How many litters of lambs do small-tailed Han sheep produce in a year?

Small-tailed Han sheep can breed all the year round, and their fecundity is extremely strong. They give three births in two years, and many give birth twice a year. According to the statistics of 2101 births from 1964 to 1991, the small-tailed Han sheep is a prolific breed, with an average lambing rate of 281.9% and a maximum of 9 lambs per litter.

Reproductive performance characteristics of small-tailed Han Sheep

In the first four births of ①, the lambing rate increased greatly with the increase of parity.

The third and fourth lamb rates of the third and fourth births of ② are about twice as high as those of the first and second births, accounting for more than 40% of the number of ewes delivered.

Sexual maturity of small-tailed Han Sheep

The average proestrus of small-tailed Han sheep is 186-255 days, and there is a great difference in sexual maturity. the main reason is that sexual maturity is affected by birth season, number of lambs, birth weight and growth. The weight of a 6-month-old ewe is 60% of that of an one-year-old sheep, but its uterus weighs more than 76% of its one-year-old uterus. Thus it can be seen that the early maturity of reproductive organs is an important germplasm characteristic of high fecundity varieties. The ram of Han sheep with small tail matures at the age of 5 months. The young ram has sexual desire and climbing behavior at the age of 4 months, and the penis is aroused at the age of 5 months. 85% of the mature sperm were found in the vas deferens at the age of 5 months and 100% at the age of 6 months. At this time, the sperm density in the original semen was 3 billion / ml, which basically reached the standard of insemination. However, the stage body maturity has not yet been completed, so it is not suitable to participate in mating. A small amount of mating can be used in 8-month-old rams, but it is necessary to strengthen breeding. In general, it is best for 1-year-old rams to participate in mating on the premise that their nutritional needs are met.

Estrus of small-tailed Han sheep

Small-tailed Han sheep are in estrus all the year round, but the estrus cycle is 17.2 ±2.17 days, the duration of estrus is 2.66 ±1.15 days, and the duration of first estrus is the shortest in spring and autumn. This is related to age and nutritional status. In well-nourished adult ewes, the estrous cycle is short, the days of postpartum estrus is 71.88 ±23.78 days, the first fetus is the longest and the fourth fetus is the shortest.

The pregnancy period of small tail Han Sheep

The gestation period of small tail Han sheep was 148.6 ±1.93. there was no significant difference among different parity and lambing types. Due to the difference of age and nutritional status, there were some differences, but the difference was not significant.

Non-seasonal reproductive characteristics of small-tailed Han sheep

Non-seasonal reproduction is a prominent feature of small-tailed Han sheep. According to the statistics of 170 ewes, 45 ewes were delivered from January to March, accounting for 26.47%, 61 ewes were delivered from April to June, accounting for 35.58%, 23 ewes were delivered from July to September, accounting for 13.53%, and 41 ewes were delivered from October to December, accounting for 24.12%.