Most anthelmintics are safe for use throughout pregnancy, but precautions and contraindications on package inserts should be heeded. In general, anthelmintics Anthelmintics should not be administered to mares during the first 60 days of gestation (organogenesis). Parasite control programs should be tailored to meet the particular farm needs. Also see Gastrointestinal Parasites of Horses Gastrointestinal Parasites of Horses . Pregnant mares should be administered ivermectin or a benzimidazole 1–3 days before foaling to prevent lactogenic transmission of Strongyloides westeri, which can cause diarrhea in young foals.
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Also see pet health content regarding routine health care for horses Routine Health Care of Horses In addition to properly feeding and exercising your horse, other aspects of general care are needed to keep your horse healthy throughout his or her life. These include routine veterinary care... read more and the breeding and reproduction of horses Breeding and Reproduction of Horses Mares reach puberty at about 18 months of age and undergo an estrous, or heat, cycle. Mares go into heat repeatedly during the breeding season, which usually continues while day length is long... read more .