Influence of folic acid supplements on the carry-over of folates from the sow to the piglet

This experiment aimed to investigate the influence of folic acid supplements on the carry-over of folates from the sow to the fetus during late gestation and to the suckling piglet. Two groups of sixteen German Landrace sows received, during gestation and lactation, a diet supplemented with either 0 or 10 mg folic acid/kg. Increased folic acid concentrations in the serum of sows were detected only at the end of gestation (day 100) and at the end of lactation (day 28). The supplementation with folic acid to the sows' diet improved the folic acid supply of the fetus compared with unsupplemented controls; values were respectively 92.6 v. 56.2 nmol folates/l serum in newborn piglets and 171.9 v. 76.3 micromol folates/g fresh liver in stillborn piglets (P < 0.05). Folate concentrations in colostrum and milk (day 28) were 3.6- and 5.0-times higher in supplemented than unsupplemented sows. This treatment effect was also reflected in the serum of piglets until weaning. Therefore, the folic acid supply for the suckling piglet is dependent mainly upon the carry-over of maternal folates via colostrum and milk.

Effects of long-term parenteral administration of vitamin B6 on B6 status and some aspects of the glucose and protein metabolism of early-weaned piglets

The present experiment aimed to determine the effect of feeding level and parenteral supplements of vitamin B6 (pyridoxine) on B6 status as well as on glucose, C-peptide, insulin, alpha-amino-N and urea after a gastric bolus of glucose in weaned piglets; the plasma tryptophan, xanthurenic acid and kynurenine responses to a gastric bolus of tryptophan were also measured. Forty-two piglets weaned at 2 weeks of age were distributed in seven blocks of six animals each. Within each block, the animals were assigned to the following factorial treatments: two levels of feeding (28 (F28) and 56 (F56) g/kg(0.75) per d) administered by gastric-tube feeding and three levels of parenteral (intramuscular injections) vitamin B6 (0 (B60), 15 (B615) and 30 (B630) mg/d). In B60 piglets, a decrease of 30 % and 20 % in erythrocyte and plasma pyridoxal-5-phosphate respectively, were observed during the 2 weeks post-weaning. In supplemented piglets, the erythrocyte pyridoxal-5-phosphate was maximised in B615 piglets at a level 3-4 times higher than in B60 piglets (P < 0.003). However, in plasma the maximal pyridoxal-5-phosphate concentration was reached in F28-B630 piglets (P < 0.058). The glucose and insulin responses to a gastric bolus of glucose were lower, and the post-bolus decrease of glucose was slower, in F28 than in F56 piglets (P < 0.0001). The insulin:C-peptide ratio was 25 % greater in B615 piglets (P < 0.082). After the bolus of glucose, the aminoacidaemia decreased differentially according to treatments (P < 0.047), while the uraemia was at least 2-fold higher (P < 0.001) in F28 piglets than in F56 piglets and tended to be maximised in B630 piglets (P < 0.074). The response of plasma tryptophan to the gastric bolus of tryptophan was 11 % lower in B630 piglets (P < 0.057). The plasma concentration of kynurenine increased continuously during the post-bolus period and this response was more marked in F56 (P < 0.002) and in B630 piglets (P < 0.02). Xanthurenic acid was undetectable in any of the treatments. The measurements on pyridoxine status suggest that the present basal dietary level of B6 (7.7 mg/kg) was not sufficient to cover the metabolic needs. For many criteria, an optimal level was reached at 15 mg/d parenteral B6 but the response of urea to glucose bolus suggests that 30 mg/d was detrimental. Further studies are necessary to determine the dietary level of B6 equivalent to the present optimal parenteral supplements and its eventual effects on B6 status and post-weaning growth performance of piglets.

High chromium yeast supplementation improves glucose tolerance in pigs by decreasing hepatic extraction of insulin

Twenty Landrace x Yorkshire cross pigs (body wt, 47.9+/-2.9 kg) were used to evaluate effects of dietary high chromium (Cr) yeast supplementation on plasma kinetics of glucose, insulin and C-peptide. Pigs were provided free access to either a control diet (C) containing 204 microg Cr/kg or a diet supplemented with an additional 200 microg Cr/kg as high Cr yeast (CR) for between 23 and 30 d. After overnight food deprivation, dextrose (500 g/L) was infused through a jugular vein catheter at a dose of 0.5 g glucose/kg body weight with an infusion rate of 10 g glucose/min within 6 min. High Cr yeast supplementation did not affect body weight gain or food intake. There were no differences in fasting plasma concentrations of either glucose or C-peptide, although basal plasma concentration of insulin tended to be higher in pigs fed CR (P<0.10). Plasma glucose concentrations were lower (P<0.01) at postinfusion times 5, 10, 15 and 20 min in pigs fed CR. Plasma insulin concentrations in pigs fed CR were higher (P<0.05) at 2 and 0 min before the completion of dextrose infusion. However, the increase in plasma insulin concentrations was not accompanied by a comparable elevation in plasma C-peptide concentrations. The 30-min (postinfusion) area of plasma glucose concentrations tended to be lower (P<0.10) in pigs fed CR, but there were no differences in 30-min areas of either plasma insulin or plasma C-peptide concentrations between treatments. Plasma clearance rates of glucose, insulin and C-peptide were higher and their half-lives shorter (P<0.05) in pigs fed CR. In conclusion, dietary high Cr yeast supplementation improved glucose tolerance, possibly through a decrease in hepatic extraction of insulin.

