ABSTRACT
Crossbred female swine (n = 393) were used in a multiparity study at five experiment stations to evaluate the effects of dietary supplementation of folic acid (FA) on serum folates status and reproductive performance. The dietary treatments were a corn-soybean meal basal diet (calculated FA, .34 ppm) supplemented with 0, 1, 2, or 4 ppm FA. Experimental diets were fed continuously from a minimum of 21 d before first mating throughout the entire study. At one station, blood samples for radioimmunoassay determination of serum folates concentration were collected by vena cava puncture at mating, d 55 of gestation, d 110 of gestation, and at weaning. Stage of reproduction and dietary FA supplementation affected (P < .005) serum folates concentrations. Serum folates declined from mating to d 55, remained low at d 110, and returned to higher levels at weaning. Linear increases (P < .001) in serum folates with increasing level of dietary FA were observed at each reproductive stage. Over the course of the study, reproductive performance criteria including total pigs born, live pigs at birth and d 21, and individual pig and litter weight at birth and d 21 were not affected (P > .10) by inclusion of FA in the diet. The number of days postweaning to estrus also was not affected by FA treatment. Under the conditions of this experiment, increasing level of FA in the diet had a pronounced effect in attenuating decreased serum folates concentration during gestation but was without benefit to reproductive performance.
Subject(s)
Folic Acid/pharmacology , Lactation/drug effects , Pregnancy, Animal/drug effects , Swine/physiology , Animal Feed , Animals , Birth Weight , Female , Folic Acid/administration & dosage , Folic Acid/blood , Food, Fortified , Lactation/physiology , Litter Size , Parity , Pregnancy , Pregnancy, Animal/physiology , Random Allocation , Weight Gain , Weight LossABSTRACT
A cooperative experiment involving 999 litters was conducted at seven stations to assess the reproductive performance of gilts and sows fed different levels of energy during gestation and lactation (21 d) for three consecutive parities. Treatments consisted of two gestation (G) and two lactation (L) diets in a 2 x 2 factorial arrangement. Gestation treatments were diets fed to provide normal (5.9 Mcal/d, NG) or high (7.4 Mcal/d, HG) energy intake; lactation treatments were diets that contained 0 (NL) or 9% added fat (HL). Sows were provided ad libitum access to feed during the lactation period. Feeding the higher energy level during gestation increased pig birth weight (P < .01) and pig weight gain to weaning (P < .01). Sows that had been fed the higher level of energy during gestation (HG) ate less feed during lactation (P < .01) and lost more weight during lactation (P < .01). Increasing lactation energy intake by adding fat resulted in greater pig weight gains to 21 d of age (P < .01). Sows fed the HG-NL combination had fewer pigs on d 21 than all other treatment groups (G x L; P < .01). There was a G x L x parity interaction (P < .05) for days to estrus after weaning. Sows on the NG-HL or HG-NL treatments had increased days to estrus in Parity 1 (P < .05), whereas those on the NG-NL treatments had increased days to estrus in Parities 2 and 3 (P < .05). The HG-HL treatment minimized days to postweaning estrus during the three-parity study.(ABSTRACT TRUNCATED AT 250 WORDS)
Subject(s)
Energy Intake , Lactation/physiology , Pregnancy, Animal/physiology , Reproduction , Swine/physiology , Animal Feed , Animals , Animals, Newborn/growth & development , Animals, Suckling/growth & development , Birth Weight , Eating , Estrus/physiology , Female , Litter Size , Parity , Pregnancy , Seasons , Temperature , Weaning , Weight GainABSTRACT
