Methods of administering vitamin A and lactic acid to gilts

A feeding method for gilts in batch farrowing, comprising:

• feeding gilts with vitamin A combined with lactic acid from an age of 140 days until estrus synchronization treatment is performed, a total of the vitamin A ranging from 5,000 IU to 50,000 IU per day, and a total of the lactic acid ranging from 0.3 g to 5 g per day, wherein the gilts are fed in a small group for 10 days, and then transferred to breeding unit pens and fed till an age of 209 d, a daily ration for gilts fed in the small group contains vitamin A at a concentration of 1,700 IU/kg, and a daily ration for gilts fed in breeding unit pens is 4700 IU/kg, the gilts housed in the small group are fed ad libitum, and an average daily feed intake of still-housed gilts is 2.2 kg;
• feeding, from an age of 210 days, the pubertal gilts with altrenogest for 18 consecutive days to achieve estrus synchronization, wherein the altrenogest is fed by 20 mg per day;
• performing, from the second day following the end of altrenogest, an estrous detection on the gilts every day;
• performing, subsequent to the appearance of estrus signs, first insemination at an interval of 8 hours to 16 hours;
• and
• performing second insemination at an interval of 24 hours later.

A method for promoting puberty onset of gilts, comprising:

• feeding, prior to puberty onset, the gilts with vitamin A combined with lactic acid;
• and
• performing, subsequent to the puberty onset, estrus synchronization treatment and insemination treatment on the gilts,
• wherein:
• for each gilt, a feeding amount of the vitamin A ranges from 5,000 IU to 50,000 IU per day, and a feeding amount of the lactic acid ranges from 0.3 g to 5 g per day;
• and
• the vitamin A combined with lactic acid is provided in the form of a mixture containing the vitamin A, the lactic acid and oil.

A method for alleviating estrus disorder of gilts, comprising:

• feeding, prior to puberty onset, the gilts with vitamin A combined with lactic acid;
• and
• performing, subsequent to the puberty onset, estrus synchronization treatment and insemination treatment on the gilts,
• wherein:
• for each gilt, a feeding amount of the vitamin A ranges from 5,000 IU to 50,000 IU per day, and a feeding amount of the lactic acid ranges from 0.3 g to 5 g per day;
• and
• the vitamin A combined with lactic acid is provided in the form of a mixture containing the vitamin A, the lactic acid and oil.