The diet selection of cattle is a difficult area of research, as there are many factors that may influence a steer’s grazing choices in a pasture. However, it’s an important subject that can help shed light on cattle’s understanding of their dietary needs.
Results from a study conducted at the Louisiana State University Agricultural Center suggests that cattle may be able to evaluate diet quality relative to their nutritional needs after they’ve consumed that diet and actively try to correct nutrient imbalances.
In grasslands composed of many forage species, cattle must search out their preferred forage in densely mixed pastures. It becomes difficult for cattle to seek out specific forage they want, and their diet preference cannot be evaluated accurately.
In this study, headed by Guillermo Scaglia, adjacent monocultures of a grass and legume were used to minimize this constraint. Scaglia then determined the preference for one or the other and the role that novelty plays when cattle have never consumed that specific type of forage. Results from this study were published in July-August issue of Crop Science.
The first treatment evaluated cattle’s response to grazing equal proportions of tall fescue and alfalfa when cattle had prior experience grazing only tall fescue. The second treatment evaluated their response to grazing both forages when the cattle had experience with both tall fescue and alfalfa.
The enclosed pastures consisted of 0.54 acres of tall fescue adjacent to 0.54 acre of alfalfa. Each of these pastures were divided into three sub-pastures, using one for the Novelty period, the second for grazing between periods, and the third for the Experience period. The cattle were allowed to move freely between each forage type in the pastures.
Behavior data recorders reported on a variety of cattle activity, including time spent grazing, chewing and idling. The number of bites and chewing cycle were also recorded. Video cameras monitored each pasture to determine which forage was being consumed, and the video was reviewed to document each steer’s behavior every 10 minutes.
Steers spent more time grazing the novel alfalfa than the tall fescue. Cattle never exposed to alfalfa spent more time eating alfalfa than steers that had experience with the forage. However, a partial preference for alfalfa regardless of the cattle’s grazing experience was observed. These results support the theory that domestic cattle have a preference for legumes over grasses.
“This study showed that previously observed diurnal patterns of preference (increased preference for grass in the afternoon) may not always occur,” said Scaglia. “The exact mechanisms that determine overall and diurnal patterns of preference remain elusive; however, this new information may help to narrow down future areas of evaluation.
Research is ongoing at the Louisiana State University Agriculture Center’s Ibera Research Station, where scientists strive to determine the strategies being used by the animal that drive diet selection.
Holly T. Boland, Guillermo Scaglia, David R. Notter, Andrew J. Rook, William S. Swecker and Azenegashe O. Abaye
Grazing Behavior and Diet Preference of Beef Steers Grazing Adjacent Monocultures of Tall Fescue and Alfalfa: II. The Role of Novelty
Crop Science 2011 51:1815-1823
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