不同形式补铁补硒对仔猪生长性能、血液生化指标、免疫性能的影响

[目的] 比较母猪和仔猪不同形式的补铁补硒对仔猪生产性能、血液生化指标、免疫性能的影响。[方法] 将32头母猪随机分为8组,每组4头,1~4组基础日粮中添加硫酸亚铁和亚硒酸钠,5~8组基础日粮中添加甘氨酸螯合铁和硒代蛋氨酸。2组和6组母猪所产仔猪于3日龄肌注铁硒合剂;3组和7组仔猪基础日粮中添加硫酸亚铁和亚硒酸钠;4组和8组仔猪基础日粮中添加甘氨酸螯合铁和硒代蛋氨酸;1组和5组仔猪饲喂基础日粮,不接受任何形式的补铁补硒。母猪预产期前30 d开始饲喂试验日粮,仔猪7日龄时开始饲喂试验日粮,试验至仔猪21日龄断奶结束。测定并比较不同组别仔猪生长性能指标、血液生化指标以及免疫性能指标,以及不同组别母猪初乳和常乳中的铁硒含量。[结果] 在仔猪补铁补硒形式相同的条件下,母猪基础日粮中添加甘氨酸螯合铁和硒代蛋氨酸（5~8组）与基础日粮中补充硫酸亚铁和亚硒酸钠（1~4组）相比,能够显著（P<0.05）或极显著（P<0.01）提高仔猪的初生重、断奶重、断奶存活率、断奶合格率,2日龄和21日龄血浆铁含量、血浆硒含量、血红蛋白含量、血浆转铁蛋白含量、IgA含量、IgG含量、IgM含量,以及母猪初乳和常乳中的铁硒含量;在2种形式的母猪补铁补硒条件下,与不补铁补硒相比,仔猪不同补铁补硒形式（2~4组和6~8组）对其断奶重、断奶存活率、断奶合格率,以及21日龄血浆铁含量、血浆硒含量、血红蛋白含量、血浆转铁蛋白含量、谷胱甘肽过氧化物酶活性、IgA含量、IgG含量、IgM含量均有极显著（P<0.01）的提高作用,并且仔猪基础日粮中添加甘氨酸螯合铁和硒代蛋氨酸的效果优于肌注铁硒合剂和基础日粮中补充硫酸亚铁和亚硒酸钠。[结论] 母猪和仔猪基础日粮中添加甘氨酸螯合铁和硒代蛋氨酸,能有效提升仔猪的生长性能、血液生化指标和免疫性能。     

Plasma ferritin of sows during pregnancy and lactation

We studied a set of indicators of iron metabolism in sows and new-born piglets: hemoglobin, plasma iron, total iron binding capacity and plasma ferritin. Iron status of seventy-two sows was studied throughout pregnancy and lactation. The results point to mobilization of iron from its storage sites up to the second month of gestation, but no appreciable decrease during the second half of pregnancy. No appreciable mobilization of the iron stores of sows was observed during the lactation period. Nine sows and their 78 piglets were used to compare the status of iron in the sows and the end of gestation with the iron status of the piglets at birth; there was a positive correlation between the mean values of plasma ferritin concentration in the piglets and the levels of plasma ferritin in their mothers.     

The content of Hb in blood and the protein, Fe, Fe-binding capacity, Cu and Zn in blood plasma of low parity sows before and after oral iron administration

In investigations of 51 pregnant sows, blood Hb levels above 7.45 mmol/l (mean value of 8.94 +/- 0.88) were recorded from 43 animals (Group A), while levels below that margin were recorded from eight (Group B) (mean value of 6.73 +/- 0.31). Iron levels in blood plasma of Group A were 36.9 +/- 8.07 and were thus higher (p less than 0.01) than those in Group B (28.9 +/- 5.19 mumol/l). No difference was found to exist between the two groups with regard to iron fixation capacity as well as copper and zinc in blood plasma. Oral uptake of 50, 500 or 2,000 mg of iron in the form of FeSO4.7H2O with cereal shred as morning ration by 17 or 15 sows failed to cause any increase in blood plasma iron levels, within 360 minutes from uptake. Literature data as well as the results of these analyses have supported the recommendation that Hb variations between 4.96 and 9.93 mmol/l (8-16 g/dl) should be rated as physiological in the blood of pregnant sows. The GDR Standard TGL 35,423 on "Monitoring of Metabolism on Pig Breeding and Fattening Units" should be accordingly amended.     

