Methods for Establishing a Reasonable Parity Structure in the Sow Herd
Establish a reasonable parity structure in the sow herd
(Agricultural Wealth Network) The ideal parity structure of a sow herd is: first-parity sows account for 20%; second parity 18%; third parity 17%; fourth parity 15%; fifth parity 14%; sixth parity 10%; seventh parity and above 6%.
Early pregnancy testing, to find open sows as early as possible, stimulate them to come into estrus, and rebreed them promptly using a pregnancy diagnosis device. After sows are mated, a B-ultrasound detector should be used for early determination of whether they are pregnant, so that non-pregnant sows can be identified and rebreed in time. This is an effective measure for increasing the reproductive rate of the sow herd and reducing the loss of feeding costs caused by open sows. Testing is generally carried out 25 days to 30 days after mating.
Carefully check estrus and return to estrus. First is estrus: whether natural mating or artificial insemination is used, timely mating is an important factor in obtaining good reproductive performance, and accurate estrus detection is the prerequisite for timely mating. Second, promptly identify sows returning to estrus. If there is no pregnancy diagnosis device on the farm, then return-to-estrus sows can only be identified by manual estrus checks. Therefore, at about 18 days to 24 days, 39 days to 45 days, and 60 days to 66 days after mating, checks for return to estrus should be strengthened.
Use mature boars for estrus detection, twice a day, once 30 minutes after the morning feeding and once before getting off work in the afternoon.
An ideal estrus-detection boar should be at least over 12 months of age, walk slowly, and have abundant foam in the mouth. When driving the boar, use a pig-driving board or another person to limit the boar's walking speed.
Driving the boar into the sow pen provides the best stimulation for the sows. By sniffing the sows, the boar can, on the one hand, stimulate the sows to come into estrus, and on the other hand, help identify sows returning to estrus. Boars and sows should be brought into contact 2 times a day, 20 minutes each time. When the boar is driven in front of the sows, the worker should carefully observe the sows' reactions from behind. Back-pressure checking can be used, and the flank and abdomen can also be stimulated. The average estrous cycle of sows is 21 days (18 days to 23 days), and the duration of estrus is 2 days to 3 days. A sexual cycle is roughly divided into 4 stages: proestrus, estrus, metestrus, and diestrus. The key to successful mating is correctly grasping the signs of estrus and mating at the right time. Proestrus signs in sows: vulva cherry-red and swollen, biting bars, restlessness, reduced appetite, mounting, mucus flowing from the vulva, being mounted by penmates, but no standing reflex; estrus signs in sows: reduced vulvar swelling and redness, thick sticky mucus, arched back, staring gaze, erect ears, standing reflex, with the standing reflex being obvious when a boar is present; standing still when mounting other sows or being mounted, reduced appetite, emitting a distinctive grunting sound, willingness to accept the keeper, and allowing the boar to mate. All or some of the signs may be observed during estrus, but there will be differences between lines. The shorter the weaning-to-mating interval, the longer the duration of estrus and the more obvious the signs of estrus. In group housing, estrous sows will mount other sows or allow other sows to mount them. When fed in gestation stalls, some estrous sows will stand while others will lie down, so normal estrus signs cannot be observed, and the keeper therefore needs to check estrus with the help of head-to-head contact with a boar.
Reduce non-productive days. Sow non-productive days: that is, the number of days in a year that sows in the breeding herd are in neither the pregnant nor the lactating period. US data show that the best pig farms can achieve 30 days to 35 days of non-productive days, relatively good farms can achieve 40 days to 45 days, the average level is around 70 days, and many herds exceed 70 days. Then, if calculated on the basis of a gestation period of 114 days and a lactation period of 21 days, farms with 30 days to 35 days of non-productive days have an average annual production of 2.48 litters to 2.44 litters per sow; farms with 40 days to 45 days of non-productive days have an average annual production of 2.41 litters to 2.37 litters per sow; farms with 70 days of non-productive days have an average annual production of 2.19 litters per sow. We use the following example to illustrate the impact of non-productive days on farm profitability. Suppose two farms (Farm A and Farm B) each have 500 adult sows, Farm A has 40 non-productive days, and Farm B has 70 non-productive days. Both farms A and B have gestation and lactation periods of 114 days and 21 days respectively, so the average annual number of litters per sow on Farms A and B is 2.41 and 2.19 respectively. If 9.5 pigs are weaned per litter, then the difference in output is (2.41 - 2.19) litters x 9.5 pigs x 500 sows = 1045 weaned pigs. Assuming that when these pigs are marketed the feed and medication cost per pig is 1000 yuan, the market price of live pigs is 12 yuan per kg, and the mortality rate of medium and large pigs is 10%, then the difference in profit between Farms A and B is 1045 pigs x 90% x 100 kg x 12 yuan - 1045 pigs x 90% x 800 yuan = 376200 yuan. And the difference in non-productive days between the two farms is 15000 days, equivalent to Farm B raising 41 more sows that produce no benefit at all compared with Farm A. If this item is calculated, then the difference in profit between the two farms is even higher!
Timely and proactive culling. For a pig farm with normal turnover, the annual breeding stock replacement rate is about 30% to 40%. Therefore, sows with too high a parity, declining performance, long periods without estrus, inflammation of the reproductive organs, or poor legs and feet should be proactively culled. Once a sow is determined to be culled, it should be culled immediately. Some pig farms are unwilling to cull sows when the price of live pigs is high, but this is actually unscientific.
