An effective feeding system allows maximum intake of a nutritionally balanced ration. As the level of production of dairy cows continues to improve the coverage of the nutritional needs of cows is a growing challenge for modern dairy producers. Aside from milk production, it is also important to provide the nutrients needed for reproductive purposes - conception and pregnancy. Proper nutrition is also essential to ensure that the cows can defend against infections such as mastitis and metabolic problems such as milk fever and ketosis.
One of the most effective ways to feed the cows, to cover their production potential, is to house, to feed and manage the animals in groups.
Over the past years, considerable research has been conducted on dry cows and especially in cows that are in the transition period (i.e. three weeks before calving and three weeks postpartum). This separation allows the use of higher levels of energy and protein in the ration, which are necessary, as the feed intake begins to decrease as they reach calving. Moreover, this division allows the intended use of feed additives such as amino acids, b-carotene, niacin, protected choline, propylene glycol and anionic salts.
There are many criteria used for grouping of lactating cows. These include:
1. Level of milk production
3. Days in milk
4. Reproductive status
Although the choice of the most suitable grouping depends on the conditions prevailing in each farm, the most common strategy of grouping is determined by the level of production. This practice allows the use of better quality feed in cows of high production, while lower quality feed is used by cows of lower production. Grouping based on the level of production also offers the advantage of being able to feed the individual based on the amount of milk produced by each group so that animals are not fed at libidum. This helps in feed cost savings and avoids problems of underfeeding or overfeeding with all consequent difficulties. Naturally, increasing the number of groups also increases the time required for the preparation of feed. However, increased yield of milk and the economy achieved outweigh these disadvantages.
Also young animals (heifers) usually have lower feed intake and face the challenge of integrating in the herd. Where farmers decide to split the heifers from older and more mature animals, they are able to provide young animals a more nutrient dense ration in a less threatening environment. Increased feed intake and more frequent visits of the animals to the feed-bank, result to higher milk production.
Body Condition Score
An important component of any system maintenance is to monitor properly the body condition score of cows. The Body Condition Score (BCS) must be recorded at the first month of lactation. It is a valuable aid in monitoring the nutrition and management program. The BCS of cows during the first two months of lactation is critical for the level of milk production, while intensive high milk production may be lower in poorly fed cows. In contrast, overfed cows may be prone to metabolic disorders, mastitis or reproductive problems. In most cases, a trained observer will objectively evaluate the herd’s BCS. An effective assessment of a nutrition and management program requires accurate record of production, including production of milk, fat and protein content of milk. The composition of milk production is influenced by the amount of energy supplied, and the amount and type of proteins and amino acids provided. Finally, data on the weight of the animals, the rate of conception, records of diseases and their frequency is very valuable in developing the nutrition strategy.
Nutritional strategies for feeding high milk yield cows
Dairy cows in early lactation are in negative energy balance. That is, the cow does not consume enough nutrients to meet the energy needs of lactation. The feed intake usually lags behind the peak of milk production by 8-10 weeks with a negative effect on BCS.
There are a number of factors that can enhance feed intake. One of the most critical factors is feed availability and the time of feeding. Feed and water should always be available to dairy cows. The feed-bank must be kept clean to avoid deterioration which can reduce feed intake. The length of the feed-bank must be such as to allow all animals to eat simultaneously. The shading of the feed-bank may also be useful as it reduces environmental heat.
Dietary requirements for high milk production
High quality forage such as alfalfa hay and silage are necessary for proper nutrition of dairy cows with high lactation.
Diets containing high levels of compound feed (grain mixtures) can cause metabolic disorders such as rumen acidosis, and may eventually lead to lameness and low fat production. To avoid these problems, energy can also be added to the feed through the addition of rumen protected fat. The protein content should not exceed 16% (on a dry matter basis) for very high milk yield animals, and could be achieved with the addition of synthetic aminoacids. Usually 30 to 35% of protein should be in un-degraded in the rumen in order to maximize the utilization of proteins.
The fiber level must be at least at the minimum required in order to achieve proper functioning of the rumen. One of the most important factors is also the particle size of feed, as feed with very small particle size does not maintain the normal functioning of the rumen. When evaluating a TMR (Total Mix Ration), 20% of the forage must be 4cm long and the remaining 80% must be 1-2 cm long.