Swine First Term Coverage Management Of Replacement Gilt PDF

Swine Production Antonio J. Barroga Swine First Term Coverage MANAGEMENT OF THE REPLACEMENT GILT The feeding of the replacement gilt is similar to the fattening pigs, however at 4 months old or at a weight of 70 kg,...

Swine Production Antonio J. Barroga Swine First Term Coverage MANAGEMENT OF THE REPLACEMENT GILT The feeding of the replacement gilt is similar to the fattening pigs, however at 4 months old or at a weight of 70 kg, weakness of legs can be observed, hence, the finisher diet should be shifted to a developer diet as this contains higher level of calcium which is essential for bone development. This nutrition guid e is indispensable as replacements gilts characterized by leg weakness will not be a potential breeder aside from its reproductive performance. Moreover, the basis for selecting replacement gilt is its growth rate and body conformation. But recent research proves that its fertility status is of great help to produce more parities and heavy piglets at birth and large litter size in every parity. Effect of Boar Exposure in the Pen of the Gilt at First Estrus If the boar is brought daily to the pen of 135-day old replacement gilt, around 61% will manifest estrus in 4 weeks and this should be continued until they reach the proper age of mating to attain successful gestation. The ideal age for first mating starts at 7 months at a weight of 120- 140 kg. It is also important that the boar to be brought to the pen should be 10 months and shows signs of aggressiveness such as salivation which can also be related to high libido and fertility rate. On the other hand, if the gilt is 160 day old and there is a daily boar contact, there will be more gilt that will manifest estrus as early as the 4th week. However, 50 % of the gilts will not have successful second estrus, which is in contrast when they had boar exposure at an earlier age of 135 days. 1  Swine Production Antonio J. Barroga Feeding and Management of the Gilt upon Arrival in the Farm. The diet of the gilts from the source farm should be provided to buyers to avoid stress due to sudden shifting of the feeds in the farm of the buyer. A back fat thickness of 16-18 mm is necessary during the first mating. It is equally important too that the gilt should maintain fence line contact with the boar at least twice a day for the next 48 hours (Fig. III.1) Features of Ideal Breeder Gilt One of the features of effective breeder gilt is its ability to rear piglets in a year or known as piglets weaned per sow per year (PWSY). One of the greatest contributors for PWSY is non productive days (NPD). NPD is the period wherein the animal is neither pregnant nor lactating. To calculate NPD, the formula can be used: NPD = 365 – (L/F/Y x (LL + GL) Where L/F/Y= Litter Size LL- lactation period, day GL- gestation period The usual NPD is 60 days ranging from 60 to 85 days. If the NPD is 60 days, this means that 16 % of the sows in the farm is not productive (60/365*100). If sows can rear 21.5 piglets per year and have a farrowing index of 2.25 there is an equivalent of 0.06 pig lost in a year. This is the reason why it is essential to reduce NPD to produce more pigs. If the normal NPD is 30 days and was increased to 85 days, lost piglet will be equivalent to 1.5 piglets (0.06 x 25 days). For a 10 sow level, it will be equivalent to 15 piglets worth Php 30,000.00 if a 10 kg piglet is worth Php 2,000.00. 2  Swine Production Antonio J. Barroga Factors that contribute to NPD 1. Weaning to service interval, days 2. Entry to service interval, days 3. Service to return-to service interval, days 4. Weaning-cull-intervals, days 5. Breeding to fail-to-farrow, days 6. Breeding to cull interval, days Economic Importance of Farrowing Rate ( FR) FR % = Sows Farrowed/Sows bred x 100 The average FR in the industry is 76% ranging from 61% (10% of low performing farm) to 89% (10 percent of high performing farm). Assessing Productive Farrowing Rate in Breeder Farms Since FR is a component of FR, this is not effective in reflecting the real basis for a productive breeder farm. This is because FR does not include the bred sows that died, sows that got lamed and sick which was the result of unsuccessful pregnancy. Because of this, so that there will be an effective basis for FR as a reflection of productive breeder farm the calculation of FR can be modified to: Adjusted FR = Number of Sows Farrowed/Number of sows bred – Number of sows bred that died due sickness and lameness 3  Swine Production Antonio J. Barroga Factors that Affect Low Conception Rate, (CF) 1. Sperm Viability. Failure of sperm cell to fertilize all the egg cells that were ovulated. There are many factors that can contribute to CF in breeder farms. One of which is the boar factor, hence it is important for gilts or sows to trace the age of the boar that was used, if breeders are sick, problems of the ovary and other parts of the reproductive system, environmental condition during breeding time (28 ⁰C or below, this underscores the importance of daily bathing of breeders for farms that are not tunnel ventilated). Moreover, the diet should be high in protein and minerals and normal breeding load of boar should be maintained. Boars ranging from 12 -18 months should be used twice or thrice per week, 18-30 months at 5 to 7 times per week. It is also important that the boar should not be vacant in breeding for more than one week, because the first ejaculate will be of poor quality hence the probability of unsuccessful pregnancy will be high. There is also a contribution of the gilt and sow in CF and this is the length of lactation. This should not exceed 30 days so that they can produce more viable egg cells that will be fertilized by the sperm cells so that there will be no recurrence of estrus. Moreover, the weaning to service interval (WSI) should not be more than 7 days and that there should be no reproductive tract disorders or anatomical defects and the diet should be free from aflatoxin contamination. The manner of breeding is also important if we one has to achieve successful pregnancy. Breeding time should not be beyond 7:00 AM and in the afternoon it should start at 4:00. Avoid breeding towards noontime as it is very hot especially if the farm is not tunnel ventilated. It is also important that the semen to be inseminated should be of high quality and the volume of semen ejaculate should not be less than 150 ml and the sperm count per ml should be at least 350 million. Therefore, ejaculates should be regularly checked for sperm count and motility. There are studies which showed that regular ascorbic acid supplementation at 5 grams in the boar’s diet particularly in summer months can increase sperm count (Fig III.3). 