Survival and postweaning performance of pigs from sows fed fat during late gestation and lactation

Sows were fed a control corn-soybean meal gestation diet to d 80 of gestation. One group of sows (n = 25) continued receiving the control diet until the end of lactation, whereas two groups were placed on other treatments. One group (n = 27) was fed a diet containing 5% added solid fat pellets from gestation d 80 through lactation, whereas another group (n = 25) was fed a diet with 10% added solid fat pellet from gestation d 100 through d 14 of lactation. Feed supply was 2.27 kg/d during gestation and to appetite during lactation. Pigs from sows fed the control diet or 5% solid fat pellet diet were weaned with an age range of 22 to 28 d and immediately allotted in a 2 x 3 factorially designed 4-wk feeding trial. Pigs from these two sow groups were fed diets 1) without fat, 2) with 4.5% choice white grease or 3) with 5% solid fat pellet. Sow weight loss, backfat change and pig weights were not different at weaning among treatments. Survival rates of all pigs to 21 d averaged 90% with no significant differences between treatments. Pigs from fat-fed sows had more (P less than .05) glycogen per gram of liver, 41% more total liver glycogen and 16% more serum glucose at birth. Weanling pigs from fat-fed sows grew slower (P less than .05) than pigs from control sows. Supplemental fat during gestation increased liver glycogen of pigs, which should help survival, but the feeding of fat throughout lactation had a negative effect on ADG during a 4-wk postweaning period.     

Effects of dietary additions of fat and triamcinolone for sows during late gestation on subsequent pig performance

Three trials involving 118 sows were conducted to evaluate the effects of fat and triamcinolone additions in the diets of late-term gravid sows on pre- and postweaning performance of pigs. Beginning an average of 9 d prepartum, sows were fed daily 1.8 kg of a fortified, corn-soybean meal diet [6 Mcal of metabolizable energy (ME) and 290 g of protein/sow] that was supplemented with 4 Mcal of ME/sow in the form of starch, soybean oil or soybean oil plus 70 mg/sow of triamcinolone, a synthetic glucocorticoid. During a 28-d lactation, sows were self-fed a standard 14% protein, corn-soybean meal diet. The addition of soybean oil to the diet of sows during late gestation did not (P greater than .10) influence the weights of survivability of pigs at birth, 14 or 28 d of age, but increased (P less than .05) the carcass fat content of the pigs at birth. The dietary addition of triamcinolone to the sow's prepartum diet increased (P less than .10) pig weights at birth and 14 d, and tended to increase pig weights at 28 d compared with those of pigs from sows fed soybean oil only. Prepartal administration of triamcinolone depressed (P less than .05) carcass protein content and adrenal weights in pigs at birth or 28 d of age. From weaning (d 28) to 56 d of age, pigs from sows fed soybean oil before parturition, particularly those from sows fed triamcinolone, tended to consume less feed and gained slower and less efficiently than pigs from sows fed starch, although the differences were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of genetic line and supplemental dietary fat on lactation performance of Duroc and Landrace sows.

A total of 124 Duroc and 99 Landrace primiparous and multiparous sows were assigned, within breed and contemporary group, to control (N) or 10% added fat (F) diets on d 105 of gestation based on parity and genetic line (control or selected for improved sow productivity), to determine the effects of genetic line and fat addition to the lactation diet on sow and litter performance. Weekly feed intake was not affected (P greater than .10) by genetic line for Duroc and Landrace sows but feed intake was reduced (P = .08) during wk 1 to 4 for Duroc sows and during wk 1 and 4 for Landrace sows (P less than .05) when they were fed diet F compared with diet N. Select (S)-line Duroc and Landrace sows lost more weight during lactation (P less than .01) than did control (C)-line sows. Select-line Landrace sows lost more backfat during lactation (P less than .05) than did C-line sows. Landrace sows lost less weight during lactation (P less than .05) when fed diet F than when fed diet N. The total number of pigs born, born alive, and alive at 21 d and at weaning were higher (P less than .01) for S-line Duroc sows, and litter size at 21 d and at weaning was higher (P less than .01) for S-line Landrace sows than for C-line litters within each breed. Pig survival from birth to weaning was increased (P = .07) for Duroc sows fed diet F but not for Landrace sows.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of gestation energy level on the production of Large White x Landrace sows

