Scientific Meeting by Mike Mehren Ph.D.

Scientific Meeting
BY MIKE MEHREN

Late last month the Western Section of the Animal Science Society held its annual meeting at the University of Idaho in Moscow. Professors and Graduate students presented summaries of their research. The following were some of the highlights for me. Hopefully you will also think they are interesting.

Dominguez and associates from Mexico studied water quality for baby holstein calves. We don’t wean beef calves nearly as young as done at the dairy, however water quality can be an issue. In this study, the authors compared well water with water that was treated by using a membrane to filter undesirable compounds. Water intake didn’t differ, however feed intake and body weight gain improved tremendously. When beef calves are weaned, water quality should be as high as possible. Clean the tank, pipe water from an open stock pond, don’t allow pools of water in weaning pens. Anything you can do at that time to improve water quality will be rewarded with higher feed intake and gain.

Todd and coworkers studied the effects of different barley and wheat hays and haylage on gains for calves during the winter in Montana. They fed an average of 8 lb/day of cracked barley grain along with the different barley and wheat hay or silage. All cattle were fed 1 lb of a commercial protein supplement. Gains ranged from 2.4 to 2.8 lb/day during a 66 day trial. Feed efficiency favored the barley hay over the winter wheat hay or
wheat haylage. This trial reminds me that we don’t have to feed alfalfa hay to calves to get reasonable gains, however a significant amount of grain will be needed if gains over 2 lb/day are desired (whether feeding alfalfa or not). Please note that grass seed straw will not replace a grass or grain hay for this purpose.

A paper by Dunbar and coworkers from Texas brought home an excellent point about copper supplementation for cows. They tried to determine if copper boluses would improve A.I. conception and bull development. Copper boluses were given to the cows as a source of copper that insures each animal is dosed. The forage was tested for copper only. The feed test found levels of 9 to 11 ppm copper. They did not test for iron, sulfur, or molybdenum, which was a critical omission. In this study the authors saw no benefit from the copper boluses, which would be expected since the forage had 9-11 ppm copper which is virtually equal to the cows requirement of 10 ppm copper in the diet. If they had seen an improvement in AI conception, a case could be made for iron, sulfur, or moly interference. Supplemental copper may be needed in several situations (1) if copper is low in the feed (2) if there are high levels of iron, sulfur, and/or molybdenum in the feed. One situation we see in the northwest is that the copper in the feed is 4-6 ppm that is well below the 10 ppm needed by the cattle. We also see the situation where iron is high (over 500 ppm), sulfur is not usually very high, but in many instances moly is over 1 ppm so that we have a simple copper deficiency made worse by excess iron and molybdenum. Their study showed that giving cattle extra copper without copper deficiency symptoms in the animals such as rough hair coat, breeding problems, or copper deficiency in the forage, is not justified and will only add to expenses.

Ahola and his associates at Colorado State determined trace mineral concentration in forages during different seasons of the year for beef cattle grazing native range. The study was conducted over a 2 year period. The trace minerals did vary from season to season and from year to year...however the variations that they found did NOT change enough to move a trace mineral from ADEQUATE to DEFICIENT or EXCESS when compared to the animal’s needs. For instance:

mineral needed in ppm*	range of trace minerals found in feed ppm**
Selenium	0.1 0.22 – 0.32 - good
Copper	10 1.87 – 5.38 - less than ½ required
Iron	50 200 - 937 - large excess
Manganese	40 58 - 75 - good
Zinc	30 12.4 – 30.25 - low to marginal

* from Nutrient Requirements of Beef Cattle, 1996

** many nutritionists believe that 0.3 ppm Se and 50 ppm Zinc are needed for optimum production and health.

It does appear that sampling for trace minerals during any season can provide information regarding adequacy of the forage to meet the needs of beef cattle. This is NOT true for crude protein and energy. Those nutrients change significantly during the year and must be accounted for if you desire efficient production from your herd.

Fife and others at the University of Idaho continue to study quality characteristics of barley that relate to feeding value. Their studies have conclusively shown that bushel test weight is not related to feeding value. The component of the barley most closely related to barley feeding value is IVTD (in vitro total digestibility). This is a lab technique that uses rumen bugs to digest a feed sample. Many years ago most cattle in the Northwest were backgrounded and finished feeding barley and potato waste. Along came corn and barley lost favor. One big reason was variation. One year or season cattle would perform very well in one location, while at the same time, another feeder would be having nightmares with bloat and performance. Both were feeding barley from the same source, and it tested at least 48 lb/bushel. Who knows what’s going to happen in the future. Corn will continue to be high priced as long as the government continues to support the production of ethanol from corn. Maybe circumstances will favor growing barley again and livestock feeders will get another chance to reinvent the wheel!

Mathis and others from New Mexico State University compared preconditioning using pasture with drylot. The study was conducted for three years. Programs lasted from 42 to 45 days after weaning. Calves weighed about 520 at weaning. All calves were given a series of vaccinations. The calves were then moved to their respective locations. The pasture calves were turned onto native range fields that were not grazed or hayed that year. The standing feed tested 8.3% crude protein. These calves had access to a free choice vitamin-mineral supplement and were fed a 32% protein cube at the rate of 1 lb 4 oz daily. The drylot calves were fed alfalfa hay and a corn/wheat midds pellet.

At the end of 45 days the drylot calves weighed more than the pasture calves. This would be expected because their feed quality was much higher. The drylot calves had a much higher death loss than the pasture calves. This was probably due to stress and ration changes. Financially, the pasture calves netted $45.00/head more due to lower costs. By the time the cattle were finished, the pasture calves netted $111.00/hd more than the drylot calves. With very high feed costs this year, the pasture preconditioning option would certainly justify your consideration.

One of the best parts of any conference is the informal meeting with old friends to catch up on what is happening in their life. I spent time with Dr. Carl Hunt, head of the Animal Science Dept at Univ. Idaho. He gave me a brief tour and talked about improvements to their facilities and staff openings. It was great to hear that the administrators recognize the value of applied livestock research and are willing to spend money to provide for the future. He mentioned an opening in his department for someone whose research area of interest was to determine what could be done with feed and nutrition to improve the merit of a beef carcass. That’s an area that I’d sure like to know more about.

Michael J. Mehren, Ph.D. is a livestock nutritionist from Hermiston who enjoys rubbing shoulders with scientists at least once a year. He may be contacted in his laboratory at mehrens@eotnet.net.