4  Swine Production Antonio J. Barroga It is also important that during insemination the back of the sow or gilt should be pressed slightly in order that the catheter will be locked in the cervix thus allowing better penetration of the sperm cells towards the center of the uterus. A saddle or AI dummy can instead be placed also on the back to further facilitate catheter lock in (Fig III.2).A sow being artificially inseminated with an improvised saddle while applying pressure on the back can result to a FR of 85% and a CR of 98% Table 1.Tabulation for average sow parity. Parity Week 1 Week 2 Week 3 Week 4 Total Sow1 Freq2 So Freq Sow Freq Sow Freq Sow Freq w 1st 5 5 3 3 5 5 4 4 17 17 2nd 5 10 5 10 2 4 6 12 18 36 3rd 2 6 6 18 4 12 11 33 23 69 4th 2 8 0 0 4 16 3 12 9 36 5th 1 5 4 20 4 20 9 45 18 90 6th to 2 14 0 0 3 21 2 14 7 49 8th Total 17 48 18 51 22 78 35 120 92 297 Ave 2.82 2.83 3.54 3.43 3.23 1 Number of farrowed sows on the first week and first parity. 2 Average of first parity( 5 sows x 1 (Parity)= 5. 2. Parity A breeder sow will farrow piglets of high genetic value if 47 % of the total sow population is on parity 3, 4 and 5 or 57 % is on parity 3 to 6. This parity distribution at any given time will result to heavier piglets and their genetic merit will be a potential benefit for the hog farmer. Finally, in order to sustain a good gene pool of the breeders, this should be the recommended parity distribution. It is important that a breeder farm should maintain ideal average sow parity (ASP) of 3-4. Table 1 shows that the ASP of a 450 sow level is 3.23. This means that 54 % of the total sow level or a total of 50 sows against 92 farrowings are in the 3rd, 4th and 5th parity. If this ASP is maintained, quality piglets can be sustained because of younger sows and consequently, higher genetic value. To maintain a high gene pool the annual culling rate should 5  Swine Production Antonio J. Barroga be 33% and the annual replacement rate by gilts for sows should be 50% or a monthly replacement of 4.16 %. 3. Sperm Count. Even if the timing of mating is accurate if there is poor quality semen due to low sperm count, it is very difficult to effect successful fertilization of a small population of sperm of the egg cells resulting to CF. Therefore; good quality semen should have at least 350 M sperm cells/ml. 4. Sperm Motility. This is an effective parameter for successful pregnancy of breeder sows. A motility rate of more than 90 % can influence an effective fertilizing ability of the egg cells in the fallopian tube because of the speed of the sperm cell in reaching this tube hence assuring continuous and successful pregnancy. 5. Timing of Mating. Normally a breeder sow should be bred on the second day of estrus because ovulation occurs 30-40 hours after the first day of estrus. Consequently, after pure standing heat (riding the back without resistance for more than 30 seconds) a follow up is done after 6-12 hours. It is also strongly suggested that heat detection should be done twice a day. 6. Mycotoxin. Aflatoxin in the feeds can affect the potential of the sow to breed because of the symptoms of infertility and abortions. The moisture content of raw materials such as corn, rice bran, soya and fish meal should not exceed 13 % so that there will be an assurance that the feed will be aflatoxin free. Zearalenone, is a kind of mycotoxin when consumed by a gestating sow during the early stage of gestation can result to high embryonic mortality. (Fig III.4) 7. Pregnancy Failure (PF). If PF occurs at Day 35, the dead embryos maybe reabsorbed and PF may not be observed. During the first 12-14 days after fertilization of the ova, they are still floating and are of equal space in the uterus ready for implantation towards full term gestation. The implantation occurs from Day 28. Because of this it is important that a breeder farm should have a community pen wherein they will temporarily stay for heat 6  Swine Production Antonio J. Barroga detection and insemination prior to their transfer to the gestating stall (Fig III.5).In the community pen, the dry sows are inseminated or bred instead in the gestating stall. There will be higher CR here because more egg cells will be fertilized by the sperm cell because it is in the community pen wherein a reliable standing heat is demonstrated because of the meticulous and sufficient heat detection techniques are done by farm caretakers. 8. Water Intake. A gestating animal needs adequate water for normal growth of fetus. The normal water intake should be 2 and ½ times their dry matter intake. Hence, during the gestation period, the water is very important especially when farrowing approaches due to the large fetus. 9. Nutritive Value of Feed. A deficiency in the diet of the gestating sow can affect her body condition and the growth of the fetus. Therefore, no deprivation of a balance diet should be done to avoid problems during farrowing. Fence line contact between boar and sows in estrus. 7  Swine Production Antonio J. Barroga A sow with an improvised saddle or AI dummy Effect of ascorbic acid supplementation on the sperm count of boar ejaculate. 8  Swine Production Antonio J. Barroga A zearalenone contaminated corn 9  Swine Production Antonio J. Barroga A community pen for dry sows 10  Swine Production Antonio J. Barroga 11