Sixty-four Large White x Landrace primiparous sows were utilized to evaluate the influence of feeding 6 vs 9 Mcal ME/d during gestation on reproductive performance. The sows remained on their respective gestation diets for four parities if they successfully farrowed, rebred and conceived. Sows fed 9 Mcal ME/d gained more weight (P less than .05) through the gestation period during parities 1 and 2 and were heavier (P less than .01) on d 110 of gestation for combined parities. Lactation weight loss was greater (P less than .05) for the sows fed 9 Mcal ME/d, resulting in similar weights at weaning. Ultrasonic backfat measurements were greater (P less than .01) on d 110 of gestation for sows fed 9 Mcal ME/d during parity 1 and remained higher (P less than .01) through the fourth-parity gestation. Although sow weaning weights were similar, sows receiving 6 Mcal ME/d scanned less backfat thickness. Gestation treatment significantly affected consumption of a common lactation diet provided ad libitum. Sows fed 6 Mcal ME/d during gestation consumed an average of 22 kg more feed (P less than .01) during lactation than those sows receiving 9 Mcal ME/d. Litter performance as measured by number and weights of pigs born alive and weaned was not altered (P greater than .10) by gestation energy intake. Days to return to estrus and the number of sows remaining in the study for four parities were similar (P greater than .10) between the two treatment groups. The number of farrowings for the four parities totaled 164, with 83 and 81 farrowings for the sows fed 6 and 9 Mcal ME/d, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of feeding sows fat or fructose during late gestation and lactation

The effects of dietary fat or fructose supplementation during late gestation and lactation on sow milk production and composition and on progeny were examined. On d 88 of gestation, 24 sows were allotted by parity to three dietary treatments (eight sows/treatment). Treatments were 1) a 12.5% crude protein, corn-soybean meal control, 2) the control + 10% added fat or 3) the control + 23% high fructose corn syrup. All treatments were fed to supply 1.82 kg/d of the control diet from d 89 of gestation to parturition with sows in treatments 2 or 3 receiving .18 kg of additional fat or .53 kg of additional high fructose corn syrup, respectively. Feed was gradually increased from d 1 to 7 of lactation to 4.54 kg/d of the control diet (plus .45 kg of added fat and 1.33 kg of added fructose for treatments 2 and 3) and remained at these levels for the remainder of the 21 d lactation period. All treatments were iso-nitrogenous; treatments 2 and 3 were iso-caloric. Litter birth weights, number of pigs born alive, weaning weights and piglet survival rate were not affected by sow treatment. Stillbirths were less (P less than .05) for sows fed fat. Lipid content of milk 24 h post-farrowing was greater (P less than .05) from sows fed fat compared with sows fed fructose. Milk production estimates indicated that multiparous sows fed fat produced more (P less .05) milk than sows fed the control diet. On d 112 of gestation and d 15 of lactation, serial blood samples were drawn to monitor sow response to a glucose challenge (1 g/kg body weight).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of lactation and rebreeding phase energy intake on primiparous and multiparous sow performance

Fifty-three primiparous sows were used to study the effects of a high-energy, fat-supplemented diet on sow lactation and rebreeding performance. Sows received either a low [Lo, 12.5 Mcal metabolizable energy (ME)/d] or high (Hi, 16.0 Mcal ME/d) energy sorghum-soybean diet during a 28-d lactation. At weaning, sows were randomly allotted, within lactation treatment, to a low (lo, 5.54 Mcal ME/d) or high (hi, 9.61 Mcal ME/d) energy sorghum-soybean diet until the day of first postweaning estrus. Primiparous sows fed Lo weaned larger (P less than .05) litters than sows fed Hi; however, average pig weight was not affected by lactation treatments. Primiparous sows fed Hi had more backfat at weaning (P less than .01) than Lo sows. In contrast, sow weight was not affected by dietary treatments. Neither lactation nor rebreeding treatments influenced days to rebreeding; however, an interaction (P less than .01) was observed. Mean days from weaning to rebreeding for Lolo, Lohi, Hilo and Hihi sows were 10.0, 7.6, 6.9 and 17.1, respectively. Forty sows were maintained on the same dietary treatments during their second parity. Sows receiving Lo during their second parity farrowed and weaned more (P less than .05) pigs than Hi sows. Multiparous sows fed Hi nursed heavier (P less than .05) pigs on d 21 of lactation and at weaning compared with Lo sows. Sows fed Hi were heavier (P less than .05) and had more (P less than .01) backfat at weaning of their second litter compared to Lo sows. Days to postweaning estrus were not affected by lactation or rebreeding diets. Mean length of the second parity rebreeding interval for Lolo, Lohi, Hilo and Hihi sows was 6.2, 10.2, 7.0 and 10.5 d, respectively. These results suggest that feeding levels during lactation of 12.5 Mcal ME/d or higher supported adequate rebreeding performance. Postweaning feeding levels did not influence days to first estrus. Feeding a high energy diet continuously throughout the lactation and rebreeding phases in primiparous sows may lengthen the postweaning interval to estrus.     

