Writer: D'Lyn Ford
LAS CRUCES--Like a chef who adapts recipes to ingredients grown locally, New Mexico State University researcher Clinton Krehbiel is developing nutritious menus for New Mexico's dairy cows and range cattle that make the best use of the state's forage.
"My general research goal is to enhance the use of forages, including both native and range and improved or irrigated pastures, by ruminants," said Krehbiel, a ruminant animal nutritionist with NMSU's Agricultural Experiment Station.
Ruminants are cud-chewing animals like cattle and sheep with complex, four-compartment stomachs.
For dairy producers, figuring out how best to feed the cows is no small issue. Feed represents the largest expense, accounting for about 50 percent of total production costs, Krehbiel said.
Also, each year approximately a third or 60,000 dairy cows have to be replaced statewide. Usually, producers send heifers to be raised for two years out-of-state where forage is more plentiful, before bringing them back into the herd. The estimated costs of raising heifers ranges from $700 to $1,200 per animal to two years of age.
To look for a less costly alternative, Krehbiel has teamed up with three researchers at the Agricultural Science Center at Artesia- Carl Barnes, Keith Duncan and Robert Flynn. "We decided to look at whether or not we can raise dairy replacement heifers economically with the limited land we have for irrigated pasture in this state," Krehbiel said.
At the science center, the researchers are studying how heifers grazing an alfalfa and perennial grasses alone or in mixture affects average daily weight gain. They're also considering forage fields.
One grass in the study, Jose tall wheatgrass, is fairly common in New Mexico because it is easy to establish. The cool season grass grows well in March, April and May and recovers again in September and October. On the other hand, Kleingrass--a warm season grass--grows better in warmer months like June, July and August.
"In this first year of a three-year study, the heifers grazing Kleingrass had greater daily gains, but I think production per acre across the entire season will favor the Jose tall wheatgrass," Krehbiel said.
Results from the first year's worth of data indicate that rotational grazing with Kleingrass or Jose tall wheatgrass alone or mixed with alfalfa could be an effective way to raise the dairy replacement heifers in the state. The study will continue for two more years.
Krehbiel said dairy producers also will need to consider whether raising heifers on the state's limited irrigated pastures makes sense for them economically.
In another study, Krehbiel and NMSU researchers at the Agricultural Science Center at Tucumcari and the Clayton Livestock Research Center are looking at different forage grazing options for beef cattle production. Krehbiel said the results of his research could have implications for producers who want to retain more ownership of their steers and raise them through the finishing process to slaughter.
The researchers compared the effects of different winter and summer grazing options on daily weight gain and finishing weights of steers.
"We started the study at the wintering phase--taking calves at weaning in October and growing them either on native range or winter wheat to establish two different growth rates," he explained. "Then in the spring, we either sent the steers directly to the feedlot or grazed them on different forage species."
In the end, the steers that had grazed on the winter wheat outperformed the calves on native range, even though the native range steers made up some of the difference at the feedlot, Krehbiel said. "Also, it appears that any differences in rates of weight gain throughout the summer grazing period are washed out when the steers go into the feedlot."
That means beef producers can choose from a number of forage species for their summer grazing, he added.
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