A rapid and non-surgical procedure for jugular catheterization of pigs

A rapid and non-surgical method for jugular catheterization in pigs was set up in 30 piglets of 6.2 kg, 23 pigs of 46 kg and 84 kg and two lactating multiparous sows. The animal was restrained on a V-shaped table (piglets) or with a rope around the mandible (slaughter pigs and sows). The vein was located with the Vacutainer system and a wire guide was inserted into the Vacutainer needle up to the vein lumen. When the needle was removed, the catheter was inserted over the wire guide and advanced until it penetrated the skin and thereafter, the vein wall. The catheter was fixed outside by a large tape and coiled inside a patch just behind the ears. The technique utilizes readily available material and is no more risky for the animal than a single blood sampling. Moreover, it can be performed within 15 to 20 min (including animal restraint) within pens. This new approach might have important implications not only for research purposes by facilitating repeated blood samplings but also for projects which require a rapid and easy method for testing of any kind of pharmaceutical or other type of products under husbandry conditions.

An estimation of the requirement for folic acid in gestating sows: the metabolic utilization of folates as a criterion of measurement

Sows at their second parity were randomly distributed in five groups of seven animals each to determine the dietary concentration of folic acid that optimizes the metabolic utilization of the vitamin during gestation. The groups differed by dietary supplement of folic acid: 0, 5, 10, 15, or 20 ppm. Sows were fed 2.5 kg of diet each day. The response of serum folates and folate binding capacity to treatments and the excretion of urinary folates after an i.v. injection of folic acid were measured. The total daily excretion of urinary folates was corrected according to the response to one i.v. injection of saline on the day preceding the i.v. injection of folic acid. The decrease of total serum folates throughout gestation was less pronounced in the groups fed 15 and 20 ppm of dietary folic acid (supplement x period interaction, P<.06) than it was in the other three treatments. The proportion of i.v. folic acid not recovered in sow urine (injected - excreted) decreased as the amount of dietary folic acid increased to reach a minimum, which differed according to the period (supplement x period interaction, P<.02); it was 15 ppm during wk 1 of gestation and 10 ppm for the other periods studied. The unrecovered folates increased over a dietary concentration of 15 ppm. These minimum values correspond to the most appropriate feed concentration that covered the whole body utilization (tissue and cell metabolism, catabolism, and storage) of folates by the sows and could be interpreted as a reliable index of the requirement.

Dietary supplements of folic acid during lactation: effects on the performance of dairy cows

The present experiment was undertaken to determine the effects of dietary supplements of folic acid administered from 4 wk prepartum to 305 d of lactation on lactational performance. Sixty-three Holstein cows were assigned to 22 blocks of 3 cows according to lactation number, milk production, and body weight (BW). Within each block, cows received 0, 2, or 4 mg of folic acid/kg of BW per d. Dietary supplements of folic acid increased serum and milk folates but affected milk production and composition of primiparous and multiparous cows differently. Supplementary folic acid had little effect on milk production and composition of primiparous cows, except that milk production decreased during the first 100 d of lactation. However, during a complete lactation (3 to 305 d after calving), supplementary folic acid was associated with increased milk production by multiparous cows (8284 +/- 560, 8548 +/- 380, and 8953 +/- 191 kg for cows fed diets supplemented with 0, 2, and 4 mg of folic acid/kg of BW per d, respectively). The percentage of ash in milk was decreased for cows fed the highest amount of dietary folic acid. During the first 100 d of lactation, supplementary folic acid was associated with a lower concentration of nonprotein nitrogen in the milk of multiparous cows. The present study confirms results obtained previously, suggesting that, although the supply of folates from an unsupplemented diet and the ruminal microflora is sufficient to avoid a deficiency in folic acid, supplementary folic acid may increase the milk production of cows in the second lactation or greater.

Sensitivity of reproducing sows and suckling pigs to stray voltage

OBJECTIVE

To evaluate whether stray voltage reduces welfare of sows and their litters, causes reproductive problems, or impairs growth and survival of suckling pigs.