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.     

Effect of feather meal as a source of valine for lactating sows

An experiment was conducted to evaluate feather meal as a source of Val in lactating sow diets. Sows (five farrowing groups; mean parity = 2.34) were allotted to one of two dietary treatments on the basis of ancestry, parity, and weight and date of d 110 of gestation. The treatment diets included 1) corn-soybean meal lactation diet (n = 40) or 2) corn-soybean meal lactation diet with 2.5% feather meal (n = 39). The diets were formulated on an equal Lys basis. All litters were adjusted to 10 pigs within 24 h after farrowing, and all sows weaned at least nine pigs. Sows were bled at 110 d of gestation and at weaning, and serum urea N was determined. Backfat thickness was determined ultrasonically at 110 d of gestation and at weaning. Serum urea N and backfat thickness at d 110 of gestation were used as covariates for serum urea N and backfat thickness at weaning, respectively. The litter response criteria (weaning weight, litter weight gain, and percentage survival) were not affected (P > .10) by feather meal. The sow response criteria (weaning weight, weight loss per day, weaning backfat thickness, change in backfat thickness, ADFI, and days to estrus) were not affected (P > .10) by feather meal. Sows fed feather meal had increased (P < .01) serum urea N and tended (P = .15) to have decreased sow weaning weight. Following the initial analysis of the data, the data set was split into two groups: 1) sows with litters gaining less than 2.17 kg/d (n = 19 and 20 for control and feather meal diets, respectively) and 2) sows with litters gaining more than 2.17 kg/d (n = 21 and 19 for control and feather meal diets, respectively). These two groups were analyzed separately. In sows with litters gaining less than 2.17 kg/d, the litter and sow criteria were not affected (P > .10) by treatment. In sows with litters gaining more than 2.17 kg/d, sow weaning weight was decreased (P < .04) and sow weight loss (P < .02) and serum urea N (P < .01) were increased in sows fed feather meal. Feather meal (as a source of Val) did not improve litter weight gain, but it increased serum urea N.     

Effect of dietary energy intake during lactation on performance of primiparous sows and their litters

A total of 146 primiparous sows was used in four replications of an experiment to investigate the effect of energy intake during a 28-d lactation on sow and litter performance. Dietary treatments consisted of three energy intakes; 10, 12 or 14 Mcal of metabolizable energy (ME) X sow-1 X d-1. All sows were fed equal amounts of crude protein, vitamins and minerals daily, which met or exceeded standard recommendations. The experiment was initiated at parturition. Sow weight and backfat loss during lactation decreased linearly (P less than .001) as energy intake increased. There were no differences in litter size at either 14 d of lactation or weaning. Pig weights on d 14 increased linearly (P less than .05) and litter weights tended to increase linearly (P = .13) as energy intake increased. At weaning, pig weights and litter weights increased (P less than .05) as sow energy intake increased. There were no significant differences in the percentages of sows in estrus by 7, 14, 21 and 70 d postweaning, but sows fed 10 Mcal ME/d had a slightly longer interval from weaning to first estrus than sows fed higher energy intakes. Serum urea concentrations of sows were inversely related to energy intake during lactation. Serum creatinine concentrations were not affected by energy intake. An intake of 10 Mcal ME/d by primiparous sows during a 28-d lactation resulted in reduced sow and litter performance; there was little difference between sows fed 12 and 14 Mcal ME/d.     

