Whelping & Weaning (April - June)
Gestation varies from 40-70 days (due to a delayed implantation).This period may be shortened by extending the daylight period with the use of lights immediately following breeding.
In preparation for whelping, nests are prepared with ample bedding and the females are kept comfortable.Unnecessary stresses and noises are avoided.
Females give birth to an average of 5-6 kits (maybe higher, depending on colour-type).The newborn kits are very tiny (the size of your pinky finger), have no fur, and cannot see.
Females spend most of their time in the nest boxes caring for their kits.Ranchers check nest boxes regularly to make sure that the females are in good health and lactating properly, and that all of the kits are kept warm, getting ample milk, and are growing well. Female health is also monitored by feed consumption.A sudden decline in consumption is a sign that the female (and her litter) requires immediate attention.
Sometimes it is necessary to foster kits if litters are large and there is not an ample supply of milk to support all of their needs for growth. Sometimes ranchers foster entire litters if the female is sick, not lactating properly, or is not taking good care of her kits.Female mink are normally very accepting of fostered kits.
Throughout this period, the correct balance of fat and protein in the diet are critical for proper lactation (thus kit growth) and maintenance of the females.Females are fed based on the size of their litter, the age of the kits, and their physical condition.
Feed is introduced to kits between 4-5 weeks of age.They quickly transition to a diet consisting more of feed and less of mother's milk. The kits will also become familiar with the water source (water dish or nipple).
During this period, it is important that nests are kept dry, that feed and water is readily available, and that the kits are content.
At approximately 6-8 weeks of age, the kits are weaned from their mothers.When they are capable of maintaining body heat in smaller groups, they will be placed into pairs.
Growth & Furring (July - October)
The main activity during this period is feeding.The feed rations are designed to promote growth.Often mink are fed multiple times a day to ensure that there is always fresh feed available.
In July all mink (kits and adult breeders) are vaccinated.In Canada we use a 4-Way vaccine, protecting against Distemper, Pseudomonas, Enteritis and Botulism.This task can be very time consuming, however, is very important.
In August growth of the winter fur begins.The diet changes to support hair growth.Mink fur has two components, the longer shinier guard hair that is most visible, and the shorter softer underfur that is hidden beneath.
At the end of August, the mink's bodily development has by and large been completed. Subsequent growth consists primarily of fat.
It is important to keep nest boxes clean, the mink well fed and content.This is critical in protecting the valuable fur coat.
By fall the fur thickens (more hair per square inch).Fur growth begins at the tail and continues up the back and to the head. The winter furring process is not stimulated by cold temperatures, butrather by the shortening of the daylight period.This change stimulates the production of melatonin, a hormone that activates hair follicles to produce new hair. During furring the minks' skin appears blue.When the fur growth is complete the skin changes to a creamy white and the fur is considered to be prime.