Forage And Performance Of Dairy Cows

It is crucial to match quality foraged produced with the right type of animals. Early lactation dairy cows would require the highest quality forage in order to achieve their full potential.

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Milk Yield

• It is widely understood that cows of high genetic merit will be able to respond to high energy diets by increasing milk yields.

• There is a possibility that increasing milk yield will result in reduced milk solids %.

• Additional energy supplied may influence dry matter intake as well as modify the cows' performance response.

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Milk Fat

• Maintaining normal level of milk fat % shows effective rumen function, good cow's health and also provide economic advantage for producers where some of them are paid by milk fat %.

• Increasing digestible fibre intake will help to increase milk fat % as the fermentation of fibre in the rumen will produce acetic and butyric acid by the microbes.

  • Generally rule of thumb is to not feed less than 40% forage.​

  • Forage mixtures are encouraged as no single forage provides the ideal balance of nutrients.

• With that being said, there is a trade off between fibre and energy supply in early lactation.

  • It is important to focus on maximising energy intake in order to help reduce energy gap post-calving.​

  • It is difficult to achieve this without increasing the level of concentrates fed.

  • Feeding high quality forage can help to meet energy requirement while at the same time not compromising on the fibre supply to rumen.

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Milk Protein

• Two main sources of amino acids for milk protein production are:

  • Dietary protein​

  • Microbial protein

• Microbial protein provides a well balanced supply of amino acids to the animal at a low cost.

• In order to make use of the rumen degradable protein and turn it into microbial protein, the rumen microbes will require a balanced supply of fermentable energy.

• Hence, it is important to provide a balanced supply of energy as well as protein from a combination of high quality mixed forages and concentrates to maximise the dry matter intake, especially during early lactation.

• This will help provide enough energy and protein is available to the rumen microbes for optimal milk and milk protein production.

• General guidelines for using forage to increase milk protein production:

  • Feed mixed forages to help increase DMI​.

  • Maize silage may reduces butterfat when fed at high levels, however, it will increase milk protein.

  • High levels of legume silage may reduce milk protein and fat.

  • Fresh grass will help to increase milk protein %.

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Fertility

• Fertility seems to be a big problem in high producing animals.

• While feeding forage does not have a direct impact on fertility, feeding anything that can lead to an energy deficit such as feeding poor quality forage, will affect fertility negatively.

• Negative energy balance will delay the onset of oestrus which will result in decreased progesterone levels, causing problems with embryo implantation and survival.

• Excess protein nutrition also affects fertility negatively. Such cases can occur when:

  • there is excess rumen degradable protein in the diet.​

  • there is insufficient rumen fermentable energy

  • there is excess rumen bypass protein

• Excess ammonia can also affects fertility negatively.

  • Excess ammonia is detoxified in th liver by conversion to urea. This process is very demanding, which will further increase the cow's energy deficit.​

  • Hence, it is important to feed high quality forage along with other supplements to the high producing cows post-calving.