Why Supplement?

  1. Nutritional Requirements of Livestock
  2. Wet Season Supplementation
  3. Dry Season Supplementation
  4. Weaning

Nutritional Requirements of Livestock

Supplementary feeding aims to correct nutrient imbalances present in the available pasture, by increasing intake and/or improving utilisation of available paddock feed. With any livestock enterprise, the entire farm management strategy revolves around great seasonal variations in pasture production which, depending on location and time of year, can be low in both protein and digestibility.

The aim of most beef cattle and sheep producers is to generate the maximum return from available grass. In order to achieve this, supplementation is a necessary key management strategy in Northern Australia.

Making The Most Out Of Grass

Provided there is an adequate quantity of grass available, pasture quality determines live-weight gains and productivity. Pasture quality is a function of the digestibility and protein levels of the pasture. Digestibility is measured by that proportion of the diet that is used by the animal and not passed out as faeces.

Digestibility Measurements

The higher the digestibility, the faster the feed passes through the animal, the more pasture the animal can eat and as a result, greater live weight gains are achieved. Pasture quality and availability vary throughout the year which is reflected as a variation in live weight gains. As protein and digestibility fall, so does feed intake and consequently stock may fail to gain weight or start to lose weight.

The Link between Digestibility, Protein And Energy

As pasture feed reaches maturity, the available digestible energy and protein levels fall, resulting in slower ruminal digestion with a consequent reduction in feed intake. This leads to reduced livestock performance and productivity.

Digestibility of pasture is largely influenced by the stage of pasture growth. As pasture matures, digestibility declines and energy and crude protein content falls.

Below: Digestibility declines as pasture matures
Regardless of the type of pasture, when digestibility falls below 50% and crude protein levels fall below 5-7%, most stock will lose weight and milk production will decline dramatically. Fertility may also be affected.
What are The Nutritional Requirements of Cattle and Sheep?

To maintain normal body functions, cattle and sheep require certain minimal levels of:

  • Protein
  • Energy
  • Minerals
  • Trace elements
  • Vitamins

However for productivity gains (e.g. growing out, finishing or breeding) the requirements of the above are even greater, particularly for protein and energy.

Microbes in the rumen break down the fibrous component of feed to produce energy. These ruminal microbes require a constant source of nitrogen for their survival and growth. Nitrogen is obtained from digestible crude protein found in grasses and other feeds, and from supplements of non-protein sources such as urea.

Adequate protein and energy is the key to a healthy rumen.

If the barrel on the left represents the nutritional well being of an animal and our aim is to fill the barrel to maximise the animal’s productivity, then it becomes obvious that we need to shore up the nutrient that is lowest. In this case it is protein. Once protein and energy have been supplied then phosphorus may limit production.

The "principal of limiting nutrients" says that there is no point supplementing the animal with phosphorus for example when protein and energy are the limiting factors. There will be no response until the limiting nutrients are satisfied.

The Primary Limiting Nutrient is Protein

Most of the digestion of forage occurs in the rumen by bacteria. In fact the rumen is very efficient at digesting roughage and inefficient at digesting grain.

The aim of feeding cattle and sheep is to ensure the rumen is working at maximum efficiency. As pastures mature this efficiency, along with feed intake declines and therefore supplementation is required to maintain productivity.

The choice of supplements is critical in stimulating maximum efficiency in the rumen and at the same time allowing some of the supplement to bypass the rumen. When pastures decline in protein and digestibility, large increases in feed intake and production response can be achieved by strategic supplementation.

Cattle and sheep absorb protein through the intestines. This can come from two sources:

  • A regular supply of microbial protein produced in the rumen passing to the intestines for absorption. As the microbial population in the rumen declines, this source of protein also declines.
  • Bypass protein. This is a particular type of feed protein which is not broken down to any large extent by the ruminal microbes, but which flows through the rumen to be directly available for absorption in the intestines. Protected or bypass proteins help maximise production and productivity in ruminants.

As crude protein levels fall in pasture, microbial protein becomes the main source of protein for the animal. However, as feed protein levels drop, the rumen microbes are also placed under nutritional stress due to lack of incoming nitrogen. This will result in slower digestion and a reduction in feed intake. Under these conditions, a supply of non-protein nitrogen (NPN) such as urea will maintain the animal’s microbial population, ensuring that sufficient microbial protein is produced for body maintenance.

Energy Requirements

Cattle require energy for:

  • Maintenance of body functions
  • Growth and production

The amount required will vary with the productive status of the animal. Without irrigation, supplementary feeding is generally essential during the winter dry season in northern Australia.

Pasture management in northern Australia is important in maintaining high levels of pasture digestibility, including stocking rates and pasture types, to meet the energy requirements of high producing cattle and sheep. However, without irrigation, it is impossible to maintain high levels of digestible feed.