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)     

Dietary medium- or long-chain triglycerides improve body condition of lean-genotype sows and increase suckling pig growth

In a field trial conducted on a commercial swine farm, lean-genotype sows (n = 485) were fed diets containing 0 or 10% supplemental fat as either medium-chain triglyceride or choice white grease from d 90 of gestation until weaning (15.5 d). Effects on standard sow and litter production traits were examined together with assessment of sow body condition using live ultrasound. Daily feed intake during lactation was 10% higher in sows consuming diets without added fat (7.2 vs 6.5 kg; P < 0.01); however, lactation ME (23.9 Mcal/d) and digestible lysine (54 g/d) intakes were unaffected (P > 0.10). Sows supplemented with fat were 4 kg heavier on d 109 of gestation (220 vs 224 kg; P < or = 0.01), 1 d after farrowing (210 vs 214 kg; P < or = 0.01), and at weaning (210 vs 214 kg; P < or = 0.01). Expressed as overall gain, this amounted to a 23% increase (0.66 vs 0.86 kg/d; P < or = 0.01) and was accompanied by a 49% increase in backfat (0.82 vs 1.68 mm; P < or = 0.03) from d 90 to farrowing. Changes in sow weight (-0.01 kg/d) and backfat (+4.2 mm) over lactation were minimal and were not affected by fat supplementation (P > or = 0.10). Longissimus muscle area at weaning was slightly greater (44.96 vs 46.2 cm2) in sows consuming fat than in control sows (P < or = 0.05), but changes in longissimus muscle area were not significant from d 90 to weaning (P > or = 0.10). Gestation length, pigs born alive, average birth weight, survival (d 3 to weaning), and days to estrus were not affected by diet (P > 0.10). However, supplemental fat increased pig ADG (192 vs 203 g/d; P < 0.01) and average pig weaning weight (4.3 vs 4.5 kg) at 15.5 d (P < or = 0.02). No differences between the two fat sources were detected. This large-scale study demonstrated that supplemental fat during gestation and lactation effectively improved sow condition and improved suckling pig performance without affecting energy intake during lactation, implying improved efficiency of sow energy utilization.     

The addition of ground wheat straw as a fiber source in the gestation diet of sows and the effect on sow and litter performance for three successive parities

A regional experiment was conducted at 8 experiment stations, with a total of 320 sows initially, to evaluate the efficacy of adding 13.35% ground wheat straw to a corn-soybean meal gestation diet for 3 successive gestation-lactation (reproductive) cycles compared with sows fed a control diet without straw. A total of 708 litters were farrowed over 3 reproductive cycles. The basal gestation diet intake averaged 1.95 kg daily for both treatments, plus 0.30 kg of straw daily for sows fed the diet containing ground wheat straw (total intake of 2.25 kg/d). During lactation, all sows on both gestation treatments were fed ad libitum the standard lactation diet used at each station. Response criteria were sow farrowing and rebreeding percentages, culling factors and culling rate, weaning-to-estrus interval, sow BW and backfat measurements at several time points, and litter size and total litter weight at birth and weaning. Averaged over 3 reproductive cycles, sows fed the diet containing wheat straw farrowed and weaned 0.51 more pigs per litter (P 相似文献   

Effect of dietary supplementation of oregano essential oils to sows on colostrum and milk composition, growth pattern and immune status of suckling pigs