ANIMALS

120 gilts assigned randomly to 3 treatment groups: 2-V baseline plus 3-V pulses (2-5 V); 5-V baseline plus 3-V pulses (5-8 V); and control treatment (0-0 V).

PROCEDURE

Behavior was recorded during gestation and lactation. Water and feed intakes were measured daily, milk composition was evaluated once during lactation, and hematocrit, hemoglobin, glucose, total protein, aspartate transaminase, alanine transaminase, albumin, globulins, and fatty acids values were measured at mating, weeks 8 and 15 of gestation, parturition, and weaning. Prolific ability of sows, mortality and disease of suckling pigs, and growth rate until 56 days of age were recorded.

RESULTS

Gilts under voltage were lying down more often and performing less abnormal behaviors than were control gilts. Behavior of sows and suckling pigs was not affected by treatments. Water and feed intakes were similar among treatments, except during week 1 of lactation where feed intake was lower in the control group. Fecundity and prolific ability of sows, percentage of stillbirth, growth rate of suckling pigs, and milk composition were similar among treatments. More suckling pigs died in 2-5-V group than in other groups, but diarrhea was more frequent in the control group. Blood metabolites were similar among treatment groups.

CONCLUSIONS

Transient stray voltage at values up to 8 V did not impair the welfare, reproductive performance, or health of sows and suckling pigs.

Serum concentrations of micronutrients, packed cell volume, and blood hemoglobin during the first two gestations and lactations of sows

The objective of the present work was to describe the changes in serum concentrations of some micronutrients during the first 2 gestations and lactations of 33 gilts in order to establish blood reference values for a rapid assessment of nutritional status. In both parities, blood samples were taken from the jugular vein at mating, 5, 10 and 15 wk of gestation and l d and 4 wk after parturition (weaning). Reference values (mean, standard deviation, minimum, maximum) for serum folates, vitamin B12, vitamin B6 metabolites (pyridoxal and pyridoxal-5-phosphate), calcium, phosphorus, sodium, zinc, copper and iron, as well as blood hemoglobin and packed cell volume are reported for each studied time. Differences between parities and between each time are also reported. Results from the present report demonstrate that knowledge of the physiological state of the sows is critical for the assessment of nutritional status of an individual or a breeding herd by interpretation of analyses of blood constituents.

Serum and milk folates during the first two gestations and lactations in Romanov, Finnsheep, and Suffolk ewes

Concentrations of folates in serum and milk were determined during the first two parities in 7 Suffolk, 12 Finnsheep, and 15 Romanov ewes at 0 (mating), 60, 110, and 140 d of gestation and 1, 7, 14, 21, and 50 d of lactation. The number of lambs born at first and second parturitions was 1.38 +/- .13 and 1.71 +/- .13 for Suffolk, 2.00 +/- .32 and 2.33 +/- .57 for Finnsheep, and 2.67 +/- .24 and 3.20 +/- .22 for Romanov, respectively, and the concentration of folates at d 0 was 1.17 +/- .21, 1.87 +/- .19, and 2.14 +/- .17 ng/mL, respectively. During gestation, serum concentrations of folates declined in the three breeds, more quickly in Romanov and Finnsheep (from d 0 to 60) than in Suffolk (from d 0 to 110). This decline was followed by an increase in serum concentrations of folates from d 110 to 140 of gestation in the three breeds; the largest increase was observed in Romanov (breed x quadratic effect of time, P = .001). During lactation, Romanov had higher serum concentrations of folates than Finnsheep, which in turn had a higher concentration than Suffolk (P = .001). Colostrum of Romanov had the highest concentration of folates (164.9 +/- 11.9 ng/mL), followed by that of Finnsheep (125.0 +/- 9.5 ng/mL) and Suffolk (98.2 +/- 13.3 ng/mL). On d 7 of lactation, concentration of folates was similar in milk of Romanov (97.1 +/- 5.6 ng/mL) and Finnsheep (94.9 +/- 4.0 ng/mL) and was higher than in Suffolk (72.4 +/- 3.7 ng/mL). From d 14, the concentration of milk folates was similar among breeds and decreased slowly to approximately 40 ng/mL at d 50 (breed x quadratic effect of time, P = .005). The changes in serum concentration of folates during gestation of ewes were similar to those observed in sows, suggesting that exogenous supply of folates may not be optimal in ewes during gestation and lactation.

