In early lactation dairy cows are not able to ingest enough energy to meet requirements. One may fill this energy gap by supplying rumen-protected fats. Nowadays, there are several bypass products on the market, but it is difficult for the farmer to judge their efficacy. We examined the bio-availability of 2 calcium-soaps of palm fats, Orffa Fat (OF) and Megalac (ML) and 2 palm fat prills, Bergafat F-100 (B100) and Bergafat T-300 (B300) containing fatty acids and fat, respectively. Rumen bypass and gut availability was determined by means of the in situ nylon bag technique. Per product eight bags (LxW: 7 x 3 cm, pore size: 37 µm) were filled with 1 g sample. The bags were put in a perforated cylinder and incubated in the rumen of a lactating cow for 8 h. After incubation, bags were machine-washed, freeze-dried and weighed. A few days later, the bags with bypass product were first soaked in a solution of pepsin in 0.1 N HCl during 1 h and then immediately inserted in the duodenum of the same cow. After passage through the intestines, which lasted for 9 to 11 h, bags were recuperated in the feces, intensively washed, freeze-dried and individually weighed again. On DM-basis, rumen bypass amounted to 95% for OF and to 100% for the other products, meaning that protection against rumen degradation was very effective. Gut availability on the other hand was very variable among products amounting to 83.5 ± 4.0, 43.7 ± 3.4, 12.1 ± 4.2 and 13.9 ± 2.0 % for OF, ML, B100 and B300, respectively. Based on the fat content in the product, it can be calculated that OF, ML, B100 and B300 provide 17.2, 8.9, 2.9 and 2.8 MJ/kg net energy for lactation, respectively. These results indicate a clearly better efficacy of calcium-soaps than of hardened fat prills. It was hypothesized that the higher availability of OF as compared to ML is related with its finer particle size, amounting on average to 1.15 and 2.53 mm, respectively.
|Titel||Book of Abstracts of the 65th Annual Meeting of the European Federeation of Animal Science|
|Uitgeverij||Wageningen Academic Publishers|
|ISBN van geprinte versie||978-90-8686-248-1|
|ISBN van elektronische versie||978-90-8686-799-8|
|Status||Gepubliceerd - 25-aug-2014|
|Evenement||65th Annual Meeting EAAP 2014 - Kopenhagen, Denemarken|
Duur: 25-aug-2014 → 29-aug-2014