supplement. The supplement provided must always be balanced with what the animals are receiving from the pasture. Care must be taken that nutrients in the supplement are balanced with the pasture nutrients to ensure that the target nutrients that are supplemented are fully absorbed. For example, where cattle are running on P-deficient country, if too much calcium is provided in the supplement, this can interfere with phosphorus absorption because on tropical grass pastures, calcium levels tend to be much higher than phosphorus levels. This can not only cause wasted dollars spent on supplementation but significant losses in productivity.
Another example where supplementation can be ineffective is when a urea-based lick is being supplemented, but energy is much more deficient in the diet relative to protein. This is why ongoing monitoring of diet quality is so important – because as the diet quality changes, the most limiting nutrient in the diet will also change. This means that the supplement also must change over time to be the most effective.
6. Is the intake correct?
This is probably the most difficult aspect of supplementation to monitor – due to multiple watering points and cattle being nomadic in the paddock or calves consuming lick put out for breeders, etc. However, it is critical that not only should the supplement contain adequate levels of the desired nutrients, but also that cattle are consuming enough. Just because a supplement contains phosphorus for example, does not mean that the cattle are consuming enough phosphorus. The lick may be too low in phosphorus or the consumption rate is too low. The lick may need to be modified to maybe increase the phosphorus level.
Sometimes lick intakes are too low but not because cattle don’t require specific nutrients – they may just be too unpalatable. Where lick intakes are excessively high, this can be due either to lick palatability or a deficiency that hasn’t been addressed. This commonly occurs with urea-based licks where consumption may become excessive because the diet has become energy deficient because animal nutrient requirements have increased (eg. breeders start calving) or pasture has become low in quality and cattle start compensating by increasing lick consumption. Ingredients such as salt and sulphate of ammonia are used to control lick intake. Care should be taken when using sulphate of ammonia that it does not cause over consumption of sulphur or a nutritionally unsound low nitrogen:sulphur ratio in the diet.
More information: Désirée Jackson E: desireejackson@bigpond.com
