July 22, 2020

Monday's Recap - Forages and Pastures Symposium

Forages and Pastures Symposium

By: Dr. Emily Taylor

The Forages and Pastures Symposium began with awarding Dr. Matt Poore with the Extension Award from the American Society of Animal Science. Click here to learn more about Dr. Poore and see his acceptance video of the award.

Dr. Poore’s presentation began by discussing pasture and range management. A well -managed pasture/range is one of the hidden resources that will be key to the future of the world. If management is thoughtful it will lead to:

  • Improved soil health for plant growth
  • Improved water infiltration
  • Improved animal wellbeing
  • Improved economic returns
  • Improved lifestyle

Dr. Poore has delivered many extension workshops on topics that include adaptive grazing, soil and water, and fencing techniques, just to name a few. This has provided multiple opportunities for hands-on training for industry educators, teachers, and students.

The need for forage intake measurements – Dr. Michael Galyean, Texas Tech University

Dr. Michael Galyean’s presentation targeted the need for more accurate forage intake measurements. Systems for describing nutrient requirements of animals are intrinsically composed of 2 parts: 1) Estimates of animal requirements for nutrients and, 2) Estimates of the ability of feedstuffs to meet requirements. Animals require quantities of nutrients, not percentages, however, diets and supplements are typically formulated on a percent basis, thus the ability of feedstuffs to meet nutrient requirements is defined by feed intake.

Unfortunately, forage intake varies greatly depending on environmental changes, supplemental nutrients, social factors, etc. This leaves a gap in knowledge when formulating diets, and using estimates of intake has been the best option thus far. Thumb rules, complex equations based on forage composition, environmental variables, and various animal factors are used to make these estimates. Dr. Galyean stressed the importance of developing methods that yield accurate and precise predictions of voluntary intake for grazing livestock, although said that reliance on the “less-than-reliable’ models and thumb rules is likely to continue to be the standard.

Choosing an external marker for measuring intake and digestibility in ruminants – Dr. Eric Scholljegerdes, New Mexico State University

Dr. Scholljegerdes continued the discussion of unique challenges for ruminant nutritionist - replication of in vitro experiments, modeling, variation in diet and environment, and intake level were a few named. The measurement of intake and extent of digestion is essential for appropriate diet formulation. The use of external markers have been used to measure digesta output, yet the selection of these markers can be challenging. His main focus was on providing guidance in the selection process.

To begin selection, there are a few requirements that the external markers must meet to be considered valid – being inert in the gastrointestinal tract, mixing with the digesta, and having high recover rates in the feces. There are some health hazards to keep in mind for laboratory workers and the animal during selection. The most commonly used markers in the literature are chromic oxide, long-chain alkanes, and titanium dioxide. Dr. Scholljegerdes discussed their positive and negative attributes, which could change depending on the system and management. All three of the external markers have demonstrated adequate fecal recoveries, reasonable estimates of total duodenal, and fecal digesta flows or output. Ultimately, deciding on a marker to use should be based on the ease and accuracy at which analysis can be conducted, dosage rate, minimum dosage frequency, and safety to the user and animal.


Digital Technologies Ease the Burden of Pasture Intake Measurements: A New Hope – Dr. Robert Kallenbach, University of Missouri

A perfect follow-up to our previous presentations, Dr. Kallenbach discussed the use of digital technologies and their role in measuring forage intake. It is well established that the measure of intake is less than reliable, and there is a heavy need for more accurate techniques.

Multiple sensor-based tools including platemeters, digital rules, sonic waves, stereo photography, dual-tuned ultrasound, surround sound, lasers, light bars, and satellite images were discussed as a new hope to pasture researchers, managers and farmers. Dr. Kallenbach believes these tools – coupled with artificial intelligence systems – give creative thinkers new ways to measure, monitor, and manage forage intake in pastures. It is the future!

Sensor-Determined Behaviors and Pasture Intake Estimation in Extensive Grazing Systems – Dr. Paul Greenwood, NSW Department of Primary Industries

Our next presentation on the future of research discussed wearable sensor devices to monitor livestock behavior and location in extensive grazing systems and how they can overcome limitations to collection and use of behavior data. While there are still challenges like device hardware and location on-animal, sensor types and modalities, data power management, and sensor networks to enable measurement of livestock phenotypes in extensive environments – these are being addressed.

Dr. Greenwood’s research devices generate data for concurrent classification of behaviors including grazing, ruminating, walking, resting, and drinking with reliabilities >90%. In addition, they are currently validating estimates of pasture intake using behavior data across a range of environments using chemical markers and/or biomass disappearance. Other sources of variation being evaluated include pasture removal events, classes of cattle, and pasture characteristics. The goal is to determine if more variation in pasture intake can be explained within extensive grazing systems to enhance the development of new traits and applications for precision management.