Feeding of Bypass Fat to Dairy Cattle for Milk Yield

During the initial stages of lactation, the amount of energy required for maintenance of body tissues and milk production often exceeds the amount of energy available in the diet. As a result, body fat reserves are mobilized to satisfy the increased energy requirement. Prilled saturated fatty acids and calcium salts of long-chain fatty acids are effective as rumen-inert fat supplements for lactating cows. Rumen-inert fats, such as calcium salts of long-chain fatty acids or other forms of rumen-bypass fat, are often fed to increase the dietary energy supply. Responses to this supplementation vary. For example, feeding bypass fat to dairy cattle has been reported to increase fat-corrected milk yield, milk and fat-corrected milk yield and milk-fat percentage without affecting the digestibility of other dietary nutrients.

Usually, the ration fed to crossbred cows and high-yielding buffaloes does not satisfy the energy required during lactation. The animals are fed only a limited quantity of cultivated fodder and energy-rich supplements. As a result, animals lose bodyweight very quickly after calving—they could lose as much as 80-100 kg if they’re kept in an open field. Such debilitated animals don’t come in heat unless they recover their lost body weight. This leads to delayed conception after calving and longer inter-calving intervals. Animals also produce less milk during this period. Overall, it is a significant economic loss to milk producers.

Raw edible oils, if given beyond a certain proportion as a source of fat, may adversely affect fibre digestion and bind divalent mineral ions. Therefore, it is necessary to supplement fats in a form that can provide energy without affecting fibre digestion in the rumen.

Feeding Bypass fat gets digested in the abomasum at acidic pH, without interfering with the fermentative digestion in the rumen. Fat supplements in this form are termed as bypass fat, which can help in improving milk production, body condition score, and reproduction efficiency. Bypass fat is the most energy-dense nutrient available that does not affect fibre digestibility, feed intake or the absorption of magnesium and calcium. Rumen-inert fat (calcium salt of fatty acid) is partially resistant to bio-hydrogenation by rumen microbes and reduces the risk of metabolic acidosis.

Characteristics of Bypass Fat

Bypass fat comprises fatty acids associated with calcium ions, instead of a glycerol backbone. When calcium is associated with fatty acids, the fat supplement formed is rumen-inert. Bypass fat has low solubility in the rumen and is less susceptible to biohydrogenation. However, it dissociates in the acidic pH of the abomasum, and the fatty acids and calcium are set free for absorption. Feeding bypass fat to lactating animals increases milk and fat yield and ensures early conception.

Benefits of Bypass Fat for Dairy Cattle

Ideal energy-dense supplement for lactating and pregnant animals to overcome negative energy balance. Enhances peak milk production and persistency of lactation in dairy cattle. Fulfills the nutrient requirements of high-yielding animals. Reproductive performance can be enhanced because the animal can return to positive energy balance sooner, which affects follicle size, ovum fertility and progesterone levels. Decreases metabolic disorders such as ketosis, acidosis & milk fever. Increases productivity and the productive life of animals.

The FAQ on Bypass Fat

What is bypass fat?

Dietray fat, which is not degraded in the digestive tract (rumen) of animal, but gets digested in the lower alimentary tract is known as bypass fat.

What are the synonyms of bypass fat?

Rumen protected fat, Calcium salts of long-chain fatty acids, Calcium soaps.

Why supplement bypass fat to dairy animals?

Immediately after calving, there is a huge loss of energy through milk, which the regular feed intake cannot satisfy. Therefore, animals remain in negative energy balance. This affects milk production, reproductive performance and the overall health of the animal. High-producing dairy cattle are more likely to experience these effects. Bypass fats are a rich source of energy. Bypass fats are also a good source of calcium. Supplementation with bypass fat improves milk production, reproductive performance, and overall health.

Why oil can not be included instead of bypass fat to get more energy?

Oil causes digestive problems in animals. Oil is degraded in the upper part of the digestive tract (rumen) and therefore provides less energy than bypass fat.

What are the advantages of the supplementation of bypass fat to dairy animals?

Keeps animals in positive energy balance. Increases milk yield (up to 20%). Increases milk fat content. Maximizes peak milk yield and lactation days. Improvement in reproductive performances. Prevents post-partum weight loss. Improves general body condition. Protects from heat stress.

Is the effect of the supplementation of bypass fat similar in all types of dairy animals?

Effects tend to be greater in high yielding dairy cattle (cows producing more than 15 liters milk/day and buffaloes producing more than 8 liters milk/day). Effects tend to be greater in the early stages of lactation (0-90 days) than in the later stages of lactation (91-150 days). Effects tend to be seen more in Holstein cows.

How much bypass fat to be supplemented?

15-20 g/ kg milk production/ animal/ day.It can be supplemented to dairy cattle 15 days before to 150 days after parturition.

How bypass fat is supplemented?

Bypass fat can be mixed with a concentrate mixture. It can be given as a single dose or in divided doses.

How does bypass fat works?

Bypass fat contains an unsaturated fat related to calcium particles, rather than a glycerol backbone. The association with calcium salt and fatty acid means the fat supplement has low solubility, is less susceptible to bio-hydrogenation and remains inert in the rumen. However, in the acidic pH of the abomasum, it dissociates and the fatty acid and calcium are set free for absorption. The fatty acids are more digestible in the duodenum due to high acidity, bile acids, lysolecithin, and fatty acids.

Why is it essential to supplement choline with bypass fat?

Normally, choline can be synthesized adequately, but the supply of choline in lactating dairy animals may be insufficient (Pires and Grummer, 2008) [23]. Dietary choline must be supplemented in the protected form because it gets degraded rapidly in the rumen (Elek et al., 2008) [8]. Choline is a constituent of phospholipid and acts as a methyl donor. It enables fat export from the liver by playing a vital role in the synthesis of very low density lipoprotein and consequently, the metabolism of fat for energy and milk production. A significant decrease in serum NEFA level has been reported upon the feeding of rumen-protected choline.

What is the effect of bypass fat on reproduction?

Supplementation of Ca-LCFA in the diet has a positive effect on the reproductive performance of dairy cows, which is further dependent on the specific fatty acid profile of the calcium salt. Feeding Ca-LCFA increases the pregnancy rate and reduces open days. It is suggested that an improved energy balance results in an earlier return to post-partum ovarian cycling; an increase in linoleic acid may provide an increase in PGF2α and stimulate a return to ovarian cycling and improve follicular recruitment; and an increase in progesterone secretion either from improved energy balance or from altered lipoprotein composition from dietary fat improves fertility.

Bypass fat at NDDB

Fatty acid composition of palm fatty acid distillate (PFAD) based bypass fat:
Name of Fatty Acid Content
Palmitic acid
(C16:0) 46-49
Oleic acid
(C18:1) 36-38
Linoleic acid
(C18:2) 7-8
Stearic acid
(C18:0) 4-6
Myristic acid
(C14:0) 1.1-1.4
Lauric acid
(C12:0) 0.2-0.3

Specification of Bypass Fat

Characteristic Requirement
Fat content
Calcium content
Light brown to pale yellow
Physical appearance
Free-flowing granules

Dr. Rajesh Kumar Singh

Jamshedpur, Jharkhand, India
Mob. No: 9431309542
Email ID: [email protected]