Benefits And Recommendation For Feeding Fats To Dairy Cows
Feeding fats to dairy cow wasn't common a few decades ago. Recently however, it has become increasing popular for several reasons. The first and main reason is that fats contain high amount of energy. During lactation phase, dairy cows require high amount of energy. If dairy cows are unable to meet their daily energy requirements during lactation phase, there will be many adverse effect such as losing weight, reduced amount of milk produced and shorter life span. The second reason is feedstuffs high in fat have become more available and economical.
Benefits Of Feeding Fats
Dairy cows need a tremendous amount of energy especially during lactation phase. A typical dairy cow weighing around 1,400 lb (635kg) and producing 70lb/day (31kg/day) of milk with 3.6% fat and 3.3% protein requires roughly 33 Mcal/day of net energy for lactation (NEL). That amount is equivalent to about 26 times more energy than a person consuming a recommended 2,000 calorie diet.
Feeding fats to the milking herd increases the amount of energy contained in the diet. Fats contain approximately two times more energy than carbohydrates. For example, fats contain approximately 2.65 Mcal NEL/lb compared to 0.95 Mcal NEL/lb found in corn grain or 0.63 Mcal NEL/lb in excellent quality alfalfa hay. By adding fat, the feed would be higher in energy density. Thus, more energy can be packed into each mouthful of feed a cow eats. At the same time, adequate dietary effective fiber is needed to maintain rumen function.
Some scientists even suggested that feeding fats during early lactation phase will improve reproductive performance and may decrease the incidence of ketosis. Adding fat into grain mixes may also reduces dustiness of these feeds.
The Effects Of Feeding Fats On Feed Intake And Milk Production
Feeding fat to lactating cows has been proven to increase milk production substantially. This is mainly due to an increase in peak milk production as well as an increase in persistency of the lactation curve. First-calf heifers do not respond as well as mature cows to the addition of supplemental fat.
Generally, the milk fat percentage has shown to increase when the recommended amount of supplemental fat is fed to dairy cows. With that being said, feeding large amount of unsaturated fat has shown to have negative effects such as decrease in fiber digestion or in fat milk percentage.
In some cases, studies showed that milk protein percentage decrease by one to two-tenths when feeding supplemental fat. This decrease seems to occur in the casein fraction.
Responses in dry matter intake varies when feeding dairy cows with supplemental fat. In trials using whole cottonseeds, whole soybeans or tallow, some studies have shown decrease in dry matter intake, whereas others have shown increase in dry matter intake. In some of these trials where dry matter intake has decreased, the amount of energy consumed has remained constant or increased slightly to account for the increase in milk production. Decreases in feed intake may be seen especially when the amount of fat in the diet exceeds the amount needed for milk fat synthesis.
Recommendations For Feeding Fats
When introducing fats to dairy for for the first time, cows should be allowed enough time to adapt slowly to the new ration.
Nutrient content of oilseeds, tallow and greases can vary between sources and quality. Purchaser should always analyse the nutrient content to ensure it is up to standards.
Type of supplemental fat added to the dairy cow's diet should be in a form that can be easily and economically handled in the farmer's feeding system.
When supplemental fat is added, the % of calcium and magnesium in the total diet should increased to 0.9 - 1.0% calcium and 0.3 $ magnesium (DM basis). Also, the amount of undegradable protein should be increased by 1% for each addition of 3% fat to the diet. (For each 1 Mcal of NEL from added fat, add 72g of undegradable protein.)
The total fat percentage from natural fat resources should not exceed 5% in a lactating cow's diet. Natural fat sources include forages, cereal grains, oilseeds and tallow. Approximately 2-3% would be supplied by forages and cereal grains, an additional 2-3% would be from oilseeds and tallow. Finally another 2-3% of fat can be supplied from speciality or ruminally inert fats. Therefore, a total of 8% of fat is recommended in a dairy cow's diet. Exceeding these recommendations is highly discouraged as it may decrease the fiber digestion and cause the milk fat % to drop.
High-producing herds are the most likely to benefit from the addition of fat in the diet. In these herds, fiber contents are at a minimum with large amounts of grain being fed. Fat can be used to increase the energy density of these diets. In herds where low quality forages are fed, the most economical approach would be to increase the energy density of the diet. In a long run, this can be accomplished by harvesting high quality forages. However, the short term solution would be to feed more grain and fat to provide sufficient energy to the cow.
When considering to add fat to a diet, formulate a ration that is a) economical b) allows cows to produce milk to their genetic potential c) fits a farmer's feeding system