Changes in free amino acid serum levels in swine during parturition and in piglets during birth

During the course of parturition seven high pregnant sows, crossbreds of the Large White and Landrace breeds, and their 69 piglets being born, were studied for the changes of the total and separate free amino acids in the blood plasma in relation to the time of duration of the parturition, to the sequence of piglets being born in the litter, and to the birth weight of the piglets. The concentration of the total free amino acids in blood plasma is 2.44 +/- 0.182 mmol.l-1 just before parturition; after the birth of the last piglet it decreases insignificantly to 2.17 +/- 0.190 mmol.l-1. The concentration of the total free amino acids in the blood plasma of newborn piglets is always significantly higher than in their mothers (p less than 0.001) and is 4.24 +/- 0.109 mmol.l-1. The rank of each piglet in the sequence of births in litter has no influence on the level of plasma concentration of the total free amino acids amino acidaemia was 4.03 +/- 0.268 mmol.l-1 in the piglets born first and insignificantly changed to 3.99 +/- 0.445 mmol.l-1 of blood plasma in the last piglets born in the litter. The time factor of parturition is also statistically insignificant. However, the differences in the free "amino acids" concentration in the blood plasma between the piglets with the lowest weight and the piglets with a weight of up to 1200 and 1500 g are statistically significant (p less than 0.02). Alanine (0.43 +/- 0.052 mmol.l-1) and glycine (0.43 +/- 0.063 mmol.l-1) constitute the largest proportions of all the 17 amino acids studied in the blood plasma in the high pregnant sows before parturition. The tyrosine concentration in piglets at birth is remarkably high (1.44 +/- 0.035 mmol.l-1); it represent 34 per cent of the total amino acidaemia. Tyrosine, histidine and lysine concentration in the blood plasma is statistically highly significantly higher (p less than 0.001) in newborn piglets than in their mothers. The phenomenon of 6-times higher tyrosinaemia in piglets, compared with the sows is discussed in connection with the weight at birth and with the data on the function and concentration of thyroid hormones in piglets during the first days of their lives.     

Changes in fetal and maternal blood at the end of pregnancy and during parturition in the pig

Fetal and maternal blood gas tensions, pH, packed cell volume and glucose, fructose and lactic acid concentrations were monitored during the last two days of gestation, during parturition and and the first hour after birth. Blood samples were taken by means of indwelling catheters (implanted seven to 14 days before parturition) from 12 fetuses in seven sows. All fetuses were liveborn at a mean gestational age of 113.1 days. The significant finding was that all variables in fetal blood were stable during labour and, although mild hypercapnia was present during the last three hours, no significant changes in mean values were seen until those of samples taken within 15 minutes of birth. In some fetuses, no changes were seen until after birth, while in others pH and pO2 values declined during the last hour of fetal life. Immediately after birth a rapid increase in pO2 and decrease in pCO2 followed the onset of respiration. Blood pH fell during the first 30 minutes after birth and this fall was accompanied by increasing blood lactic acid concentrations. Blood glucose concentrations rose rapidly in the first 15 minutes after birth and were maintained during the first hour despite separation of the piglets from the sow. There was a transient, but significant, increase in packed cell volume during the period from 15 minutes before to 15 minutes after birth. Maternal values for all variables measured remained virtually unchanged during delivery.     

Concentrations of cortisol, glucose and free fatty acids in the blood plasma of swine in relation to age and in sows close to farrowing

The glucose concentration in sows tends to undergo slight rise within 24 hours from farrowing, while the concentration of free fatty acids declines from the onset of lactation. Cortisol went up on the day of farrowing and dropped afterwards, but neither movement was secured. The plasma values of newborn piglets were compared to those of their dams Cortisol was higher (15.0 +/- 6.4 and 9.7 +/- 3.7 microgram/100 ml), but glucose concentrations were lower (50 +/- 9 and 78 +/- 9 mg/100 ml), while the average levels of free fatty acids were in good agreement. In the nursing period, cortisol dropped to one fifth of the original value within 24 hours from birth and stayed at that level. Glucose increased to a maximum within twelve hours and declined continuously along with progressing nursing period. The level of free fatty acids, too, rose significantly up to the fifth day after birth. Cortisol, glucose, and free fatty acids in store pigs, aged 28 days, were lower than in nursed piglets of the same age.     

