Influence of Rumen Protected Fat with Methionine on the Performance of Lactating Dairy Cows

Abstract

Flachowsky, G., Raasch, A, Raasch, R. and Möckel, P. 1996. Influence of rumen protected fat with methionine on the performance of lactating dairy cows. J. Appl. Anim. Res., 10: 135–148.

A group feeding experiment was carried out with 248 fresh lactating dairy cows under farm conditions over 107 days. A ration consisting of maize silage, wilted grass silage and concentrate was fed to all the cows However, one group consisting of 124 cows was supplemented with 0.5 kg rumen protected fat with methionine (MAGNAPAC PLUS) per animal per day, in order to see if the protected fat with supplement with methionine could increase milk yield through higher energy intake, without any decrease in protein content of milk. Fat supplementation did not significantly influence body weight changes of cows or measured parameters of reproduction and animal health. Daily milk yield amounted to 25.1 (Control; C) and 26.3 kg (+ Fat; F). Each liter of milk contained protein 33.2 (C) and 31.9 g (+ F), fat 41.8 (C) and 42.6 g (+ F), lactose 47.6 (C) and 47.3 g (+ F) and energy 3.23 (C) and 3.22 MJ (+ F). Milk fat of supplemented cows contained more C _16:0 and C _18:1 fatty acids and less short and middle chain fatty acids than that of control animals. The nutrients and energy yield of the two groups amounted to 833 (C) and 839 g (+ F) for protein, 1049 (C) and 1120 g (+ F) for fat and 81.1 (C) and 84.8 MJ (+ F) for milk energy per cow per day. The average somatic cell count of milk for the two groups was 211 (C) and 190 (+ F) x 10³ per ml. The results of the experiment revealed that the methionine addition to protected fat supplement could not prevent decrease in milk protein content, though the supplement increased daily milk yield, fat content, FCM yield and fat, lactose and energy yield through milk.

Key words:

• Rumen protection
• fat
• methionine
• dairy cows
• milk yield
• milk composition