Lactation performance of sows fed a bulky diet during gestation and receiving growth hormone-releasing factor during lactation

Forty-eight crossbred gilts were used in an experiment with a 2 x 2 x 2 factorial arrangement of treatments. Treatments were control or bulky diet during gestation (4.1 vs 15.3% crude fiber), number of meals served daily in lactation (2 vs 4), and three daily s.c. injections of saline or of 1 mg of a human growth hormone-releasing factor analog (GRF-AN) from d 3 to 29 of lactation. Weights of pigs were recorded weekly until weaning on d 33. On d 29 of lactation, milk yield was estimated and a milk sample was obtained the next day. Jugular blood samples were collected from the sows on d 3 and 28 of lactation. Feed and water intake of sows were recorded throughout the study. Feeding the bulky diet decreased water intake in gestation (P < .001) and increased feed intake in lactation (P < .03). The number of meals served daily had no effect on feed intake during lactation (P > .1). Injections of GRF-AN increased IGF-I concentrations in blood (P < .01) and in milk (P < .001) and decreased backfat thickness (P < .001) and feed intake (P < .001) of sows during lactation. Pigs from sows injected with GRF-AN weighed more on d 14 (P < .05) and had a tendency to weigh more on d 7 (P = .09) and d 21 (P = .06). The incidence of sows showing estrus within 10 d of weaning was reduced with exogenous GRF (P < .01). The use of exogenous GRF in lactating sows may therefore have beneficial effects on growth of the pigs, yet the optimal nutritional and hormonal conditions needed for GRF to exert its full potential still need to be determined.

Serum clearance and urinary excretion of pteroylmonoglutamic acid in gestating and lactating dairy cows

The present experiment was undertaken to verify if the demand of tissues for pteroylglutamic (folic) acid, evaluated by serum clearance and urinary excretion of folates, is different between multiparous dairy cows in late gestation (five gestating dry cows, 52.6 (SD 8.4) d before parturition), and in early lactation (four lactating non-gestating cows, 18.0 (SD 5.9) d after parturition). On day 1 the cows received one intravenous (i.v.) injection of 50 micrograms pteroylmonoglutamic acid/kg body weight (BW). Blood samples were taken at 0, 5, 15, 30 min, 1, 2, 4, 8 and 24 h after the i.v. injection. On day 3 the cows received one intramuscular (i.m.) injection of 0.3 mg pteroylmonoglutamic acid/kg BW. Blood and urine samples, as well as urine volume, were taken at 0, 1, 2, 4, 8, 12, 24, 36 and 48 h after the i.m. injection. On days 5, 6 and 7 a daily i.m. injection of 0.5 mg pteroylmonoglutamic acid/kg BW was given in an attempt to saturate tissues with folates. Then the cows received one i.v. (day 8) and one i.m. (day 10) injection of pteroylmonoglutamic acid according to the same procedures described previously for days 1 and 3. On day 12 plasma volume was determined. Before tissue saturation, serum clearance of folates during the 24 h following an i.v. injection was similar for gestating and lactating cows but after tissue saturation serum clearance was slower for lactating than gestating cows (stage x saturation, P = 0.04). The percentage of folates excreted in urine was not affected by the physiological stage (P > or = 0.6) or the level of tissue saturation (P > or = 0.5). In conclusion, serum clearance and urinary excretion of pteroylmonoglutamic acid seem to support the hypothesis that, in multiparous cows, although there are no deficiency symptoms, tissue demand for folic acid is high, especially during gestation.

Gestation and lactation of dairy cows: a role for folic acid?

Twenty-four multiparous and 16 primiparous dairy cows were assigned by parity, BW, and milk production to 20 blocks of 2 cows each. Within each block, the cows were injected weekly with either 0 or 160 mg of folic acid from 45 d after mating to 6 wk after parturition. Supplementary folic acid augmented the placental and colostral transfer of folates to the calf but had no effect on blood hemoglobin, birth weight, or growth and feed intake of the calf during the first 10 wk of life. The supplemental folic acid increased serum folates but had no marked effect on blood hemoglobin and BW of cows. Supplementary folic acid tended to increase milk folates, milk production, and the percentage of milk protein during the last half of the lactation curve but had no effect on milk folates and milk production during the first 6 wk after parturition when the injections of folic acid increased the percentage of milk protein in multiparous cows but had no effect on primiparous cows. The supply of folates by the diet and the synthesis by ruminal microflora is sufficient to prevent folic acid deficiency in dairy cows and to maintain normal gestation and lactation, but not to achieve maximal production of milk and protein in multiparous dairy cows during gestation and lactation.