Trace Elements

Deficiencies of trace elements, particularly selenium, cobalt and copper will impact on the productivity of cattle and sheep. Supplementation can generally help remedy such deficiencies in a cost-effective manner.

Wet Season Supplementation

Phosphorus - An Important Mineral

Cattle and sheep have a continuous need for phosphorus for growth, reproduction and lactation. However, the phosphorus content in pasture can vary greatly during the season, with low levels regularly found in dry, mature pasture.

As seen below, the vast majority of northern Australia is phosphorus deficient.

The following livestock may require phosphorous (P) supplementation:

  • Growing cattle, lactating or late pregnant cows
  • Cattle grazing the following soils:
  • -- P Deficient soils ( 5mg/kg or less)- all stock should fed P supplements
    -- Marginal P soils (6-8mg/kg)- feed P to young breeders and test old breeders for P
    -- Adequate P Soils (Exceeds 8mg/kg) – economic benefits of feeding P are marginal
Signs of phosphorus deficiency include:
  • Reduced feed intake
  • Depraved appetite (pica or bone chewing?)
  • Poor growth rates in young cattle and sheep
  • Reduced fertility
  • Reduced milk production
  • Ragged, rough coats with poor colouring
  • Abnormal bone development (e.g. peg leg)
When should P be fed?
  • Livestock respond best to P supplementation when levels of protein and energy are adequate in the diet. Wet Season is P supplementation is most effective.
  • Feeding P to livestock grazing on deficient country can:
  • -- Increase weights in young growing cattle by 40-60 kg per year -- Increase lactating breeder conception rates by 15-20%
    Before feeding P, it is important to understand:
    • Your country type and soil P levels
    • The available quality and cost v benefit of P supplements
    • Measure up what is practical and identify a supplement that will ensure balanced intakes throughout the wet season

    See our LNT Phosrite Product

    Dry Season Supplementation

    In a normal dry season we are looking at providing breeders with a low input, minimum cost per head supplement that minimizes weight loss by providing the limiting nutrients- protein and energy.

    So, why Dry Season Supplement?

    Breeders in the north are limited by lack of protein during the dry season.

    • Low protein limits the intake of forage which is the low cost energy source driving northern beef breeding operations.
    • Breeder weight at the start of the next wet season will govern speed of re-breed and overall calving rate next time around. Dry season supplementation with urea can give a live weight benefit of 5 – 10 kg per month. The value of 10 kg of additional live weight is an improvement in conception rate of about 5%. These benefits are economically compelling.
    • Dry Season Supplement ingredients

      Urea is the main supplement ingredient used during the dry season. In technical terms, urea is a concentrated form of non-protein nitrogen for making protein and works well provided there is dry feed available.

      A dense form of protein suits northern herds where limited labour and large transport distances are the norm. Some phosphorus is used in mixes when urea is supplemented on low phosphorus soils.

      Salt is also required in the north and is added as a carrier and attractant. Sulphur is required when urea is supplemented and protein meals and trace minerals are added as required.

      See our LNT Uramol Product


      Calf weaning is an often underestimated management tool to maximise the output from your breeding herd.

      The process of weaning dramatically reduces a breeder cow’s nutrient requirements. This has flow on benefits to the herd because the combination of body reserves and nutrition has important effects on milk production, weaning weight and conception rates.

      Dry season feeding has a crucial role in retaining cow body condition; but have you considered which is a more important strategy for retaining body condition?

      Research 1 suggests that weaning earlier improves live weight potential by 0.35 kg/day compared to weaning late. It also has a greater impact than dry season supplementation, which improves live weight potential by only 0.11 kg/day. The good news is that the effect of earlier weaning and dry season supplementation are additive.

      It is almost impossible to wean every calf early and early weaning is not a “free lunch”. The lower the weaning weight, the more intensive the management and feeding options required to ensure the calf continues to grow.

      Choosing the right type of weaner supplement will vary widely between individual properties. It will be dependent upon the feeding objectives, infrastructure and labour.

      1 Dixon RM, Playford C, Coates D (2011) Nutrition of beef breeder cows in the dry tropics. 1. Effect of nitrogen supplementation and weaning on breeder performance. Animal Production Science 51, 515-528.

      Can weaners compensate for a slow nutritional start?

      Weaners (e.g. less than six months of age and less than 150 kg live weight) will not compensate at all, or if they do not nearly to the same extent as older cattle. When good nutrition is available following nutritional restriction these young cattle are likely to grow at much the same rate or only slightly better than if they had not been restricted. These animals are likely never to achieve their full growth potential.

      See our LNT Boost Product