A King County Superior Court judge declined Friday to immediately rule on a challenge to the voter-approved $15 an hour minimum wage requirement for airport workers in Seattle-Tacoma International Airport.

Judge Andrea Darvas said she'll issue a ruling with reasoning after Christmas Day but before January 1. Parties in the case had been expecting a ruling Friday.

The measure is scheduled to go into effect on January 1.

Last month voters in the city of SeaTac narrowly approved the measure, which would require a $15 minimum wage, a handful of paid sick days and other standards to around 6,000 workers at the airport and related industries, like hotels and rental car companies.

However, the legal fight over the measure is not expected to end with Darvas' ruling. An eventual appeal to the state Supreme Court could come from either side, depending on her ruling.

The challenge to the newly approved measure is being led by Alaska Airlines Group and other businesses. They say that an initiative approved by city residents doesn't have power over the airport, which is operated by the Port of Seattle. The Port of Seattle, a public entity, agrees.

Alaska Airlines Group also says state law prohibits initiatives from packaging laws. So they're arguing that the multiple requirements in the measure, such as the minimum wage and paid sick days, constitute packaging multiple laws into one initiative.

A federal appeals court on Friday removed a temporary ban on domestic horse slaughter, clearing the way for companies in New Mexico, Missouri and Iowa to open while an appeal of a lawsuit by animal protection groups proceeds.

The 10th U.S. Circuit Court of Appeals in Denver lifted the emergency injunction it issued in November after The Humane Society of the United States and others appealed the ruling of a federal judge in Albuquerque. The judge said the U.S. Department of Agriculture followed proper procedure in issuing permits to Valley Meat Co. in Roswell, N.M., Rains Natural Meats of Gallatin, Mo., and Responsible Transportation in Sigourney, Iowa.

The appeals court's order Friday said the groups had "failed to meet their burden for an injunction pending appeal."

Blair Dunn, an attorney for Valley Meat and Rains Natural Meats, said the order lifts the emergency status of the case, meaning it will likely be months before a final decision is issued.

Dunn said the plants are ready to open, although they could agree to remain shuttered if the plaintiffs agree to post a sufficient bond to cover the companies' losses should they ultimately prevail.