New Holland, Pennsylvania, is one of the largest and most important (live) goat markets in the US. In 2017, more than 93,000 goats were sold there. The following graph was created using data from the weekly weighted-average market reports published by USDA AMS (LN_LS322). It shows per-head prices for 60 to 80-lb. Selection 1, 2, and 3 goat kids.
The yellow columns show the number of goats that were sold each week (Monday sale). The two largest runs of goats occurred in the two sales that preceded the major Muslim holiday Eid al-Adha (Festival of the Sacrifice). Ramadan began on ~May 26 and ended on ~June 24. Both (Roman) Easter and Orthodox were April 16.
The graph shows significant price differentials for Selection 1, 2, and 3 kid goats. On average, there was a $20-$30/head difference between grades and a $50/head difference between Selection 1 and Selection 3 kids. USDA Selection grades are primarily a muscle score, with 1s being heavy muscled, 2s being average muscled, and 3s being thin muscled. Grades are independent of breeds, though meat breeds obviously are more likely to grade 1 or 2 compared to dairy goats.
Trend lines were added to the graph. In 2017, there seemed to be a general decline in prices as the year progressed. The major religious holidays didn't seem to have a major effect on kid prices. The highest prices were usually observed when the supply of goats was less. In fact, prices went up after Easter and prices for Selection 1 kids were higher after the second Muslim Festival.
In some weeks (especially in the second half of the year), the USDA reports separated out wether (kid) prices. According to the data, there were significant price premiums paid for wether kids of the same weight. The highest price of the year was for wether kids sold at the sale immediately prior to the Festival of Sacrifice, when wethers sold at a $60/head premium compared to non-wethers.
Nothing about the graph or interpretation is scientific or statistical. It is just observations of the raw data.