Pteroylglutamic (folic) acid in different feedstuffs: the pteroylglutamate content and an attempt to measure the bioavailability in pigs

Sixty piglets selected after weaning at 4 weeks of age were assigned to five replicates of twelve animals each. In each of these replicates the postprandial variations in serum pteroylglutamate after the ingestion of twelve sources of dietary pteroylglutamic acid were recorded twice weekly at 10 and 16 weeks of age. In six of these sources of pteroylglutamic acid the chemically pure form of the vitamin was incorporated into a semi-purified diet at concentrations varying between 0 and 1.0 mg/kg. The six other sources were provided by a soya-bean meal, rapeseed meal, maize, barley, wheat, and a commercial vitamin premix. The concentrations of pteroylglutamates measured by radioimmunoassay in the different feedstuffs were, in most cases, far from the values reported in the literature, except for maize. Indeed, while total pteroylglutamates in barley, wheat and rapeseed meal were lower by 35-56%, 17-50% and 60% respectively compared with references values, the corresponding values for soya-bean meal ranged from one third to twice as much. The area under the curve (AUC) of the pre- and postprandial (1, 2, 3, 5 and 7 h) serum pteroylglutamate following ingestion of increasing levels of chemically pure pteroylmonoglutamic acid was used to derive a regression for the 100% bioavailability of dietary pteroylglutamic acid. The corresponding AUC for the feedstuff sources of pteroylglutamates were used in the regression to determine the proportion of bioavailable pteroylglutamates out of total pteroylglutamates measured in these ingredients. No relationship (P > 0.66) was found between the level of chemically pure dietary pteroylmonoglutamic acid and the postprandial AUC. In fact, there was no significant (P > 0.11) increase in the postprandial concentration of serum pteroylglutamate for any of the pteroylglutamate sources used except for wheat. Moreover, values tended (P < 0.08) to be lower at 5 and 7 h postfeeding except for wheat and barley. It was hypothesized that this decrease is probably linked to the postfeeding variation in bile secretion which drains considerable amounts of circulatory pteroylglutamates. The results of the present experiment indicate that further research on analytical procedure is needed in order to provide a reliable method for measuring concentrations of pteroylglutamic acid in different sources of a given feedstuff used in pig feeding.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of bulky diets based on wheat bran or oat hulls on reproductive performance of sows during their first two parities

The aim of the present study was to determine the effect of different degrees of bulkiness in the gestation diet on reproductive performance of sows during their first two parities. The density of the diets was modified by incorporating a high proportion of fibrous ingredients (wheat bran and corn cobs in Diet 2 and oat hulls and oats in Diet 3). A diet without fibrous ingredients was used as a control (corn and soybean meal in Diet 1). Although all the gestation diets were formulated to provide the same daily intake of the major nutrients, sows fed Diet 3 were the lightest and had the lowest backfat thickness (P < or = .05) during both parities, and those fed Diet 2 were the heaviest and the fattest (P < or = .05) during the second parity. These results seem to indicate an overestimation of the calculated nutritive value of Diet 3, whereas those obtained with Diet 2 seemed to be linked to its marked effect on behavior of sows during the second parity. There was no marked effect (P > .11) of treatments on the number of pigs born alive, on preweaning mortality, or on the weaning-to-estrus interval. At parturition, total litter weight was similar among treatments in the first parity, whereas in the second parity it was greater (P < or = .05) in sows fed Diet 2 than in those fed Diets 1 and 3. In both parities, feed intake of the common lactation diet given during lactation was 5% higher (P < or = .05) for sows fed Diet 3 during gestation than for sows fed the other diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Concentrations of folates in ruminal content of steers: responses to a dietary supplement of folic acid in relation with the nature of the diet

In an attempt to evaluate the ruminal effects of dietary supplements of folic acid, eight steers (352 +/- 27 kg BW) fitted with a ruminal cannula were randomly assigned to a replicated 4 x 4 Latin square design. The treatments were 70% rolled barley + 30% timothy hay (HC), HC + 2 mg of folic acid per kilogram of BW (HC + FA), 30% rolled barley + 70% timothy hay (HF), and HF + 2 mg of folic acid per kilogram of BW (HF + FA). After 5 wk of adaptation to the dietary treatments, ruminal contents were sampled over three consecutive days, at 1, 2, 4, 8, 12, and 23 h after feed distribution. Concentrations of folates in solid and liquid ruminal fractions were increased by the dietary supplement of folic acid (P = .0001) and by the ingestion of concentrate compared with hay-based diets (P < .05). Preprandial concentrations of serum folates were not affected by the nature of the diet when steers received no folic acid but the increase of serum folates induced by the dietary supplement of folic acid was more important in steers fed concentrates than in those fed hay-based diets (diet x supplement of folic acid interaction P = .002). Microbial protein (P = .004) and microbial mass (P = .002) in ruminal fluid were increased with concentrate-based diets compared with hay-based diets; folic acid did not have any effect on these variables (P > .05). In conclusion, concentrations of folates in ruminal contents were affected by dietary supplements of folic acid and by the nature of the diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of diet and folic acid addition on digestibility and ruminal fermentation in growing steers