This study evaluated the effects of supplementing sow diets with oregano essential oils (OEO) during gestation and lactation on sow colostrum and milk composition and on the growth pattern and immune status of suckling pigs. A total of 70 second-parity sows were randomly assigned to 1 of 2 gestation dietary treatments within 24 h after service: control (CON) or CON + 250 mg/kg of OEO (OREG). In lactation, sows were again assigned to either the CON or OREG dietary treatment. Thus, the lactation treatments were CON-CON, CON-OREG, OREG-CON, and OREG-OREG. Colostrum and blood samples were collected from 6 sows per lactation dietary treatment. Thymus lymphocyte (T lymphocyte) subpopulations (γδ, cluster of differentiation 8, and 32 cluster of differentiation 4) were enumerated in blood and mammary secretions along with IGF-1, IgG, and IgA concentrations. Piglet growth rate were determined from 18, 17, 17, and 18 litters from the CON-CON, CON-OREG, OREG-CON, and OREG-OREG lactation dietary treatments, respectively. Growth rates were determined in 630 piglets, and piglets were individually identified and weighed on 1, 5, 9, 12, 16, and 19 d of age. Oregano essential oil supplementation during gestation or lactation had no effect (P > 0.05) on GE, CP, GE:CP, GE:fat, and IGF-1 in sow milk. Reductions of the fat percentage in milk on d 7 (P < 0.05) and d 14 (P = 0.07) were found in sows supplemented with OEO during lactation compared with those in the CON treatment. Milk from sows supplemented with OEO during lactation had the greatest number of T lymphocytes compared with those in the lactation CON treatment on d 14 of lactation (P < 0.01). The number of T lymphocytes in milk was greater for sows in the CON-OREG treatment compared with those other treatments on d 14 of lactation (P < 0.05). Energy intake was greater on d 1 to 5 in piglets from sows fed OEO during gestation than those from sows in the CON treatment (P < 0.05). A trend (P = 0.10) for greater milk intake was observed in piglets from sows supplemented with OEO during gestation compared with those from sows in the CON treatment. Similarly, a tendency for an increase in ADG on d 1 to 5 was found in piglets from sows supplemented with OEO during gestation compared with those from sows in the CON treatment (P = 0.10). Insulin-like growth factor-1 at birth and on d 7 and 14 of lactation did not differ among piglets from sows assigned to the different dietary treatments. Oregano essential oil supplementation of sow diets did not affect (P > 0.05) immunoglobulin concentrations in piglets after suckling. Supplementing sow diets with OEO during gestation or lactation did not affect (P > 0.05) the T lymphocytes, percentage of T-lymphocyte subpopulations, and natural killer cell activity of piglets during lactation. Supplementing sow diets with 250 mg/kg of OEO during gestation and lactation did not affect the growth potential of and immune responses in suckling piglets.     

Recombinant porcine somatotropin for sows during late gestation and throughout lactation.

Two experiments were conducted to evaluate whether administration of recombinant porcine somatotropin (pST) to sows (Hampshire-Yorkshire) enhanced lactational performance. In Exp. 1, sows (n = 84) were fed a corn-soybean meal diet (17.8% CP), or a similar diet with 8% added fat, from d 108 of gestation to d 28 of lactation. Half of the sows fed each diet were injected with 6 mg/d of pST from d 108 of gestation to d 24 of lactation. Diets were fed at 2.27 kg/d from d 108 of gestation until farrowing and then were self-fed during lactation. By d 3 of lactation, litter size was standardized at 8 to 10 pigs per litter. Treating sows with pST resulted in a 10-fold increase (P less than .001) in serum somatotropin at 4 h postinjection. Serum glucose was increased (P less than .01) and serum triglycerides, creatinine, and urea N were decreased (P less than .01) by pST. During the summer, apparent heat stress occurred in pST-treated sows, resulting in 14 deaths. Most (10) of the deaths occurred just before, during, or shortly after farrowing. Fewer (P less than .08) deaths occurred when pST-treated sows were fed the diet with added fat. Sows treated with pST consumed less feed (P less than .10) and lost more backfat (P less than .10) during lactation than controls. Increasing the dietary fat did not prevent these changes. Weaning weights of pigs and milk yield of sows (estimated by deuterium oxide dilution) were not affected by pST treatment. In Exp. 2, sows (n = 42) were injected weekly with 0 or 70 mg of pST on d 3, 10, 17, and 24 of lactation. Litters were standardized by d 3 at 8 to 10 pigs, and sows were fed the same control (low fat) diet as in Exp. 1. Sows treated with pST consumed less feed and lost more weight and backfat during lactation than untreated sows. Litter size, average pig weaning weights, and milk yield were not influenced by pST treatment. These data indicate that a 6-mg daily injection of pST from 6 d prepartum to d 24 of lactation or a 70-mg weekly injection of pST from 3 d postpartum to d 24 of lactation does not increase milk production in lactating sows.     

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.     

