Vitamin B Boosts Cattle's Feed Efficiency, Weight Gain

Date: June 09, 1997
Editor: D'Lyn Ford (505) 646-6528, dlford@nmsu.edu

CLAYTON -- New Mexico feedlot operators looking for ways to increase their cattle's feed efficiency may need to add more vitamins to the herd's diet.

In a recent study, scientists at New Mexico State University's Clayton Livestock Research center found that steers gained more weight per pound of feed if they also were fed a ruminally protected form of the B vitamin known as choline, or RPC.

"Most B vitamins break down in the rumen, or first compartment of the stomach. By feeding ruminally protected choline, the vitamin passes through to the intestines," said Michael Galyean, former superintendent of the research center.

The vitamin has been available for a while, but has been fed mostly to dairy cattle, Galyean said. "The results are an increase in milk production and milk fat percentage."

In NMSU's study, 160 feedlot steers were fed varying levels of the vitamin. "RPC is a granular material that can be mixed in with the animals' feed," said Glenn Duff, current superintendent at the research center.

Steers fed a small amount of the vitamin -- one quarter of a percent of their diet -- showed increased feed efficiency and weight gain. "These steers had an 11-percent increase in daily weight gain compared to steers that weren't fed RPC," Duff said. "Also, their feed-to-gain ratio was improved, so they only needed 5.6 pounds of feed to gain one pound versus the 6 pounds needed by steers with no RPC."

The steers fed a small amount of the vitamin also overcame another obstacle -- they began the experiment weighing less than steers in the other groups. "But by the end of the trial, the low RPC steers had passed the other groups in weight gain," Duff said.

He and Galyean agree this increased productivity could have high economic impact for producers and feedlot managers. Duff plans to continue studying how the vitamin contributes to weight gain in cattle.

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**Effects of Graded Levels of Ruminally Protected Choline on Performance**
Item	Treatment				SE^a	Contrast^b
Item	Control	Low RPC	Medium RPC	High RPC	SE^a	Contrast^b
Initial weight, lb	775.1	772.9	773.0	773.9	.74	Q (.10)
Final weight, lb	1,162.7	1,201.0	1,175.6	1,159.7	11.3	C (.10)
Daily gain, lb	3.05	3.39	3.18	3.07	.09	C (.10)
Daily dry matter intake, lb/steer	18.24	19.01	18.75	18.72	.28	NS
Feed:gain	6.03	5.62	5.93	6.11	.13	C (.10)

^aPooled standard error of treatment means, n=four pens per treatment.
^bObserved significance level (in parentheses) for quadratic (Q) and cubic (C) contrasts. NS=non-significant (P>.10).