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Early pregnancy testing, to find open sows as early as possible, stimulate them to come into estrus, and rebreed them promptly using a pregnancy diagnosis device. After sows are mated, a B-ultrasound detector should be used for early determination of whether they are pregnant, so that non-pregnant sows can be identified and rebreed in time. This is an effective measure for increasing the reproductive rate of the sow herd and reducing the loss of feeding costs caused by open sows. Testing is generally carried out 25 days to 30 days after mating.
Carefully check estrus and return to estrus. First is estrus: whether natural mating or artificial insemination is used, timely mating is an important factor in obtaining good reproductive performance, and accurate estrus detection is the prerequisite for timely mating. Second, promptly identify sows returning to estrus. If there is no pregnancy diagnosis device on the farm, then return-to-estrus sows can only be identified by manual estrus checks. Therefore, at about 18 days to 24 days, 39 days to 45 days, and 60 days to 66 days after mating, checks for return to estrus should be strengthened.
Use mature boars for estrus detection, twice a day, once 30 minutes after the morning feeding and once before getting off work in the afternoon.
An ideal estrus-detection boar should be at least over 12 months of age, walk slowly, and have abundant foam in the mouth. When driving the boar, use a pig-driving board or another person to limit the boar's walking speed.
Driving the boar into the sow pen provides the best stimulation for the sows. By sniffing the sows, the boar can, on the one hand, stimulate the sows to come into estrus, and on the other hand, help identify sows returning to estrus. Boars and sows should be brought into contact 2 times a day, 20 minutes each time. When the boar is driven in front of the sows, the worker should carefully observe the sows' reactions from behind. Back-pressure checking can be used, and the flank and abdomen can also be stimulated. The average estrous cycle of sows is 21 days (18 days to 23 days), and the duration of estrus is 2 days to 3 days. A sexual cycle is roughly divided into 4 stages: proestrus, estrus, metestrus, and diestrus. The key to successful mating is correctly grasping the signs of estrus and mating at the right time. Proestrus signs in sows: vulva cherry-red and swollen, biting bars, restlessness, reduced appetite, mounting, mucus flowing from the vulva, being mounted by penmates, but no standing reflex; estrus signs in sows: reduced vulvar swelling and redness, thick sticky mucus, arched back, staring gaze, erect ears, standing reflex, with the standing reflex being obvious when a boar is present; standing still when mounting other sows or being mounted, reduced appetite, emitting a distinctive grunting sound, willingness to accept the keeper, and allowing the boar to mate. All or some of the signs may be observed during estrus, but there will be differences between lines. The shorter the weaning-to-mating interval, the longer the duration of estrus and the more obvious the signs of estrus. In group housing, estrous sows will mount other sows or allow other sows to mount them. When fed in gestation stalls, some estrous sows will stand while others will lie down, so normal estrus signs cannot be observed, and the keeper therefore needs to check estrus with the help of head-to-head contact with a boar.
Reduce non-productive days. Sow non-productive days: that is, the number of days in a year that sows in the breeding herd are in neither the pregnant nor the lactating period. US data show that the best pig farms can achieve 30 days to 35 days of non-productive days, relatively good farms can achieve 40 days to 45 days, the average level is around 70 days, and many herds exceed 70 days. Then, if calculated on the basis of a gestation period of 114 days and a lactation period of 21 days, farms with 30 days to 35 days of non-productive days have an average annual production of 2.48 litters to 2.44 litters per sow; farms with 40 days to 45 days of non-productive days have an average annual production of 2.41 litters to 2.37 litters per sow; farms with 70 days of non-productive days have an average annual production of 2.19 litters per sow. We use the following example to illustrate the impact of non-productive days on farm profitability. Suppose two farms (Farm A and Farm B) each have 500 adult sows, Farm A has 40 non-productive days, and Farm B has 70 non-productive days. Both farms A and B have gestation and lactation periods of 114 days and 21 days respectively, so the average annual number of litters per sow on Farms A and B is 2.41 and 2.19 respectively. If 9.5 pigs are weaned per litter, then the difference in output is (2.41 - 2.19) litters x 9.5 pigs x 500 sows = 1045 weaned pigs. Assuming that when these pigs are marketed the feed and medication cost per pig is 1000 yuan, the market price of live pigs is 12 yuan per kg, and the mortality rate of medium and large pigs is 10%, then the difference in profit between Farms A and B is 1045 pigs x 90% x 100 kg x 12 yuan - 1045 pigs x 90% x 800 yuan = 376200 yuan. And the difference in non-productive days between the two farms is 15000 days, equivalent to Farm B raising 41 more sows that produce no benefit at all compared with Farm A. If this item is calculated, then the difference in profit between the two farms is even higher!
Timely and proactive culling. For a pig farm with normal turnover, the annual breeding stock replacement rate is about 30% to 40%. Therefore, sows with too high a parity, declining performance, long periods without estrus, inflammation of the reproductive organs, or poor legs and feet should be proactively culled. Once a sow is determined to be culled, it should be culled immediately. Some pig farms are unwilling to cull sows when the price of live pigs is high, but this is actually unscientific.
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