Monday, September 9, 2013

Final evaluation

On September 5, the goats were evaluated for structural correctness and reproductive soundness. To be eligible for the sale, bucks must meet minimum standards for these two criteria.

Scrotal circumference was determined using a measuring tape. Scrotal Measurements ranged from 14.0 to 28.5 centimeters and averaged 22.4 + 3.7 centimeters. The median scrotal circumference was 23.0 centimeters.

Since weight has a large effect on scrotal circumference, the bucks were divided into weight groups in order to evaluate their scrotal measurements. A ratio was determined for each buck by dividing the buck's scrotal circumference by the average SC in his weight group. For example, a 57-lb. buck with a SC ratio of 114 percent has a scrotal measurement that is 14 percent larger than the average buck in his weight group (50-59 lbs).

While minimum requirements have not been established for bucks of different breeds and ages, it is generally recommended that bucks with larger scrotums be favored for breeding. In other species, scrotal circumference is correlated with ovulation rates in female progeny. None of the bucks in the test were determined to have testicle abnormalities.

The teat structure of each buck was examined. Most of the test bucks have two functional teats. Only a few bucks have extra teats or teat defects.  While producers and breed associations may differ in their opinions regarding extra teats, it is generally recommended that bucks with two "functional" teats be retained for breeding. Teat number and structure are heritable traits in goats.

Bites (mouths) were also examined. All of the bucks had normal (N) bites. Bucks with over- or undershot jaws should generally not be retained for breeding. Slight jaw defects are usually not problematic, although bucks should always be held to a higher standard than does.

The hooves of each buck were examined for hoof growth, color, and morphology. Hoof growth was evaluated using a scale of 0 to 5, with 0 representing no growth and 5 representing excessive growth. Hoof growth ranged from 0 to 2, with most of the bucks having minimal hoof growth.

Some bucks had "pockets" in their hooves. Pockets can provide an entry point for disease-causing bacteria. One buck had extremely large pockets on his front hooves and should not be retained for breeding. Only one buck was noted having for abnormal hoof growth.

In sheep, light-colored hooves grow faster and seem to be more prone to hoof ailments, while dark-colored (black) hooves are harder and less disease-prone. The color of each buck's hooves is noted in the report.

The bucks were scored for overall structure and conformation (feet and legs) by observing them while they were standing and moving. Most of the bucks were considered to have average conformation, with no functional defects. A few bucks were noted as having "good" structure. A few bucks were cow-hocked.

USDA Selection 2
For the first time, bucks in the test were given a frame score. The frame scores used were small, medium, and large. They serve as an estimate of a buck's final frame size, with large frame bucks expected to reach a larger mature size than medium frame bucks and medium-sized bucks expected to achieve a larger mature size than small-framed bucks. It usually takes three years for a buck to reach his full mature size.

For the first time, the test bucks were assigned a USDA grade. The USDA grades are Selection 1, 2, and 3. They are essentially a muscle score, with number 1 goats having superior muscling, number 2 goats having average muscling, and number 3 goats having inferior muscling. At sale barns, there can be a considerable price differential among Selection 1, 2, and 3 goats.

Most of the goats in the test were graded Selection 3. There were a few bucks that could slip into the number 2 grade. A few bucks were deemed unfit for market. They received a grade of U (unthrifty). USDA grading is subjective. If the bucks were on a higher plane of nutrition, it would be possible for many of them to achieve a grade higher.

The rib eye areas, as determined by ultrasound, are probably a better indication of carcass muscling.  While ultrasound measurements may not accurately predict the size of the rib eye muscle in an individual goat, they seem to be accurate for making comparisons.

Download supplemental report