Effect of feeding thyrotropin-releasing hormone to lactating sows

Two experiments were conducted to assess the effects of feeding thyrotropin-releasing hormone (TRH) during lactation on sows. In Exp. 1, sows were fed 0, 1, 10, 100 or 1,000 mg TRH on d 10.8 +/- .4 (mean +/- SE) after parturition. Blood samples were taken from sows every 30 min from -2 h to 8 h and at 10, 12 and 18 h from feeding. Consumption of 100 or 1,000 mg TRH increased mean serum concentrations of thyroxine (T4; P less than .001), 1,000 mg TRH increased growth hormone (GH; P less than .06) and 100 or 1,000 mg TRH increased prolactin (PRL; P less than .01), but insulin (INS; P greater than .10) was unaffected by TRH. Serum concentrations of T4 were elevated within 2 to 4 h after feeding TRH and remained elevated for 12 to 18 h. Concentrations of GH and PRL began to increase immediately after feeding 100 or 1,000 mg TRH and remained elevated for 6 and 8 h, respectively. In Exp. 2, sows were fed 0 or 200 mg TRH from d 111 of gestation to weaning at 27.1 +/- .3 d of lactation. Consumption of TRH elevated concentrations of T4 at all stages of lactation and increased respiration rate on d 10 and d 20, heart rate on d 20, and milk production on d 20 of lactation. Consumption of TRH did not influence number of pigs born, number born alive, survival rate during lactation, sow body weight, heartgirth, backfat depth, feed disappearance, or milk production on d 10 of lactation. Piglets nursing sows fed TRH were similar in weight to piglets nursing sows not fed TRH on d 0 and 5 of lactation, but they were heavier on d 10 (P less than .07), 15 (P less than .001), 20 (P less than .001) and 27 (P less than .0001). Sows fed TRH took longer (P less than .001) to return to estrus after weaning than control sows. Results indicated that feeding TRH elevated T4, GH and PRL and that feeding TRH for the duration of lactation increased milk production on d 20 of lactation and increased weaning weights, but it delayed estrus after weaning.     

The influence of gestational dietary calcium on serum 1, 25-dihydroxycholecalciferol in sows and their pigs

Fifteen multiparous sows (three groups of five) were studied during one gestation-lactation cycle to measure the influence of dietary Ca (.5, .8[control], and 1.1%) on 1,25-dihydroxycholecalciferol (1, 25-(OH)2D3) in serum and colostrum of the sows and serum of their pigs. Concentrations of 1,25-(OH)2D3 and Ca, Mg, P, Cu, and Zn were determined on d 15 and 45 of gestation, at parturition, and at 3 wk postpartum in sow serum and at birth and d 10 and 21 in pig serum. Colostrum was assayed for 1,25-(OH)2D3. Serum 1,25-(OH)2D3 in sows was affected inversely (P less than .05) by dietary Ca within d 15 of gestation and was correlated (r = -.88) with serum Ca during gestation and lactation. Serum Ca was correlated (r = .52) with dietary Ca at d 15 and 45 of gestation and at farrowing. Sow serum Mg was inversely related (r = -.49) to serum Ca during gestation and early lactation. Serum 1,25-(OH)2D3 of the pigs at birth ranged from 38.7 to 44.2 pg/ml was decreased (P less than .05) by 1.1% maternal Ca intake. Sow colostrum 1,25-(OH)2D3 was related (P less than .05) inversely (r = -.40) to sow dietary Ca and directly (r = .90) to sow serum 1,25-(OH)2D3. Serum 1,25-(OH)2D3 of 10- and 21-d-old pigs was inversely related (P less than .05) to their dams' dietary Ca. These results indicate that 1,25-(OH)2D3 production in sows is quickly affected by modest changes in dietary Ca.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of additional feed during late gestation on reproductive performance of sows: a cooperative study

A cooperative research study involving 1,080 litters was conducted at eight stations to determine the effects of additional feed during the last 23 d of gestation on reproductive performance of sows and on preweaning performance of their pigs. Primiparous and multiparous sows were fed fortified corn- or sorghum-soybean meal diets (14% crude protein). Control sows received 1.82 kg/d from March through November and 2.27 kg/d from December through February. Treated sows were fed an additional 1.36 kg of feed/d from d 90 of gestation to farrowing. Sows were allowed to consume the same diet ad libitum during a 21-d lactation. Additional feed in late gestation resulted in greater (P less than .001) sow weight gain from d 90 to d 110 of gestation (16.8 vs 9.0 kg) and greater (P less than .001) parturition-lactation weight loss (21.3 vs 16.4 kg). Total weight gain from breeding to 21 d of lactation favored sows that received extra feed (27.5 vs 22.7 kg; P less than .001). Sows receiving extra feed had more live pigs at farrowing (10.05 vs 9.71, P = .06) and at 21 d postpartum (8.35 vs 8.06, P = .09), and the pigs were heavier at birth (1.48 vs 1.44 kg, P = .003) and at 21 d (5.37 vs 5.20 kg, P = .006). Lactation feed intake and number of days from weaning to estrus were not affected by treatment. The results indicate that additional feed in late gestation improves reproductive performance in sows. In this study, the cost of an additional 31 kg of feed/sow was more than offset by the value of the additional sow weight gain (approximately 5 kg), the additional .3 of a pig/litter at weaning and the additional 2.6 kg of total litter weaning weight.     

The effects of dietary fat or fiber addition on yield and composition of milk from sows housed in a warm or hot environment

Sixty sows were individually penned in a thermoneutral (20 degrees C) or hyperthermal (32 degrees C) environment and fed a basal (corn-soybean meal), high-fiber (48.5% wheat bran) or high-fat (10.6% choice white grease) diet from d 100 of gestation through a 22-d lactation. The diets were determined to contain 3.28, 2.76 and 3.75 Mcal ME/kg, respectively. All pigs received 8.0 Mcal of ME and 17.5 g of lysine daily prior to parturition and were allowed to consume their respective diets ad libitum after parturition. Litter size was standardized at 9 to 10 pigs by d 2 postpartum. Milk yields were determined for five, 4-d periods from about d 2 through 22 of lactation via a D2O dilution technique. Daily milk yield and litter weight gain began to plateau, and the efficiency of utilizing milk DM and milk energy for gain was depressed (P less than .01), in the latter stages of the lactation. Heat exposure (32 degrees C) reduced (P less than .05) voluntary ME intake and milk energy yield of the sow and increased (P less than .05) the sow's weight loss during lactation. In the hot environment, increasing dietary energy concentration resulted in a linear (P less than .08) increase in milk fat content and milk energy yield over the duration of the 22-d lactation. In the latter stages of lactation, pigs consuming high-fat milk required more (P less than .09) milk and milk energy per unit of weight gain. In the warm environment, milk energy yield was increased by dietary fat or fiber additions in early lactation, but not in late lactation. These results indicate that the effects of thermal heat stress on sow milk energy yield and litter weight gain are aggravated by dietary fiber addition and minimized by dietary fat addition.     

Effect of Lactation Diet Fat Level on Sow and Litter Performance

The primary objective of this study was to determine the effects of supplemental dietary fat during lactation on sow BW, sow backfat thickness, sow feed consumption, litter size, and pig growth rate. Dietary treatments included 0, 3, 6, and 9% supplemental low acid yellow fat in a traditional corn-soybean meal basal lactation diet. A total of 160 Landrace and crossbred sows (approximately 40 per treatment) were included in the study. Sows fed 3 and 6% supplemental fat had greater (P<0.10) average backfat thickness at weaning. Sow weight change and feed consumption were inconsistent among dietary fat levels. Dietary fat level during lactation did not affect number of pigs born alive or number of stillborns. However, the 9% fat level was associated with more mummified pigs at birth. Number of pigs weaned was greater for the 0% supplemental fat than for the 9% fat level. The largest average pig weights at 21 (5.8±0.29 kg) and 28 (7.48±0.38) d of age were those from sows fed the 3% added fat diet. Sows with ≤25.4 mm backfat at farrowing had more pigs born alive (P<0.05), had less backfat at 21 and 28 d of lactation (P<0.05), and consumed more feed during wk 2 and 3 of lactation. Of all sows fed the control diet, sows with >25.4 mm backfat at farrowing consistently had heavier pigs throughout the lactation phase (P<0.05). Backfat loss during lactation was lower (P<0.05) for sows with ≤25.4 mm at farrowing within all dietary treatments. Consistent significant differences were not observed in sow weight loss or feed consumption between low and high backfat sows for each dietary treatment. Sow backfat loss during lactation is dependent on body condition at farrowing, in that, fatter sows at farrowing have greater backfat loss during lactation. Sows with ≤25.4 mm of backfat at farrowing responded to added dietary fat treatments and produced heavier pigs throughout the lactation period.