The main measures to improve the fecundity of black dolphin

(1) to formulate a reasonable breeding plan

Half-frequency breeding or frequent breeding can improve the fecundity of black dolphins. However, according to the actual situation and the level of feeding and management in our country, the traditional breeding method should be adopted, that is, after weaning, the weaning time should be 15-20 days, and about 4 babies should be reproduced every year. In terms of timing, it is mainly in early spring and autumn to seize the time to breed and create conditions for winter reproduction.

(2) strict selection of species

When choosing to breed dolphins, they are required to be healthy, physically strong and sexually active. It should also be selected according to pedigree, reproduction, production performance records and so on. The testes of male dolphins are required to be large and symmetrical, and cryptorchidism and single-testicular males are not allowed to remain. Female dolphins require strong testicular fecundity and good motherhood. The vulva is upright, the nipple is big, a pair should be normal, timely eliminate the female dolphin with few offspring, low conception rate and poor lactation.

(3) Scientific breeding

Keeping the breeding condition of dolphin is one of the important measures to improve the fecundity of black dolphin. Before the arrival of the breeding season, the amount of protein feed, minerals and vitamins should be gradually increased. For over-fat breeding dolphins, the feeding amount of high-energy feed should be properly limited, while all too thin breeding dolphins should be strengthened to maintain their physical condition so as to make them have exuberant sexual function.

(4) reasonable age structure

Among the breeding dolphins, the young, strong and old breed dolphins should have a reasonable age structure. Dolphin breeds are generally used for about 2 mi-5 years, and about 1 / 3 or 3 of dolphins are selected to be eliminated every year. Therefore, more than 1 / 3 of reserve dolphins should be selected every year, and further selected as the source of dolphin breeding. The whole flock of dolphins should be mainly young and middle-aged, and the proportion of old breeds is too large, which will affect the aquatic products of the whole herd.

(5)

Avoid inbreeding

In dolphin production, keep in mind that inbreeding can easily lead to stillbirth and deformed piglets, which can also cause infertility or decrease the vitality of offspring. In a dolphin breeding farm or production farm, it is necessary to establish a dolphin breeding file system, breeding records and pedigree data, which is an important basis for consanguinity selection and prevention of inbreeding. Even if they are professional dolphin farmers, they should also know the blood relationship of their own dolphin breeds.

(6) timely breeding

1. The female dolphin is easy to conceive by mating (blood mating) within 1mi-19:00 after giving birth. However, the female dolphin is required to have a strong physique and a high level of feeding and management, so it is not suitable for continuous use.

two。 After weaning, female dolphins are often easily conceived when they are mated within 2 days of 1 Murray.

3. After the end of false pregnancy, estrus mating is also easy to conceive.

In short, the fecundity of black dolphins is affected by many factors. In order to improve the fecundity of black dolphins, comprehensive measures must be taken to be effective.