North Dakota State University - Travis Hoffman (PI)

An opportunity exists for farm flock operations to create and build a market for lamb produced from rams. Direct marketers may be able to capitalize on efficiency of ram growth and merchandise directly to consumers. Additionally, value‐based discounts at processing plants are variant based on seasonality of supply and production. While ram lambs may be discounted at the slaughter facility, is it justified due to marketing ramifications and/or negative (potentially unjustified) flavor perceptions?

Project Objectives

1). Quantify production value improvement for raising rams for merchandising through direct markets.

2). Identify the effect of testosterone level and meat quality characteristics.

3). Determine product yield, carcass cutability, and sensory characteristics for rams and wethers in direct and commercial markets.

                                                                        RETURN

                                                                           

National Sheep Industry Improvement Center

American Lamb Flavor and Direct Marketing of Lamb Originating from Rams

T. W. Hoffman, L. K. Grube, A. M. Long, S. A. Anderson, J. D. Kirsch, and K. A. Vonnahme

Interim Project Report

June 30, 2017

 

 

 

                                                                      Project objectives:

                                                                      1). Quantify production value improvement for raising rams for merchandising through direct markets.

                                                                      2). Identify the effect of testosterone level and meat quality characteristics.

                                                                     3). Determine product yield, carcass cutability, and sensory characteristics for rams and wethers in direct and commercial markets.

 

A total of 20 fall-born (Sept-Oct 2016) Dorset lambs were acquired from the NDSU Sheep Unit for this research.  At birth, the lambs were assigned randomly as either rams or wethers (10 rams, 10 wethers) and appropriately castrated.  Lambs were weighed and growth data (ADG) was calculated on a weekly basis starting in December 2016.  The lambs had their blood drawn bi-weekly starting when the lambs were an average of 113 days old and approximately 100 pounds live weight. Lambs were harvested in three different weight groups (light, medium, heavy).  Light weight group (n = 6) recorded ram weights of 121 lbs., and wether weights of 119 lbs.  Medium weight group (n = 8) recorded ram weights of 158 lbs., and wether weights of 135 lbs.  Heavy weight group (n = 6) recorded ram weights of 183 lbs., and wether weights at 149 lbs.  The lambs were harvested at the NDSU Meats Laboratory carcass characteristics including dressing percent, 12th rib backfat, bodywall thickness, ribeye area, leg score, flank streaking, and Yield and Quality Grade were assessed by university trained personnel.  Carcasses were chilled for two days at 2°C, product was fabricated, and then wet-aged for a total aging time of 14 days.  Lamb loins and boneless legs were collected for further analysis.  Boneless legs were ground and made into 1 oz. patties for sensory analysis.  Carcass traits are currently being analyzed.

Blood collected from live animals, as well as samples collected at harvest will be used for measuring blood testosterone levels. Testosterone levels will be evaluated as an indication of puberty onset.  Correlation to lamb flavor attributes will identify potential pubertal impacts on flavor intensity.  Additionally, another phase of this research can futuristically evaluate lamb quality attributes of loin and leg samples from Spring-born (2016) rams and wethers harvested in Fall 2016 at 0.25” targeted backfat from Hampshire, Columbia, and Dorset breed composition.

Evaluation for meat sensory characteristics which include flavor profile, juiciness, tenderness, and overall liking was completed with assistance from the University of Minnesota’s Sensory Center, Dept. of Food Science and Nutrition.  The sensory panel was comprised of 107 individuals who consume lamb at least once per year. This panel was held over a two-day period, which required the panelists to consume 10 samples of ˝ oz. lamb patties per day.  Three samples of light weight, four samples of medium weight and three samples of heavy weight lambs were served each day, and serve order was randomized.

 Overall liking of ground lamb on a 120 point scale was 73 for wethers, followed by 71 for rams.  On the same scale lamb from light, medium, and heavy weight groups scored 73, 72, and 71, respectively, for overall liking.  Lamb flavor intensity ratings (Figure 1) and off-flavor ratings (Figure 2) by gender and weight (scale of 0-120) showed that while a difference existed between sex class in both light and medium weights, it is not until heavy weight rams of over 180 lbs. that the expected pubertal onset increases lamb flavor intensity and off-flavor.  Consequently, young ram lambs up to 160 lbs. can be harvested at 6 months of age with little to no detriment to lamb flavor, overall liking, and quality of ground lamb products.  In fact, the lamb originating from rams was interpreted as closer to “Just About Right,” with an increased ovine-specific flavor in a contemporary group that was for the most part mild in overall flavor profile, and objectionable off-flavors at moderate or below.  Examples of the consumer survey and the participant demographics have been added below to this report.

A total of $3,765.30 covered one-half of the consumer panel work at the University of Minnesota.  Graduate student stipend will be incurred in 2018.  Pending work for blood testosterone sampling will be incurred July 2017, further analysis with lamb loins for WBSF, proximate analysis of aggregated ground lamb samples, and consumer taste panel work with the breed x sex comparison will be evaluated prior to completion of the project.

 

 

                    Figure 1. Lamb flavor intensity ratings for treatment (ram, wether) by weight (light, medium, heavy); p = 0.010.

 

Figure 2. Off-flavor ratings for treatment (ram, wether) by weight (light, medium, heavy); p = 0.011.

 

  

Tabulation of demographic information

Table 1   Lamb product consumption breakdown for participants

Lamb product consumption

No. of participants

Once per year

24

Once every 3 months

45

Once per month

25

Greater than once per month

13

 

Table 2   Age breakdown for participants

Age

No. of participants

18 to 24 years old

26

25 to 34 years old

44

35 to 44 years old

12

45 to 54 years old

11

55 to 64 years old

8

65 years or older

6

 

Table 3   Gender breakdown for participants

Gender

No. of participants

Male

35

Female

72

 

Table 4   Income breakdown for participants

Income

No. of participants

$15,000 or under

11

$15,001-$25.000

17

$25,001-$35,000

15

$35,001-$50,000

14

$50,001-$65,000

14

$65,001-$80,000

8

$80,001-$100,000

11

$100,001-$150,000

13

Over $150,000

5