Eight ruminally fistulated steers (352 +/- 27 kg BW) were used in a replicated 4 x 4 Latin square design. Treatments were 1) 70% rolled barley +30% timothy hay (HC), 2) HC+folic acid (2 mg/kg BW; HC+F), 3) 30% rolled barley + 70% timothy hay (HF), and 4) HF+F. Total tract apparent digestibility of DM and CP were greater (P < or = .05) in steers fed the HC diet, whereas that of ADF and NDF was greater (P < .001) in steers fed the HF diet. Supplemental dietary folic acid had no effect on either of the forementioned variables, regardless of whether the animal received the HC or the HF diet. To compare ruminal DM disappearance, nylon bags containing either hay or barley were incubated in the rumen of each steer for 4, 8, 12, 24, and 48 h. Ruminal DM disappearance of hay and barley was affected (P < .05) by the type of diet fed but not by the addition of folic acid to either diet. Ruminal fluid was sampled on three consecutive days, at the following postprandial hours: 1, 2, 4, 8, 12, and 23. Differences in ruminal pH and individual VFA among treatments were attributable to the type of diet fed. Changes in ruminal VFA concentrations at various times after feeding were altered with folic acid addition; however, these modifications were not sufficient to affect in a significant way either ruminal or total tract digestibility.

Age-related changes in secretion rate and post-secretory metabolism of growth hormone in swine

The effect of age on growth hormone (GH) metabolism and GH-releasing factor (GRF)-induced GH concentrations were studied in 7 young (3 mo, 39 kg) and 7 old (30 mo, 156 kg) Yorkshire x Landrace female pigs. Jugular catheters were surgically inserted and 60 hr later total serum volume was determined. The following day, all animals were infused for 3 hr with GH (30.3 ng.min/kg B.W.) in order to calculate GH metabolic clearance rate (MCR), secretion rate (SR) and half-life (t 1/2). Two days later, 15 micrograms/kg of GRF was injected i.v. into all pigs. On a per animal basis, aging increased (P < .01) MCR (299 vs 132 ml/min), SR (714 vs 422 ng/min) and serum volume (6.6 vs 2.01), whereas t1/2 was unaltered (P > .1). Basal GH concentrations were lower in older pigs (P < .10) but the GRF-induced GH concentrations (measured as GH peak or area under the curve, AUC) were not affected by age (P > .1). Yet, when induced total GH secretion (AUC x MCR) and average total serum GH (mean GH post-injection x serum volume) were calculated per pig, these variables significantly increased between 3 and 30 mo of age. Basal IGF-I concentrations were lower in older pigs (P < .01), yet, there was a tendency (P = .10) for these pigs to show a greater IGF-I response to GH infusion. The present data therefore indicate that age alters both SR and post-secretory metabolism of GH.(ABSTRACT TRUNCATED AT 250 WORDS)

Forestomach motility and behavior of bull calves according to changes in regimen

Six 23-week-old bull calves were randomly assigned to a crossover design to study the effects of hay and concentrates given separately (A), silage and concentrates given in complete mixed ration (B), or given separately (C) on reticulo-ruminal motility and eating and resting behaviors after an adaptation period of 14 days (day 14). The effects of a change from one treatment to another on the same variables were also investigated (day 1). The differences observed between day 1 and day 14 indicate that a change in regimen, even not drastic, seems to affect reticulo-ruminal motility, rumination pattern, ruminal inactivity, and resting behavior. As expected, the number of triphasic and biphasic reticular spike bursts, as well as eating and resting behaviors, were affected by the type of forage ingested (A vs. C) on day 14 (p < or = 0.05). Moreover, the mode of distribution of concentrates affected also the variables measured (p < or = 0.05). Although the length of particles in complete mixed ration (B) was the same than in silage and concentrates given separately (C), the effect of regimen B on many variables was similar to that of regimen A or intermediate between A and C. The effect of regimens B and C was similar only for the rumination pattern, even though the number of boluses regurgitated for rumination differed (p < or = 0.05).

Effect of long-term addition of folic acid on folate status, growth performance, puberty attainment, and reproductive capacity of gilts

Three groups of 34 gilts received, from 9 wk of age until slaughter at 7 wk of gestation, diets supplemented with either 0, 5, or 15 mg/kg of folic acid. The concentration of serum folates increased linearly (P < or = .05) with the level of added folic acid. Although the growth performance was not influenced by the treatments during the overall growing period, feed intake (P < or = .10) and body weight gain (P < or = .05) from 17 to 21 wk of age increased linearly as folic acid level in the diet increased. Age and body weight at puberty as well as body weight gain during gestation were not influenced (P > or = .32) by treatments. Dietary folic acid addition did not affect (P > or = .21) either total weight and empty weight of uterine horns or ovarian total weight, stroma weight, and number and weights of corpora lutea. No treatment effect (P > or = .35) was observed on placental surface, number of placental areolae, litter size, fetus weight, or total litter weight or on fetal DNA, RNA, and protein. However, the concentration of folates in fetuses increased linearly (P < or = .03) with the addition of folic acid in the dam's diet. In conclusion, although a dietary addition of as high as 15 mg/kg of folic acid seemed to influence growth performance of gilts by the end of the growing period, it did not affect age at puberty.(ABSTRACT TRUNCATED AT 250 WORDS)

Transient stray voltage: is it detrimental to growth performance, health status and welfare of market pigs?

