Thursday, September 22, 2011

Final test results

Eighty (80) bucks were delivered to the test site on Friday and Saturday, June 3 and 4.  On these days, weights ranged from 29 to 69 lbs. and averaged 41.0 lbs.  After a 6-day adjustment period, the goats were re-weighed.  The weights recorded on June 10 were the starting weights for the test. Starting weights ranged from 28 to 70 lbs. and averaged 42.5 lbs.

Final weights were recorded on September 15. Final weights ranged from 37 to 71 lbs. and averaged 54.9 lbs.  While on test, weight gain ranged from -9 to +23 lbs. and averaged 12.4 lbs. Average daily gain (ADG) is determined by dividing the weight gain by the number of days of the test (98). 

The goat with the highest rate-of-gain was a Savanna x Spanish buck consigned by Janet & Stephen Garrett (VA). The #34 buck gained 0.235 lbs. per day.  His ADG ratio was 181%, meaning he gained 81% better than the average buck in the test.  Only bucks with ratios above 100 should be selected for breeding.

Weight gains, while not robust, were steady, as evidenced in the graph below.  During the test period, the goats experienced a variety of weather and forage conditions. The test site was dry during the middle part of the test, but very wet during the last six weeks of the test period.


Download report with weight data 
Download report with ADG rankings


Individual fecal samples were collected every two weeks.  The samples were collected directly from the rectum of the goat, unless the goat provided a sample while he was waiting to be worked.

Fecal egg counts were determined by Dr. Dahlia J. O'Brien's lab at Delaware State University. Fecal egg counts are an estimate of the number of adult worms present in the goat's gut. They are a measure of parasite resistance. 

The purpose of this test is determine which bucks are more resistance to parasites. It goes without saying that bucks which shed a lot of parasite eggs should not be kept for breeding. Parasite resistance is a moderately heritable trait, more so than reproductive traits.

During the early and mid-part of the test, fecal egg counts were not very high. While some goats had high egg counts, the majority of egg counts were below 2,000 epg and often 1,000 epg.  Though clinical parasitism could occur at lower levels, 2,000 epg is often considered the level of clinical significance for the barber pole worm.  Fecal coprocultures showed worm eggs to be almost all barber pole worm (Haemonchus contortus).

During the last six weeks of the test, egg counts rose significantly, as a result of the increased rainfall.  In fact, egg counts from the September 15 collection were so high that they eliminated five bucks from the sale.  Before September 15, these bucks were meeting the standards for parasite resistance.

Three bucks in the test showed themselves to be resistant to the parasite challenge under this year's test conditions. The most "resistant" buck was a purebred Kiko consigned by Craig Adams (IL).  The two other bucks with very low egg count data were a Kiko x Boer buck consigned by Luke Miller (IN) and a Full-blood Boer buck consigned by Sherrie Losch (PA).



Download report with fecal egg count data
Download fecal egg count rankings

A few goats required deworming during the test, but for the most part, clinical parasitism was not a problem during this year's test. The high egg counts from the samples collected on September 15 would likely lead to clinical parasitism if the test were to continue for several more weeks. For this reason, goats with FAMACHA© scores of 3 were dewormed on September 15. Anyone taking home a goat from the test site or sale should continue to monitor the goat for signs of internal parasites.

FAMACHA© scores are an estimate of packed cell volume and the need for deworming individual goats.  While not as heritable as parasite resistance (fecal egg counts), selection for parasite resilience is highly recommended. Goats that require frequent deworming as evidenced by high FAMACHA© scores should not be kept for breeding. Bucks should be held to a higher standard.

Two goats had FAMACHA© scores of 1 each time they were checked, resulting in an average FAMACHA© score of 1.0.  The two most resilient bucks in the test were a purebred Kiko consigned by Craig Adams and a percentage Kiko buck consigned by Jeanne Dietz-Band (MD).


Download FAMACHA© and anthelmintic treatment data
Download FAMACHA© rankings


Please direct questions about the data and test to Susan Schoenian at sschoen@umd.edu or (301) 432-2767 x343.