Muskrat Artificial Breeding Experience and Technical Key Points

I. Preliminary Preparations for Muskrat Breeding

A. Cage and Pen Preparation

Currently, the vast majority of artificially raised muskrats are kept in outdoor pen-style housing. The pens used for artificial muskrat breeding in various regions include flat pens, vertical pens, multi-tier pens, juvenile rat pens and simple pens, etc. A few are also kept indoors in cages. Outdoor pen-style housing is relatively economical and practical, and is easy to adopt for household raising in rural areas, but it occupies a relatively large area, and the water pools used for raising are also easily frozen and damaged in winter. Indoor cage raising has a high stocking density and is suitable for urban areas or experimental raising.

When outdoor pen-style housing is adopted, there must be a breeding site. The site must have a surrounding wall, and a simple shed must be built over the site to block rain and snow and prevent exposure to the scorching sun. Inside the shed, the pens used for raising muskrats are then placed. The breeding site should be chosen in a place with sufficient water sources, shelter from the wind, a quiet environment, freedom from disturbance by people and livestock, and relatively far from highways. In order to avoid mutual infection, muskrat breeding sites must be far away from livestock farms and poultry farms, generally required to be more than 500 m away, and it is best to choose a location on the windward side or upstream of the water source. When raising at home, existing conditions can also be fully utilized, using spare plots in front of and behind the house, but try as much as possible to avoid highways, railways, machine rooms, livestock pens, etc., to ensure a quiet environment. The breeding site must also be built in a place with extensive feed sources, or a place where various feeds can be purchased nearby.

The surrounding wall of the breeding site can be built with bricks and stones, or enclosed with thin iron sheets or wire mesh. The wall height should preferably be 1.2 m, because muskrats can climb along walls and escape; therefore, the inner wall should be as smooth as possible, without edges or corners. The simple shed can be built in a gable shape or a single-slope style. Generally, wood, angle steel, bamboo, etc. are used to make the frame, covered on top with asbestos tiles, felt paper or thatch, etc. The shed eaves height is 1.1-1.5 m, the width is 2 m for a single row of pens and about 4 m for a double row of pens, and the length can be determined according to breeding conditions, the number and scale of animals raised, and the size of the site. In winter, vegetable cellars or plastic greenhouse sheds can also be used for raising.

In terms of overall structure, the pen is mainly composed of three major parts: (1) Nest chamber: this is the place where muskrats rest and give birth and nurse their young. It is divided into two parts, the inner chamber and the outer chamber. The inner chamber is larger, and the outer chamber is smaller. (2) Exercise yard: this is the place where muskrats move about, eat and mate. (3) Water pool: this is the place where muskrats bathe and mate, and it must be a watertight container. Whether it is the nest chamber or the top cover of the pen, there must be wire mesh covering, and a small door or hole must be left for feeding, catching or observation, with its size based on convenience of operation.

B. Feed Preparation

The feed sources for muskrats are extremely wide, cheap and easy to obtain. Concentrate feed is mainly grain-based, such as corn flour, barley flour, soybean cake flour, wheat bran, etc.; root tuber crops include carrots, radishes, sugar beets and potatoes, etc.; melons such as pumpkins and squash; vegetables such as cabbage, Chinese cabbage, green vegetables, etc.; in addition, various fresh aquatic plants such as water chestnut grass, cattail, reeds, water barnyard grass and other wild grasses, wild vegetables, tender leaves, etc. can all be used as green feed. Of course, in captive-bred rats, a certain amount of animal-based feed (fish meal, milk powder) and yeast powder, bone meal, salt, etc. must also be supplemented to ensure the nutritional needs of each developmental stage. The principle for compounding muskrat feed should be based on full-price nutrition and diversification. Usually in spring and summer, green feed is the main component, about 300 grams per adult rat per day, with concentrate feed as a supplement of about 50 grams; during the overwintering period, food intake drops sharply, and the daily ration is mainly carrots and radishes, supplemented with vegetables and concentrate feed at about 200 grams or so, but green hay should be provided.