The effects of transient stray voltage associated with an alternating current were evaluated in growing-finishing pigs from 9 to 22 weeks of age. Seventy-two pigs were assigned to 9 blocks of 8 animals each. In each block, the following treatments were randomly distributed: a constant voltage differential created between the feeder or drinker and the metallic floor (woven wire), at a level of 0 volt plus 2-volt pulses (0 V-2 V), 2 volts plus 3-volt pulses (2 V-5 V), 5 volts plus 3-volt pulses (5 V-8 V), and a control treatment without any voltage differential (0 V-0 V). The constant voltage was applied 24 h per day. The pulses of 3 s duration were in the form of an increase in the amplitude of the constant 60-Hz signal. One pulse appeared every 20, 40 and 100 s during the hour following feed distribution and every 60, 120 and 300 s during the rest of the day. The animals were fed ad libitum and received fresh feed twice per day. Once during the 2-week periods at 9-10, 13-14, 17-18 and 21-22 weeks of age, the behaviour of the pigs was recorded during the hour following the two daily feed distributions. Animal weights and blood samples were taken every 2 weeks, from 9 to 21 weeks of age. No significant effect of transient stray voltage on any of the variables measured for the feeding, drinking, sitting or lying activities was found (p > 0.05). At 9-10 weeks of age, the number of rooting bouts was higher for the 5 V-8 V treatment (p = 0.03) and the number of events of butting the penmate was higher for the 2 V-5 V treatment (p = 0.05). Although the water and feed intake did not differ between treatments (p > or = 0.39), the average daily gain of the control group was lower than that of treated groups (p = 0.04) at 9 and 10 weeks of age, while the pigs submitted to a 2 V-5 V treatment had a higher daily gain than the pigs in the other treatment groups (p = 0.05) at 17 and 18 weeks of age.(ABSTRACT TRUNCATED AT 400 WORDS)

Responses of serum folates of preruminant and ruminant calves to a dietary supplement of folic acid

The effect of dietary supplemental folic acid on serum folates of preruminant and ruminant calves was studied. In Trial 1, doses of 0, .07, .14, .28, and .56 mg of folic acid per kilogram of BW were added to the milk of preruminant calves. In Trial 2, doses of 0, .5, 1, 2, and 4 mg of folic acid per kilogram of BW were incorporated into the concentrates of ruminant heifers. In the first part of each trial, serum folates were determined in blood samples taken 0, 1, 2, 4, 8, 16 (both trials), and 32 h (Trial 2) after a single meal supplemented with folic acid. In the second part of the two trials, the supplement of folic acid was given in feed during seven consecutive days. Blood samples were taken the day before the trial and subsequently every day during 7 d. In preruminant and ruminant calves, the area under the curve and the peak of concentration of serum folates after a meal increased with the dose ingested (P less than or equal to .05, linear and quadratic effect of doses, respectively) but the amount of folic acid needed to obtain a similar response was lower for preruminant than for ruminant calves. In preruminants, the time to reach the maximal concentration was 3 to 4 h after the meal, whatever the dose ingested (P less than or equal to .05), whereas in ruminants this time decreased with the dose ingested (quadratic effect of treatment, P less than or equal to .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of feeding regimen on behavior of growing-finishing pigs supplemented or not supplemented with folic acid

The effect of restricted feeding on the frequency of abnormal behaviors and gastric ulcers was investigated in 72 market pigs. Half of the pigs were fed restricted (R) amounts of feed twice a day (0800 and 1600) and received 90 to 95% of the intake recorded for the other half, which were allowed ad libitum (A) access to feed with addition of feed once a day at 0800. In each feeding group, 24 pigs were supplemented with folic acid. The animals were housed in pairs and the behavior of each animal was recorded during 24 h at 18 and 20 wk of age. The results showed that the A group ate more frequently during light hours than the R group at 18 wk, but not at 20 wk. However, the frequency of eating behavior was higher in the R group than in the A group at 20 wk during the 2 h after feed distribution. Feeding regimen had an effect on the frequency of redirected behaviors during the 2 h preceding feed distribution. The percentage of time spent nibbling on the penmate was higher in R than in A pigs at 18 wk, whereas that of rooting on the penmate was higher at 20 wk. Moreover, the proportion of pigs performing redirected behaviors was higher in the R than in the A group at both ages. The overall frequency of gastric ulcers was similar in pigs given the two feeding treatments, but severe ulcers were more frequent in the R than in the A group. Some interactions were also found between feeding regimen and folic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of continuous stray voltage on health, growth and welfare of fattening pigs

The effects of continuous stray voltage were evaluated on growing-finishing pigs between the ages of 8 and 21 weeks. Seventy-two pigs were assigned to six blocks of 12 animals each. The following treatments were randomly distributed in each block according to a 2 x 3 factorial design: feeding level (restricted or ad libitum) and voltage level (0, 2 or 5 volts (V) as a difference of potential between feeder or drinker and the metallic floor). During daytime, stray voltage at 5 V decreased (p less than 0.05) the eating frequency in both feeding groups and the drinking frequency in restricted-fed pigs. The mean duration of drinking bouts and the total time spent at the drinker were also lower (p less than 0.05) in this last group during the hour following meal distribution. Daily feed intake and average daily gain were lower (p less than 0.05 and less than or equal to 0.08, respectively) in the 5 V group than in the 2 V and the control groups from 17 to 21 weeks of age. Finally, gastric lesions, hematological and biochemical variables were not affected (p greater than 0.05) by stray voltage.

Effects of a parenteral supplement of folic acid and its interaction with level of feed intake on hepatic tissues and growth performance of young dairy heifers

Forty-seven dairy heifers of approximately 10 d of age were assigned to a factorial experiment in which a supplement of folic acid (0 or 40 mg) administered weekly by i.m. injection and level of feed intake were the two factors studied. The heifers were weaned after 5 wk of experimentation. Following weaning, and until the end of the experiment, 11 wk later, they had ad libitum access to grass hay and concentrates at two different levels, ad libitum or restricted, to allow a body weight gain of 700 g/d. A supplement of folic acid (P less than .05) and ad libitum access to feed (P less than .05) increased the mean concentration of serum folates. Blood hemoglobin and packed cell volume were not affected by the level of feed intake. However, they were both increased (P less than .05) by the supplement of folic acid. Average daily gain was analyzed over three different periods: 0 to 5 wk (before weaning), 5 to 10 wk, and 10 to 16 wk. Average daily gain was increased by the supplement of folic acid during the second period (P less than .05) and by ad libitum access to feed during the last two periods (P less than .05). Ad libitum access to feed increased (P less than .05) weight of the liver, decreased the (P less than .05) concentrations of RNA and DNA, and increased (P less than .05) the ratios of protein/DNA and RNA/DNA. The supplement of folic acid decreased (P less than .05) weight of the liver and increased the ratio RNA/DNA (P less than .05). These effects of supplement of folic acid on growth performance and on hematological cells may reflect a lack of folic acid during the weeks after weaning.

Effects of intramuscular injections of folic acid on serum folates, haematological status and growth performance of growing-finishing pigs

In a first trial, 48 piglets aged 5 weeks, grouped into 6 blocks of 8 pigs each, were used to determine the effect of intramuscular injections of folic acid on serum folates, haematological status, growth performance and carcass characteristics. Each block consisted of 2 pens of 4 pigs; in one pen, pigs received, by weekly intramuscular injections, an increasing volume of a solution containing 5 mg/ml folic acid, while in the other the animals were non-injected controls. The concentration of serum folates in treated pigs was 19% higher (P = 0.005) than in controls. There was no effect of treatment (P greater than or equal to 0.29) on haemoglobin and haematocrit. During the starting period, (5-11 weeks) average daily gain was not influenced by folic acid injections but feed intake and feed conversion were decreased (P = 0.07 and P = 0.05 respectively). No effect of folic acid (P greater than or equal to 0.23) was noted from 11-23 weeks of age, suggesting that the supplement was suboptimal during the growing-finishing period. In a second trial, 72 piglets aged 9 weeks were assigned to 6 blocks of 12 animals each. The following treatments were randomly distributed in each block according to a 2 x 3 factorial design: level of feeding (restricted vs ad libitum) and weekly intramuscular injections of increasing volume of solutions containing either 0, 15 or 30 mg/ml of folic acid. The variables studied were the same as in Trial 1. Concentrations of serum folates varied quadratically (P = 0.0001) with the dose injected, a plateau being attained with injections of 15 mg/ml. There was no effect of treatment (P = 0.043) on haemoglobin and haematocrit. During the growing period (9-15 weeks), no effect (P greater than or equal to 0.72) of folic acid was noted on growth performance. However, during the finishing period (15-21 weeks), folic acid given at a dose of 30 mg/ml decreased (P = 0.006) feed intake while no effect (P greater than or equal to 0.13) of the vitamin supplementation was noted on average daily gain and feed conversion. In both trials, there was no effect (P greater than or equal to 0.21) of any treatments on carcass characteristics. These results indicate that a supplement of folic acid administered by intramuscular injections was effective in increasing concentration of serum folates of starting or growing-finishing pigs. This supplement may be associated with a decrease in feed intake.