Beet pulp is a byproduct from the processing of sugar beets. Herbicides or pesticides are not sprayed directly on beet pulp after the sugar beet processing. However, as with most agricultural plant crops, there are plant diseases, insects and weed issues that threaten sugar beet crops and therefore sprayed applications are not uncommon during the growth phase of the plant.
Regarding your second question, beet pulp is naturally dry and prickly. Some companies that sell it in sacks will add molasses to soften the product and of course there’s the benefit of flavor enhancing. In horse feeds, beet pulp is softened by the moisture from other ingredients as well as from the molasses and oils that may be added to the product. All horse feeds list the ingredients on the bag, so if molasses has been added it will be on there.
I suggest you read my fact sheet on Nonstructural Carbohydrates in Dr. Bray’s Corner. Our industry is in overdrive with concerns of starch/sugar and unfortunately many myths are circulating. Obviously I am not familiar with your horse’s particular situation, but if your horse has been clinically diagnose with IR then perhaps a comprehensive review of your horse’s diet may be appropriate to ensure their nutrient requirements are met while minimizing the nonstructural carbohydrate intake.