Concentrate feed can be made into granular, block or steamed bun form according to the ratio and fed, or prepared into a semi-dry and semi-moist form, but it must be cooked before feeding. Feeding should be done at fixed times and fixed frequencies.

II. Feeding and Management of Muskrats

A. Feeding and Management in Spring

Spring is precisely the preparation period for mating and the mating period. In southern regions, the preparation period for mating roughly begins in February, and the mating period begins in March; in northern regions, the preparation period for mating roughly begins in March, and the mating period begins in April. The management key points for each period are introduced as follows:

1) Preparation period for mating

Carry out a comprehensive inspection of the herd, check the body condition of the breeding rats, supply water to the pool early, provide enough bedding grass in the nest, increase the temperature inside the nest cage (10-12 degrees Celsius), and stimulate estrus. Check whether the nest cage contains a male-female pair. For male and female rats born the previous year that have not yet come into estrus, place a light bulb 50-60 cm away from the pool cover from 6-9 p.m. and illuminate for several hours to stimulate estrus. At the same time, provide sufficient concentrate feed and roughage for the breeding period (mainly fresh poplar and willow branches, plus supplementary vegetable feed such as cabbage and carrots), and do a good job in disease prevention. Add 1 handful of vitamin powder or malt supplement to every 100 kg of concentrate feed, continuing until the mating period.

2) Mating period

In this period, in addition to the same management as the previous period, the main measure is to place branches or green grass in the exercise yard to provide a concealed environment, and at any time supplement roughage for feeding and for making their own nests.

3) Giving birth and lactation period

In this period, in addition to supplementing and feeding concentrate feed for the breeding period, according to local conditions, soybean milk or cow's and sheep's milk should be used to mix the feed, so as to ensure normal lactation of the newborn rats and the nutrition needed by the female rats to conceive through mating. For the roughage fed, sufficient fresh and tender forage grass and branches should be provided according to the season. In addition to ensuring that they have enough fresh and tender roughage to eat, they can also carry it back into the nest to tightly block the water hole and avoid newborn rats falling into the pool due to blind crawling.

4) Growing period

When the young rats are 28-30 days after birth, they should be separated from the nest in time to facilitate the birth of the second litter and the mating and conception of the third litter. The separated young rats should be raised together in the same nest for growing out, and sufficient concentrate feed and palatable roughage should be provided. The bath water in the pool should be refilled at any time to avoid drowning of young rats because they cannot climb back home. After separation, the young rats can generally be grown out in 3 months.

B. Feeding and Management in Summer

The management techniques in summer are almost the same as in spring, but attention should be paid to hygiene and disease prevention, and disinfection of the site and tools should be done well. If disease is found, timely prevention and treatment should be carried out. Because muskrats are herbivorous animals, antibiotics should be prohibited to avoid digestive system diseases caused by intestinal flora imbalance. In summer, mating, giving birth and nursing of muskrats can proceed simultaneously. Because they are polyestrous animals, they can accept mating again within a few days after giving birth, while also nursing their young well, and may nurse more than two litters of young rats to grow out. Therefore, the site must be kept quiet, and sufficient, clean bath water must be provided.

C. Feeding and Management in Autumn

In autumn management, sufficient overwintering feed should be prepared, and overwintering hay should be stored. In addition, selection and mating of growing muskrats should be carried out, pairing males and females from different nests, and entering overwintering rearing. If nest chambers are insufficient, they can be overwintered in groups in the same nest, and selection and mating can be carried out when the preparation period for mating arrives. From late autumn to before winter, the pool water should be changed with fresh water every other day or every few days until it freezes.

D. Management in Winter

Winter management mainly consists of sufficient grass bedding for warmth, timely feeding of feed and vegetables, and persistent observation. The main methods are: fill the pool with dry grass, letting the muskrats make their own grass holes and live in an orderly manner. Feeding of feed and vegetables should persist once a day, and their activity should be observed and recorded well.