Horns of cows are removed because they can pose a risk to livestock handlers, other animals and to the bearers of the horns themselves (horns are sometimes caught in fences or prevent feeding).

In the United States, an estimated 80% of all dairy calves (4.8 million per year) and 25% (8.75 million animals) of beef cattle are dehorned every year (Carlson et al., 2016). Dehorning of adult cattle is associated with increased risks of sinusitis, bleeding, prolonged wound healing, and infection (American Veterinary Medical Association, 2014). There is evidence that dehorning is painful for the animal: physiologic, neuroendocrine, and behavioral changes indicative of pain and distress are observed following dehorning (ibid.).

Fortunately, gene editing technologies can be used to create hornless cows. In 2016 Alison van Eenennaam and her research team at UC Davis, in partnership collaboration with Tad Sonstegard and his Minnesota-based company Recombinetics, used genome-editing to make cattle that don’t grow horns.

However, van Eenennaam's 2019 article argues that the currently proposed U.S. regulation of gene-edited food animals is "not fit for purpose" as it has made it virtually impossible to commercialise gene-edited food animals. Although the FDA has introduced new ventures to expedite advancements in the regulatory approval process of innovative animal products, it is unclear when hornless cows can be successfully commercialised.

When will the milk of cows whose DNA is intentionally altered to be hornless be for sale, for human consumption, in the United States?

Resolution

This question resolves as the date when the milk from cows whose DNA is intentionally altered to be hornless using modern molecular technologies, that do not involve selective breeding, are first for sale for purposes of human consumption, in any state of the United States. For the purpose of this question, an organism with intentionally altered DNA are those with alterations introduced into the DNA of an organism using modern molecular technologies, such as genetic engineering (also referred to as recombinant DNA technology) and genome editing.

Examples of the use of modern molecular technologies that qualify for positive resolution is the transcription activator-like effector nucleases (TALENs) to swap the version of the POLLED gene that causes horn growth in dairy cattle into the hornless version that naturally exists in beef cattle. This specific example was used in the approach reported a Nature correspondence (Carlson et al. 2016).

The specific genomic alternation needs to result in cows never developing horns at least 25% of the time for male cows. The question resolves on the basis of credible media reports. Modified animals used to study human diseases or used for drug testing do not count toward resolution.

If the question does not resolve before October 2nd, 2035, it resolves as "> Oct 2, 2035".