Enhancing the sustainability of grass-fed beef production in Hawaii via carcass and meat quality improvement

Enhancing the sustainability of grass-fed beef production in Hawaii via carcass and meat quality improvement

Summary

     Interest in locally produced, grass-fed beef has increased tremendously among the general public, chefs, and agricultural community in Hawaii as a sustainable model for beef production and also to increase the level of food self-sufficiency for the island state. Despite this interest, our studies and others have shown that meat quality of grass-fed beef is inconsistent, potentially limiting the long-term economic sustainability of grass-fed beef production. It was identified that information on carcass and meat quality characteristics and the nutritional quality of pastures on which grass-fed beef are produced would help to develop strategies of improving carcass and meat quality characteristics of grass-fed beef in Hawaii. Therefore, the project was designed 1) to evaluate growth performance, and carcass and meat quality characteristics of pasture-finished cattle in selected local ranches of Hawaii, and 2) to evaluate characteristics of pastures on which cattle are finished in collaboration with local ranchers.

     During this project period, three hundred fourteen rib eye steak samples of grass-fed cattle were collected, and their cooked-meat tenderness were examined by shear force measurement to investigate potential factors affecting grass-fed beef tenderness. Results showed that the tenderness of current grass-fed beef in Hawaii had significantly improved during the last 10 years. Younger slaughter age appeared to be an important factor in improving the tenderness of grass-fed beef. Marbling, beyond a certain level (probably high slight), did not appear to influence the tenderness of grass-fed beef. Sixty-two forage samples from pastures of four participating ranches were also collected during this project period in two different seasonal conditions. The samples represented three different forage types – kikuyu grass, guinea grass, and leucaena. Processed forage samples were sent to a commercial lab for nutrient profiling using near-infrared reflectance spectroscopy. Preliminary data analysis indicated that pasture type and season had a significant effect on some nutrients in these forages. The relative feed value of leucaena was almost twice the value of kikuyu or guinea grasses. Leucaena incorporation in pasture significantly improved average daily gain of cattle from weaning to slaughter, resulting in significantly shortened grazing period in pasture when cattle were slaughtered at a constant body size, thus suggesting that leucaena incorporation in pasture can improve the efficiency of grass-fed beef production in Hawaii.

Objectives/Performance Targets

1) To evaluate growth performance, carcass and meat quality characteristics of pasture-finished cattle in selected local ranches of Hawaii

2) To evaluate characteristics of pastures on which cattle are finished

Accomplishments/Milestones

Examination of carcass traits and tenderness of grass-fed beef

        Three hundred fourteen rib eye steak samples of grass-fed cattle were obtained from two slaughterhouses on Hawaii Island between November, 2013 and June, 2015 to examine meat tenderness of grass-fed beef of Hawaii. The cattle were mostly from ranches participating in the SARE project, as well as some from non-participating ranches. The rib eye steak samples were collected at the 12^th rib a few days after slaughter, vacuum-packed and aged for 2-3 weeks from the slaughter date and stored at -20^oC until measurement of shear force value of cooked steak and other parameters associated with meat quality characteristics. Approximate animal age based on teeth observation, sex, carcass weight, breed type based on skin color, and the levels of marbling were evaluated post slaughter by personnel at the slaughterhouses. The research team also evaluated the carcass characteristics of selected cattle in the University of Hawaii, Manoa.

       Shear force measurements were carried out periodically when about 70 samples had been collected. The shear force measurements were conducted using a Warner-Bratzler machine (G-R Manufacturing, Manhattan, KS) following the protocol of the USDA-ARS Meat Animal Research Center. Results of data analysis showed that the tenderness of current grass-fed beef has significantly improved during the last 10 years. Younger slaughter age appeared to be an important factor in improving the tenderness of grass-fed beef. Marbling, beyond a certain level (probably high slight), did not appear to influence the tenderness of grass-fed beef. Current results suggest that the CTAHR grass-fed beef research program and extension efforts to communicate research results with ranchers and other stakeholders have helped to improve the tenderness of Hawai‘i grass-fed beef.

      Currently, fatty acid profiles of selected beef samples are being analyzed to examine whether the fatty acid composition is associated with types of pasture.

Examination of nutritional profiles of various pastures on which cattle are finished

      Sixty-two forage samples in pastures of four participating ranches were collected in December, 2014 and August, 2015, representing two different seasonal conditions. The samples represented three different forage types – kikuyu grass and guinea grass and leucaena. Samples were processed and sent to a commercial lab (Dairy One, Ithaca, NY) for nutrient profiling using near-infrared reflectance spectroscopy. Preliminary data analysis indicated that pasture type had a significant effect on concentration of some nutrients in these forages. The crude protein content of leucaena was almost double of kikuyu or guinea grasses on a dry matter basis, resulting in almost a two-fold increase in relative feed value (RFV) of leucaena as compared to those of kikuyu or guinea grasses. Leucaena incorporation in pasture significantly improved average daily gain (1.64 vs. 1.18 lb) of cattle from weaning to slaughter, resulting in significantly shortened grazing period in pasture when cattle were slaughtered at a constant body size. Forage data analysis is currently undergoing. Upon completion of data analysis, the results will be summarized in various formats to disseminate our findings to grass-fed beef producers and professionals in this field.

Meetings with participating ranchers

      The participating investigators (Dr. Yong Soo Kim, Dr. Rajesh Jha, and Mr. Glen Fukumoto) together visited participating ranchers in Hawaii Island (Mrs. Jill Mattos, Mr. Pono von Holt, Mr. Jerry Egami, and Mr. Stephen DeLuz) to get help in sample collection, to explain the progress of the project, and discuss preliminary results on carcass and tenderness analysis and forage analysis in December 2014 and October, 2015.

      Forage data analysis will be completed in May, 2016. A workshop is planned during the summer 2016 to disseminate our results to ranchers, and industry people associated with the grass-fed beef production.

Impacts and Contributions/Outcomes

      A workshop was organized by the SARE project team to disseminate our findings and to discuss issues with grass-fed beef producers in association with grass-fed beef production. The workshop was held on July 25, 2014 at the North Hawaii Education and Research Center, Honokaa, Hawaii County. There were three presentations from our SARE project team (‘Forage quality and cattle performance’, ‘Evaluating carcass quality’, ‘Science of beef tenderness and product development’) and tenderness testing demonstration, along with discussions on beef quality, tenderness and pricing. There were 23 participants in the workshop.

      A presentation entitled ‘Nutrient profile of leucaena and guinea grass and growth performance and carcass quality of beef cattle grazed on these pastures in Hawaii, was made at the 2015 Spring CTAHR Symposium by Ms. Kayla Butler, a graduate student advised by Dr. Jha and partly supported by the SARE project.

      An invited presentation entitled ‘Improving meat quality characteristics of grass-fed beef in Hawaii’ was made by Dr. Yong Soo Kim at the 1st International Symposium on ‘Beef Sciences and Industry Technology Development’ sponsored by Yanbian University, China on October 10, 2015. The presentation introduced grass-fed beef as a part of sustainable agriculture in Hawaii, as well as various factors associated with the tenderness of grass-fed beef.

      An extension publication summarizing parts of our results on Hawaii grass-fed beef was completed: Yong Soo Kim, Glen Fukumoto, Matthew Stevenson, Mark Thorne, and Rajesh Jha. Carcass Traits and Tenderness of Hawaii’s Grass-fed Beef. UH-CTAHR, LM-29, December 2015.

Collaborators: