Raw mung beans as a protein source for bred gilts

A study involving 546 crossbred gilts from six seasons was conducted to evaluate raw mung beans as a partial replacement for soybean meal in diets for gilts during gestation. Gilts were randomly allotted to either a control sorghum grain-soybean meal diet or a diet in which a portion of the soybean meal was replaced with mung beans. In the first three seasons, gilts were fed diets in which the protein supplement was totally soybean meal or 89% mung beans (high level) and 11% soybean meal. In the last three seasons the level of mung beans in the supplemental protein was reduced to 61% mung beans with 39% soybean meal (moderate level). Feeding the high level of mung beans decreased (P less than .05) weight gain during gestation and reduced (P less than .05) weight loss during lactation compared with gilts fed the control diet or the moderate level of mung beans. Little difference was noted in litter size at birth, but litter size at 21 d for gilts fed moderate levels of mung beans was less (P less than .05) than for gilts fed the control diet or the high level of mung beans. Little difference was noted in survival rate to 21 or 42 d or individual and litter weights at birth and 21 d. Pig and litter weights at 42 d, however were reduced in gilts fed the high level of mung beans (P less than .05 and P less than .10, respectively) compared with the control diet.(ABSTRACT TRUNCATED AT 250 WORDS)     

Response of swine to periparturient vitamin C supplementation

Two experiments were conducted, involving 68 third-litter sows and 20 first-litter gilts in Exp. 1 and 82 first-litter gilts in Exp. 2. On d 108 of gestation, the dams were moved into individual crates, stratified by parity and breed, and randomly assigned within strata, to one of two treatments: (1) fed a basal 16% protein corn-soybean meal diet, 1.8 and 2.7 kg once daily before farrowing and for the first 7 d of lactation, respectively, and then ad libitum until pigs were weaned at 28 d of age, and (2) fed the basal diet plus 1 g of L-ascorbic acid (vitamin C)/dam daily from d 108 of gestation through d 7 of lactation and on the same feeding schedule as for treatment 1. In Exp. 1, no effect of vitamin C supplementation was observed in sows or gilts on total pigs born/litter, number of live pigs/litter or average live pig weight at birth, 7 or 28 d of age, or on plasma vitamin C concentration of dams at d 108 of gestation or d 7 of lactation or of pigs at birth, 7 or 28 d of age. However, there was a lower (P less than .01) plasma vitamin C concentration of the dams at d 7 of lactation than at d 108 of gestation. Plasma vitamin C concentration also declined (P less than .01) as pigs aged. In Exp. 2, with all gilts, vitamin C supplementation again showed no effect on any of the reproductive traits measured in Exp. 1. It is concluded that daily supplementation of 1 g of vitamin C to either sows or gilts from d 108 of gestation through d 7 of lactation has no beneficial effect on the reproductive or lactation performance of swine.     

Limited and excess dietary protein during gestation affects growth and compositional traits in gilts and impairs offspring fetal growth

The aim of this study was to investigate whether dietary protein intake during gestation less than or greater than recommendations affects gilts growth and body composition, gestation outcome, and colostrum composition. German Landrace gilts were fed gestation diets (13.7 MJ of ME/kg) containing a low (n = 18; LP, 6.5% CP), an adequate (n = 20; AP, 12.1%), or a high (n = 16; HP, 30%) protein content corresponding to a protein:carbohydrate ratio of 1:10.4, 1:5, and 1:1.3, respectively, from mating until farrowing. Gilts were inseminated by semen of pure German Landrace boars and induced to farrow at 114 d postcoitum (dpc; Exp. 1). Energy and protein intake during gestation were 33.3, 34.4, and 35.8 MJ of ME/d (P < 0.001) and 160, 328, and 768 g/d, respectively, in LP, AP, and HP gilts (P < 0.001). From insemination to 109 dpc, BW gain was least in LP (42.1 kg), intermediate in HP (63.1 kg), and greatest in AP gilts (68.3 kg), whereas increase of backfat thickness was least in gilts fed the HP diet compared with LP and AP diets (3.8, 5.1, 5.0 mm; P = 0.01). Litter size, % stillborn piglets, and mummies were unaffected (P > 0.28) by the gestation diet. Total litter weight tended to be less in the offspring of LP and HP gilts (14.67, 13.77 vs. 15.96 kg; P = 0.07), and the percentage of male piglets was greater in litters of HP gilts (59.4%; P < 0.01). In piglets originating from LP and HP gilts, individual birth weight was less (1.20, 1.21 vs. 1.40 kg; P = 0.001) and birth weight/crown-rump length ratio was reduced (45.3, 46.4 vs. 50.7 g/cm; P = 0.003). Colostrum fat (7.8, 7.4 vs. 8.1%) and lactose concentrations (2.2, 2.1 vs. 2.6%) tended to be reduced in LP and HP gilts (P = 0.10). In Exp. 2, 28 gilts (LP, 10; AP, 9; HP, 9) were treated as in Exp. 1 but slaughtered at 64 dpc. At 64 dpc, LP gilts were 7% lighter than AP gilts (P = 0.03), whereas HP gilts were similar to AP gilts. Body composition was markedly altered in response to LP and HP feeding with less lean (P < 0.01) and greater fat content (P = 0.02 to 0.04) in LP and less fat content (P = 0.02 to 0.04) in HP gilts. Fetal litter weight and number, and embryonic survival at 64 dpc were not affected by the diets. These results indicated that gestation diets containing protein at 50 and 250% of recommendations and differing in protein:carbohydrate ratio led to marked changes in protein and fat metabolism in gilts resulting in fetal growth retardation of 15%, which mainly occurred during the second half of gestation.     

Riboflavin requirement of lactating swine

Twenty-five crossbred gilts and 25 crossbred sows were used in an experiment to estimate the riboflavin requirement of lactating swine. During gestation the females were fed a 12% crude protein, corn-soybean meal diet that was marginal in riboflavin content, i.e., 2.3 mg/kg. After farrowing, litter size was equalized across lactation diets within each parity category. The basal, 14% crude-protein corn-soybean meal lactation diet was supplemented to provide five levels of dietary riboflavin: 1.25, 2.25, 3.25, 4.25 and 5.25 mg/kg. Five gilts and five sows were fed each dietary treatment. Each dam was provided her assigned diet ad libitum during the 24-d lactation; piglets were not provided supplemental feed. The erythrocyte glutathione reductase activity coefficient (EGRAC), an indicator of riboflavin status, was measured on blood samples obtained from the dams and their piglets on d 1 and d 24 postpartum. On d 1, the mean EGRAC of gilts was slightly higher than that of sows, while piglet EGRAC was similar regardless of maternal age. On d 24 gilts and their piglets had higher average EGRAC (P less than .01) than did sows and their piglets. Thus, there was a treatment x dam age interaction (P less than .05). Lactation performance criteria gave further evidence of similar treatment x age group interactions. Gilts fed the diet containing 1.25 ppm riboflavin had higher piglet mortality, consumed less feed and lost more weight (P less than .05) for each criterion than did sows fed the same diet. Despite these observations, the broken-line estimates of the riboflavin requirement, based on EGRAC, for gilts and sows were 16.3 and 16.2 mg/d, respectively. The EGRAC values for piglets closely paralleled those of their dams regardless of treatment, suggesting that there is no mechanism to protect the nursing piglets from a maternal dietary deficiency of riboflavin.     

Effects of increased dietary energy and protein during late gestation on mammary development in gilts

Thirty-two gilts were used to evaluate the effects of increased dietary energy and CP during late gestation on mammary development. On d 75 of gestation, gilts were assigned randomly in a 2 x 2 factorial arrangement to adequate (5.76 Mcal ME/d) or increased (10.5 Mcal ME/d) energy and adequate (216 g CP/d) or increased (330 g CP/d) protein. On d 105 of gestation, gilts were slaughtered and total mastectomies were performed. Mammary tissue was separated into mammary parenchymal and mammary extraparenchymal stromal tissue and analyzed for DNA, RNA, protein and lipid. No interactions between dietary energy and protein level were detected (P greater than .20). When adjusted for number of mammary glands and maternal BW (weight of the sow less the weight of the fetuses), mammary parenchymal weight was 27% greater (P less than .03) in gilts fed adequate energy than in gilts fed increased energy, but mammary extraparenchymal stroma weight was unaffected by dietary energy level. Total mammary parenchymal DNA was 30% greater in gilts fed adequate energy than in gilts fed increased energy (P less than .03). Total mammary parenchymal RNA (P less than .02) and total mammary parenchymal protein (P less than .02) also were greater in gilts fed adequate energy than in gilts fed increased energy. Dietary protein level did not affect mammary variables measured, except that increased dietary protein tended to reduce mammary extraparenchymal stromal weight (P less than .09). Increased dietary protein between d 75 and d 105 of gestation did not benefit mammary development, but increased dietary energy was detrimental to development of mammary secretory tissue.     

Effect of dietary folic acid supplementation on sow performance through two parities

One hundred fifty-three gilts were maintained in three breeding groups and fed gestation-lactation diets supplemented with either 0 (control), 1.65 or 6.62 mg of supplemental folic acid/kg of diet for two consecutive parities. Serum folate concentrations of sows were linearly (P less than .05) increased by dietary additions of folic acid during both gestation and lactation, but serum glucose and urea concentrations were unaffected by treatment. Serum folate concentrations decreased from breeding to d 60 and 90 of gestation and then increased through lactation for all treatments. Number of pigs born and live pigs at birth, d 14 and d 21 were quadratically (P less than .05) increased by folic acid additions. Average pig weights were similar among treatments (P greater than .10) on both d 0 and 14 of lactation but were less (P less than .01) than the other treatment groups on d 21 for pigs from sows fed the 1.65 mg/kg treatment. Litter weights were quadratically (P less than .01) increased on d 0 and d 14 by folic acid supplementation. Sow weight gain and backfat thickness loss were unaffected by treatment during gestation (P greater than .06); sow weight loss and backfat thickness loss increased quadratically with increasing level of folic acid during lactation (P less than .06 and .05, respectively). More control sows exhibited estrus by d 7 postweaning than sows receiving folic acid supplementation in parity I (P less than .05); however, no differences (P greater than .10) were detected among treatments by d 14, nor were any differences observed by d 7 in parity II. Conception rate was unaffected by folic acid additions. Dietary folic acid supplementation improved sow reproductive performance by increasing the number of pigs born alive.     

Behavior, reproduction, and immunity of crated pregnant gilts: effects of high dietary fiber and rearing environment.

The objective of this study was to examine effects of increased gut fill and diverse developing environments on pregnant gilts' behavior and physiology. Gilts were cross-fostered at 1 d of age and transferred to either an indoor or outdoor production unit. Littermate gilts remained in their different environments during development and were moved into individual gestation crates in an indoor gestation unit. Of the 42 gilts, 19 were fed a control diet of fortified sorghum-soybean meal and 23 were fed the same diet with 25% beet pulp (high fiber). Control sows ate 2.0 kg/d and high-fiber sows ate 2.67 kg/d in a large pellet (thus resulting in approximately equal energy intake and differing total dietary intakes). Pregnant gilts had behavior and immune measures sampled at 30, 60, and 90 d of gestation. The day x diet interaction was significant (P = 0.01) for duration of standing: sows fed high-fiber diets stood less on d 30, but on d 60 and 90 they and the control sows stood for a similar duration. Sham chewing duration and frequency showed significant (P < 0.05) effects of gestation stage x diet x environment. Gilts reared outdoors and fed high fiber increased sham chewing over gestation, whereas all other treatment groups decreased this behavior over time. Outdoor-reared gilts had greater (P < 0.05) frequency and duration of drinking behavior than indoor-reared gilts. White blood cell numbers were higher (P < 0.05) for gilts fed high-fiber diets than for gilts fed the control diet. Immune (humoral and cellular systems) and reproductive measures (farrowing rate and litter size) and plasma cortisol concentrations were generally not influenced (P > 0.10) by diets and rearing environments, suggesting that in spite of significant changes in behavior and feed intake gilts' immune systems were not suppressed or enhanced. Behavioral data alone suggested that indoor-reared gilts showed fewer behavioral adaptations to the crates than outdoor-reared gilts. However, immune measures did not indicate that any treatments resulted in physiological effects indicative of stress.     

Impact of betaine on pig finishing performance and carcass composition

Two experiments were conducted to evaluate the effect of betaine supplementation of finishing diets on growth performance and carcass characteristics of swine. Experiment 1 included 288 pigs in a 2 x 2 x 3 factorial arrangement of treatments consisting of barrows and gilts of two genetic populations fed diets with 1.25 g/kg supplemental betaine from either 83 or 104 kg to 116 kg and control pigs fed betaine-devoid diets. Pigs were housed three pigs per pen with eight replicate pens per treatment. Diets were corn-soybean meal-based with 300 ppm added choline. Genetic populations differed (P < 0.05) in fat depth (2.24 vs 2.93 cm) and longissimus muscle depth (53.8 vs 49.1 mm) at 116 kg. Betaine reduced feed intake (P < 0.05); however, real-time ultrasound measurements were not affected. In Exp. 2, 400 pigs were used in a 2 x 2 x 2 factorial arrangement of treatments to evaluate the effect of sex (barrow or gilts), betaine (0 or 1 g/kg of diet), and crude protein (CP) (0.70% lysine = 12.7% CP or 0.85% lysine = 15.0% CP) when fed from 60 to 110 kg live weight. Pigs had been assigned to either a high- or low-protein feeding regimen at an average initial weight of 11.3 kg and were maintained on their respective protein levels throughout the experiment. For a 56-d period from 61.7 kg to 113.6 kg, pigs were fed diets with 300 ppm added choline. Within each protein level, pigs were randomly assigned to diets containing 0 or 1 g/kg betaine. Pigs were group-housed (four to five pigs per pen). Pig weight and feed intake were recorded every 28 d. Real-time ultrasound measurements were recorded initially and at d 28 on 64 pigs, and on all pigs prior to slaughter. Growth rate was fastest and feed intake greatest for barrows (P < 0.05) and for pigs receiving 12.7% crude protein. A crude protein x betaine interaction (P < 0.05) was observed from d 28 to 56 with pigs fed the 15% CP diet growing fastest when supplemented with 1 g/kg betaine, and pigs receiving the 12.7% CP diet growing fastest when the diets contained 0 g/kg betaine. Gilts more efficiently (P < 0.05) converted feed into body weight gain, as did pigs receiving the 12.7% CP diet (P < 0.05). Longissimus muscle area and fat measurements were unaffected by betaine or dietary protein on d 28. However, by d 56 betaine reduced average fat depth in barrows (P < 0.05; 3.21 vs 3.40 cm), but not in gilts. Betaine may be more effective at altering body composition in barrows than in gilts.     

Value of raw soybeans and soybean oil supplementation in sow gestation and lactation diets: a cooperative study

A cooperative study using 215 sows during two parities (349 litters) was conducted at six stations to determine the effect of raw soybeans in gestation and lactation diets on sow and litter performance. Sows were bred and allotted to fortified corn diets containing either soybean meal (control) or raw soybeans. A corn-soybean meal-soybean oil diet, isocaloric to the raw soybean diet, was included as a third treatment at three stations. All diets contained 14% CP. These diets were fed during both gestation and lactation through two parities. The daily gestation feed intake ranged from 1.8 to 2.3 kg/sow, depending on station. During lactation, the sows were allowed ad libitum access to their respective diets. Gestational weight gain was not influenced by diet, but sows fed raw soybeans consumed less (P less than .01) feed during lactation and had greater (P less than .01) lactational weight loss and their pigs were lighter in weight (P less than .05) both at 21 d and at weaning (varied between 3 and 5 wk of age). Sows fed the diet with supplemental oil had reproductive and lactational performance similar to those fed the control diet. Milk obtained at d 10 to 14 of lactation from sows fed raw soybeans had lower (P less than .05) protein content than milk from sows fed the other two diets, but fat content of the milk tended to be increased by raw soybeans or by added soybean oil. Return to estrus was not affected by diet.(ABSTRACT TRUNCATED AT 250 WORDS)     

Raw soybeans for gestating swine

An experiment was conducted to determine the influence of feeding ground raw soybeans to swine during gestation on reproductive performance for three consecutive parities. Sixty crossbred gilts were bred and randomly assigned to two dietary treatments with 30 gilts/treatment. The diets were formulated to contain 14% crude protein with either soybean meal (SBM) or raw soybeans (RSB) serving as the source of supplemental protein. All animals were fed in individual gestation stalls and were given 1.81 kg of feed/d. Upon entering the farrowing house at approximately 110 d of gestation, all animals, regardless of previous treatment, were fed the same lactation diet (15% protein corn-soybean meal diet) until the pigs were weaned (28 d). After completing three parities, 88 of a possible 90 litters were farrowed by each dietary group. Total number of live pigs at parturition and 21 d for three parities were: (SBM) 887, 732 and (RSB) 924, 765, respectively. Average pig birth and 21-d weights for each dietary group were (SBM) 1.52, 5.42 and (RSB) 1.59, 5.41 kg, respectively. Pigs from dams fed RSB had higher average pig birth weights (P less than .05), but weaning weights were not affected. There were no significant differences in maternal weight changes during gestation. Milk samples were collected within 6 h after parturition, 3 and 14 d of lactation. Percentage milk fat for each time period was: (SBM) 5.6, 9.0, 7.0 and (RSB) 6.3, 10.7, 6.5, respectively. Sows fed RSB had a higher milk fat at 3 d (P less than .05) but a lower milk fat at 14 d (P less than .1) than did the sows fed SBM. The study indicated RSB can be effectively utilized in gestation diets fed to swine.     

Long-term, but not short-term, treatment with somatotropin during pregnancy in underfed pigs increases the body size of progeny at birth

Treatment of pigs with porcine ST (pST) in early to mid-pregnancy increases body weight and length of their fetuses by mid-pregnancy, but this increased weight may not persist to birth. We investigated the effects of short- (25 d) and long-term (75 d) treatment with pST, and interactions between long-term pST treatment and crude protein content of diet, in restricted-fed gilts. In both experiments, Large White x Landrace gilts were bred at first estrus to Large White x Duroc boars and allowed to farrow naturally. In the first experiment, gilts were fed 1.8 kg/d of a diet containing 13.5 MJ DE/kg of DM and 15.05% CP (as-fed basis) throughout pregnancy, and were injected daily with 0, 2, or 4 mg pST from d 25 to 50 of pregnancy. Maternal treatment with pST from d 25 to 50 of pregnancy did not affect the number of piglets born per litter or progeny size at birth. In the second experiment, gilts were injected daily with 0 or 2 mg of pST and fed 2.2 kg/d of a diet containing 14.5 MJ DE/kg and either (as-fed basis) 16.6% (0.81% lysine) or 22.2% CP (1.16% lysine) from d 25 to 100 of pregnancy. All gilts were then fed 3.0 kg/d of the lower protein diet from d 100 of pregnancy to farrowing. Treatment with 2 mg pST/d from d 25 to 100 of pregnancy increased live weight of all gilts during the treatment period (P = 0.016), but the change in maternal live weight from d 25 to 100 of pregnancy was only increased (P = 0.001) by pST in gilts fed the higher protein diet. Live weight of gilts 1 d after farrowing was increased by pST treatment (P = 0.007), but was not altered by protein content of diet during pregnancy. In gilts fed the lower protein diet, but not in those fed the higher protein diet, pST treatment decreased maternal backfat depth during treatment (P < 0.020) and 1 d after farrowing (P = 0.002). Treatment with pST during pregnancy did not affect the number of piglets born per litter but independently increased body weight by 11.6% (P < 0.001) and length by 3.4% (P = 0.005) of progeny at birth and decreased (P < 0.01) the negative effect of litter size on body weight at birth. We conclude that in feed-restricted gilts, fetal weight gains in response to 25 d of pST treatment before mid-pregnancy are not maintained to term but that treatment with pST during most of pregnancy increases progeny size at birth and reduces maternal constraint of fetal growth.     

Effect of postnatal nutritional status on subsequent growth and reproductive performance of gilts

Two trials involving 128 gilts were conducted to determine the effect of nutritional status during the first 28 d postnatally on subsequent growth and reproductive performance. Nutritional status was altered by adjusting litter size at birth to either 6 or 12 pigs and maintaining a lactation length of either 13 or 28 d. Pigs weaned at d 13 were fed on an ad libitum basis or at 50% of ad libitum through d 28. After d 28, all pigs were fed the same diets through the first parity. By market weight (d 154) pigs recovered differences in body weight imposed during the early postnatal period. Postnatal nutritional status did not alter age at puberty. Gilts weaned at d 28 from litter size 6 produced 2.4 more (P less than .05) ova than gilts from litter size 12; however, when weaned at d 13, gilts from litter size 6 produced 2.3 fewer ova than gilts from litter size 12. Feed restriction for 15 d postweaning did not depress ovulation rate in gilts. Subsequent litter size was not affected by postnatal litter size, lactation length or feed restriction, even though growth rate and ovulation rate had been altered by treatments imposed during the first 28 d postnatally. Assuming no difference in fertilization, these data suggest that prenatal mortality was altered by the early postnatal treatments and was the limiting factor for litter size. Until factors that influence prenatal losses are characterized and controlled, the alteration of nutritional status by changes in postnatal litter size, lactation length or feeding level will not detrimentally affect subsequent litter size in gilts.     

Influence of protein intake, energy intake and stage of gestation on growth, reproductive performance, nitrogen balance and carcass composition in gestating gilts

Thirty-six crossbred gilts were fed three levels of protein (146, 255 and 364 g/d) and two levels of energy (6,200 and 7,440 kcal of digestible energy/d) throughout gestation in a 3 x 2 factorial arrangement of treatments. Five-day N balance studies were conducted in early (0 to 30 d), mid- (30 to 60 d) and late (60 to 90 d) gestation. At slaughter (90 d of gestation), reproductive tracts were weighed and evaluated for reproductive performance and samples of the reproductive tract, liver and semimembranosus muscle (SM) were analyzed for crude protein. The right half of the carcass was subjected to a physical separation of fat, lean and bone. Neither dietary protein nor energy level significantly affected weight gain or reproductive performance. Nitrogen retention increased as dietary protein level increased and stage of gestation progressed (linear effect, P less than .01), but efficiency of N utilization and dry matter digestibility decreased with increasing protein intakes (quadratic effect, P less than .05 and linear effect, P less than .01, respectively). Nitrogen retention (P less than .01), efficiency of N retention (P less than .05) and dry matter digestibility (P less than .01) were higher in gilts fed high (H) energy compared with gilts receiving moderate (M) energy diets. Increasing dietary protein increased total carcass separable lean tissue (quadratic effect, P less than .01), liver weight (linear effect P less than .01) SM weight (quadratic effect, P less than .05) and SM percentage M (linear effect P less than .10). Similarly, total carcass N and carcass lean N increased as protein level increased (quadratic effect, P less than .10, P less than .05, respectively). In contrast to the increase in muscle N, N in uterine tissue and fluids was not affected by dietary protein level. The results of this experiment suggest that 146 g of crude protein/d during gestation is just as effective as higher levels of crude protein for litter size or storage of N in reproductive tissue, but 255 to 364 g of protein/d are required to maximize muscle N.     

Effect of lasalocid on reproductive performance and subsequent lactation in the sow

The effect of lasalocid (140 mg . head-1 . d-1) on sow reproductive performance and subsequent piglet performance during lactation were examined in a trial that involved 114 sows. Treatments consisted of 1) control diet with no lasalocid during gestation and lactation; 2) lasalocid diet during gestation, control diet during lactation; 3) control diet during gestation and lasalocid diet during lactation; and 4) lasalocid diet during gestation and lactation. The addition of lasalocid either to gestation or lactation diets had no effect (P greater than .10) on sow weight gains or days to return to estrus postweaning. Milk protein percentages were similar (P greater than .10) for sows in all treatment groups for samples taken at 3, 7 and 14 d postfarrowing. Milk fat percentages were higher (P less than .05) in fall-bred sows at d 3 for Treatments 1, 3 and 4 than for Treatment 2 No significant differences (P less than .10) were observed for litter size at birth, 21 d postfarrowing or at weaning. Piglet weights at birth, 21 d and weaning were similar (P less than .10) among treatment groups. However, litter size and litter weight gains tended to be heavier at 21 d postfarrowing and at weaning for fall-bred sows fed lasalocid in either gestation and (or) lactation compared with those fed the control diet.     

The influence of premating feed intake on the reproductive performance of gilts.

In an attempt to improve the reproductive performance of gilts mated at puberty, 70 Yorkshire x Landrace gilts were allocated at 120 d of age and 60 kg body weight to one of two treatments. Restricted gilts were fed 2.0 kg d-1 of a diet formulated to provide 18% crude protein and 14.5 MJ DE kg-1 from selection until mated at their first estrus (n = 35). Flushed gilts were fed 2.0 kg d-1 of the same diet from 120 to 150 d of age, but then had their feed intake increased to 3.5 kg d-1 until mated at their first estrus (n = 35). An additional group of gilts (control fed; n = 33) were fed 3.0 kg d-1 from selection until they were bred at their third estrus in order to investigate the influence of feed restriction on the onset of puberty. During gestation all gilts were fed 1.8 to 2.2 kg d-1 of a 16.8% crude protein diet having 13.7 MJ DE kg-1. Control fed gilts were younger (p less than 0.05) at puberty (150 d) than restricted (165 d) or flushed gilts (165 d). There was no difference in subsequent litter size between the restricted and flushed gilts (7.7 and 8.0, respectively). It is concluded that the institution of a flushing nutritional regime in the prepubertal period will not enhance piglet production from gilts mated at puberty.     

Excess crude protein for nongravid gilts

Twenty-five nongravid crossbred gilts (avg initial wt, 126 kg) were placed on either a high (38%) or a low (13%) crude protein (CP) diet and fed either at the rate of 1.82 kg/d or had ad libitum access to feed. In addition, a fifth group was pair-fed the 13% CP diet to the average intake of the gilts fed high CP ad libitum. The experimental period lasted 30 d. Corn-soybean meal diets were used and CP levels were varied by altering the corn:soybean meal ratio. Gain and gain/feed were reduced (P less than .01) in gilts fed 1.82 kg/d compared with the gilts fed ad libitum or pair-fed gilts. Gain (P less than .03) and feed intake (P less than .01) of gilts with ad libitum access to the 13% CP diet were higher than those of gilts with ad libitum access to the 38% CP diet. Gain/feed was not different (P greater than .10) between the two groups, however. Rate of gain and feed efficiency of gilts pair-fed the 13% CP diet were similar (P greater than .10) to those of gilts with ad libitum access to the 38% CP diet. Plasma total free amino acids, NH3 and total protein were not (P greater than .10) affected by treatment. Plasma urea-N and urinary total N, urea-N and orotic acid were increased (P less than .01) in gilts fed the high CP diet regardless of feed intake level. However, urinary NH3 was higher (P less than .01) in gilts fed the low-protein diet. These results indicate that excess dietary CP for nongravid gilts decreases gain and feed intake and has no effect on efficiency of feed utilization, but it increases plasma urea-N and urinary total N, urea-N and orotic acid.     

Effects of supplemental biotin during gestation and lactation on reproductive performance of sows: a cooperative study

A cooperative experiment to evaluate biotin addition to sow diets was conducted at three research stations using 303 litters. Primiparous and multiparous sows (overall average parity 2.8) were fed a 14% CP corn-soybean meal diet (140 micrograms/kg biotin), with or without supplemental biotin (330 micrograms added biotin per kg feed), throughout gestation and lactation. As many sows as possible were fed their respective diets through three successive parities. During gestation, sows were given from 1.82 to 2.27 kg of feed per day, depending on environmental conditions; during lactation sows had ad libitum access to feed. Supplemental biotin had no effect (P greater than .35) on sow weights at breeding, at d 109 of gestation, at farrowing or at weaning. No differences were found in litter size at birth (P greater than .18), but at d 21 of lactation, sows fed the diet containing supplemental biotin had larger litters than sows fed the unsupplemented diet (9.4 vs 8.7 pigs, respectively; P = .01). Pig weights at birth and d 21 of lactation were not affected (P greater than .20) by dietary treatment. Biotin supplementation did not affect (P greater than .28) the length of the interval from weaning to estrus. No evidence was found that feet cracks or bruises were reduced by biotin supplementation. The results indicate that biotin supplementation of a corn-soybean meal diet during gestation and lactation increased the number of pigs at d 21 of lactation, but it did not decrease the incidence of foot lesions.     

Long-term effects of boron supplementation on reproductive characteristics and bone mechanical properties in gilts

An experiment was conducted to determine long-term effects of dietary boron (B) on reproductive and bone characteristics in gilts. Weanling gilts (n = 50) were allotted to 10 pens based on weaning weight and litter origin. Pens were randomly assigned to receive one of two dietary treatments that consisted of a basal diet low in B (control) and the basal diet supplemented with 5 mg of B/kg diet as sodium borate. Gilts remained on their respective experimental diets throughout the nursery phase, growing-finishing phase, sexual maturity, breeding, gestation, and lactation. The day of first observed standing estrus was defined as puberty, and each pubertal gilt was bred via AI at the second observed standing estrus. Eight randomly selected gilts per treatment were slaughtered at d 35 of gestation for the assessment of embryonic and reproductive characteristics, bone characteristics, and tissue B concentrations. The remaining pregnant gilts (control, n = 11; 5 mg supplemental B/kg diet, n = 10) farrowed, and litter characteristics at farrowing and weaning were determined. Age at puberty was not affected (P = 0.72) by B, and neither were the number of corpora lutea on the ovaries (P = 0.44) or the total number of embryos (P = 0.95) at d 35 of gestation. Boron supplementation increased (P = 0.05) pig weaning weight and tended (P = 0.11) to increase pig birth weight; however, no other litter characteristics were affected (P > 0.12) by B. Extrinsic and intrinsic strength measures of bone were increased (P < 0.09) by B. Fat-free bone ash percentage and bone mineral concentrations were not affected (P > or = 0.19) by dietary B. Supplemental B increased (P < or = 0.06) the B concentrations of the muscle, liver, and reproductive tissues. Serum osteocalcin concentrations tended (P = 0.13) to be increased by dietary B, which may be related to increased bone turnover in B-supplemented gilts. Results indicate that B may have beneficial effects upon reproductive and bone characteristics.     

Supplemental biotin for swine. II. Influence of supplementation to corn- and wheat-based diets on reproductive performance and various biochemical criteria of sows during four parities

Data from 116 females previously fed a corn-soybean basal diet with 0 or 220 micrograms supplemental biotin/kg during growth and development were used to study the influence of 0 (NB) or 440 (SB) micrograms of supplemental biotin/kg to corn-(C) or wheat-(W) based diets for gilts and sows housed in total confinement. Reproductive performance through four parities (total of 245 litters) and various sow and pig biochemical criteria were evaluated. Females fed W diets were older (P less than .07) at first estrus, farrowed litters that were lighter weight (P less than .01) at birth and that contained fewer (P less than .05) total and live pigs compared with females fed C diets. Biotin supplementation did not significantly influence (P greater than .10) farrowing and lactation performance; however, after the first parity, total and live pigs/litter at farrowing tended to be larger for SB females. Conception rate at first estrus postpartum was increased (P less than .07) by 9% and the average weaning to estrus interval was reduced (P less than .05) from 14.5 to 10.2 d with SB. Biotin supplementation increased (P less than .001) the biotin content of sow plasma, milk and liver, while sow liver pyruvate carboxylase activity was not altered (P greater than .10). Pigs farrowed by SB females had three- and fivefold higher (P less than .001) levels of plasma biotin at birth and 14 d of age, respectively; however, liver biotin levels at birth were not different (P greater than .10) for pigs from NB and SB females.(ABSTRACT TRUNCATED AT 250 WORDS)     

Justification of unilateral hysterectomy-ovariectomy as a model to evaluate uterine capacity in swine

Experimental objectives were to measure the effect of ovulation rate on litter size at 86 d of gestation and at farrowing in 110 unilaterally hysterectomized-ovariectomized (UHO) gilts and in 142 intact, control gilts and to evaluate postnatal survival and development of progeny. Surgery (UHO) was performed on gilts 8 to 12 d following first estrus. Control and UHO gilts were mated and then randomly assigned to be slaughtered at d 86 of gestation or allowed to farrow. Gilts scheduled to farrow were observed by laparoscopy on d 40 of gestation to count corpora lutea (CL). Ovulation rate (number of CL) was similar for control (12.1 CL) and UHO (11.9 CL) gilts, thus indicating that compensatory ovarian hypertrophy had occurred in UHO gilts and resulted in a near doubling of ova per uterine horn relative to control gilts. Average litter size at 86 d of gestation and farrowing was greater (P less than .01) for control than UHO gilts. At farrowing, litter size for control and UHO gilts was 9.0 +/- .3 and 5.7 +/- .3 pigs, respectively. Fetal losses were greater and pig weights at birth were less in litters by UHO gilts. Postnatal pig survival, growth rate to 14 d of age and 14-d individual pig weight did not differ for progeny of control and UHO gilts, and performance of UHO pogeny did not appear to compromise the usefulness of this animal model. Regression of litter size on ovulation rate was .41 +/- .15 pigs/CL for UHO and .60 +/- .12 pigs/CL for control gilts at d 86 of gestation. Regression was .07 +/- .17 pigs/CL for UHO and .42 +/- .14 pigs/CL for control gilts at farrowing.(ABSTRACT TRUNCATED AT 250 WORDS)