Two experiments involving 1,020 litters were conducted at eight research stations to determine the effects of dietary NaCl (salt) concentration during gestation and lactation on reproductive performance of sows. Primiparous and multiparous sows were fed fortified corn- or grain sorghum-soybean meal diets at 1.82 kg/d during gestation. During the winter months (December, January, February) the feeding level was increased to 2.27 kg/d. Sows had ad libitum access to diets during lactation. Dietary concentrations of added salt were .50 and .25% in Exp. 1 and .25 and .125% in Exp. 2. When more feed was fed during gestation, the salt concentrations were reduced to .40, .20, .20 and .10%, respectively, in order to maintain a constant daily intake of Na and Cl during gestation. Gestation weight gain and lactation (21-d) weight loss of the sows were not affected by dietary salt level in either experiment. In Exp. 1, lowering the salt concentration did not influence the number of pigs farrowed, but it resulted in a .05 kg/pig reduction (P less than .01) in average birth weight. Average 21-d pig weights also tended (P less than .19) to be lower in the low-salt group. There was a decrease in litter size from the first to the second farrowing for sows fed low salt, but not for sows fed the higher salt concentration. In Exp. 2, reducing the salt content from .25 to .125% did not alter reproductive performance. The overall ratio of males to females at birth in the population of greater than 10(4) pigs was 52.3:47.7. Lower salt intakes tended to reduce the percentage of males born in both experiments, although the differences were not significant (P greater than .3). The results indicate that reducing the salt concentration in sows diets from .50 to .25 or .125% reduces birth weight in newborn pigs. When continued for more than one reproductive cycle, feeding less than .5% salt appears to reduce litter size at birth and weaning.
Subject(s)
Lactation/drug effects , Pregnancy, Animal/drug effects , Sodium, Dietary/pharmacology , Swine/physiology , Animals , Birth Weight/drug effects , Estrus/drug effects , Female , Litter Size/drug effects , Male , Pregnancy , Sodium, Dietary/administration & dosageABSTRACT
A cooperative regional study (S-145) involving 586 farrowings was conducted at five state experiment stations (Georgia, Mississippi, South Carolina, Tennessee and Virginia) to determine the influence of feeding elevated Ca and P levels during growth and development on general reproductive efficiency and longevity of confined, housed females kept for three consecutive parities. Two dietary Ca and P levels (100 vs 150% of 1979 NRC-recommended amounts) were fed ad libitum from weaning to 100 kg. A diet containing .8% Ca and .6% P was limit-fed to all gilts and to all sows during gestation and lactation. Growth rate and feed efficiency from weaning to 100 kg were similar (P greater than .10) for gilts fed 100 vs 150% Ca and P levels. A similar total number of litters (292 vs 294) was farrowed by each previous treatment group. From the previously-fed-100% Ca and P group, 78 and 65% of the sows that completed the first parity completed the second and third farrowing, respectively. Similarly, from the previously-fed-150% Ca and P group, 81 and 57% completed the second and third farrowing, respectively. Across all locations, total pigs born, live pigs born, stillborns, birth weight, number and weight of pigs at 21 d of age, sow weight at 110 d of gestation and at weaning did not differ (P greater than .10) between the two previously fed sow groups. There were significant location and farrowing effects, but most two-way interactions with Ca and P levels were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)
Subject(s)
Calcium, Dietary/pharmacology , Phosphorus/pharmacology , Pregnancy, Animal/drug effects , Swine/physiology , Animals , Body Weight/drug effects , Calcium, Dietary/administration & dosage , Female , Phosphorus/administration & dosage , PregnancyABSTRACT
Serum enzyme concentrations were determined in 319 Hampshire pigs (approx 2 months of age). Significant positive correlations were found when creatine kinase (CK) concentrations were compared with lactate dehydrogenase and malate dehydrogenase values, but not when compared with aspartate aminotransferase or alanine aminotransferase values. In an additional study, a litter from a sow with high serum CK concentrations was observed at 2, 3, 4, and 5 months of age for serum CK concentrations. The CK concentration increased as the pigs aged, and soft exudative pork was found upon slaughter of the pigs at 5 months of age. It is believed that CK, lactate dehydrogenase, and malate dehydrogenase determinations in weanling pigs would have value for reducing the frequency of the porcine stress syndrome and soft exudative pork in breeding stock. If only a portion of the genetic carriers was removed, the effect would be considerable within a few generations.