Effects of dietary glucose level during late gestation on litter performance and glucose concentration in sows

The effects of feeding glucose during the 5 days before parturition on litter performance and on glucose concentration in sows were studied. At day 100 of gestation, 130 multiparous sows were assigned to the treatments. Late gestating sows were fed 0 g, 150 g, 250 g, 350 g and 450 g of glucose a day, respectively. During lactation, all sows were given free access to the same lactation diet (without glucose). One day before parturition, blood samples were collected from 30 sows (6 sows per treatment) at 10 before and 20, 40, 60 and 80 min after the meal. The supply of additional dietary glucose increased piglet birth weight ( P  < 0.05). Feed intake in week 1 and week 1–4 of lactation was greatest in sows fed the 0% glucose diet, least by sows fed the 18% glucose diet, and intermediate by sows fed the 6, 10, 14% glucose diets ( P  < 0.05). Basal glucose concentration and time of maximum glucose concentration after glucose intake were not affected by dietary treatment in the last 5 days of gestation. The sows fed the 14 and 18% glucose diets had greater maximum increase in glucose concentration than sows fed diet without glucose ( P  < 0.05). In conclusion, feeding glucose to sows during 5 days before parturition increased birth weight of live-born piglet and decreased sows feed intake during lactation, but did not affect the performance of sows and piglets.     

Effect of the sow vaccination regimen on the decay rate of maternally derived foot-and-mouth disease antibodies in piglets

Three pairs of sows were vaccinated against foot-and-mouth disease (FMD) at various intervals before farrowing and samples of blood were collected from their piglets periodically for 70 days after birth. When the sows were vaccinated 12 to 13 days before farrowing the predominating FMD neutralising antibody at time of parturition was IgM and the observed half lives of the maternally derived antibodies in the piglets were short (four to eight days). However, when sows were last vaccinated 30 to 32 days before farrowing, the maternally derived FMD neutralising antibodies in the piglets were predominantly IgG and the observed half lives were seven to 21 days. These observed half lives for IgG were shown to be closely related to the period over which the maternally derived antibodies could be demonstrated and to the rate of increase of the piglet's blood volume over the same period. If corrections were made for increase in blood volume the decay rate of IgM antibodies in piglets was seven to 18 days while the decay rate for IgG was greater than 408 days. This result suggested that there was little or no IgG catabolism or excretion during the first 70 days of the piglet's life.     

Attempts to influence birth in swine with dexamethasone. 2. Effect of DXMS on adrenal mass and cell nuclear volume of the fascicular zone in piglets

The adrenal weights of spontaneously born piglets, immediately after parturition, were significantly higher than those of piglets from sows in whom parturition had been induced by DXMS. The differences between mean values went down with DXMS treatment started later in advanced pregnancy. Mean absolute and relative adrenal weights of the DXMS groups came closer to those of the untreated controls on the tenth day of piglet age. Cell nucleus volumes of the zona fasciculata were normal in all groups and did not reveal any influence of DXMS treatment in any of the newborn piglets. The mean values were 89.9 micron3 in the control group and 87.6 micron3 in experimental group V (75 mg DXMS per animal and die on 109th through 111th days of pregnancy).     

Studies on improving the fertility of aged sows. 3. Results of histological studies on puerperal involution and regeneration processes in the endometrium of lactating sows and sows after extremely early weaning]

Involution and regeneration following parturition was studied in 48 sows allowed to suckle their piglets normally, or from which the piglets were taken away at 5-8 days of age. Samples of uterus were obtained by biopsy 4, 8, 11, 14, 17, 20, 30, 32 and 40 days after parturition. In lactating sows, endometrial changes similar to those of oestrus in a normal cycle were present 32 days after parturition. This fact seems to justify the removal of piglets at 21-28 days of age. After very early weaning (5-8 days), incomplete oestrus-like changes in the endometrium were seen on the 17th day after parturition. The observed involutionary and regenerative changes in the puerperal uterus suggest that early weaning after 10-12 days of suckling is feasible, but it may be advisable to use drugs that would accelerate uterine involution.     

Variation in Vitamin E,Glutathione Peroxidase and Retinol Concentrations in Blood Plasma of Primiparous Sows and their Piglets,and in Vitamin E,Selenium and Retinol Contents in Sows' Milk

The concentrations of vitamin E, glutathione peroxidase (GSH-Px) and retinol were analysed in blood plasma of six primiparous sows during gestation and lactation and in their suckling piglets, and the concentrations of vitamin E, selenium and retinol were analysed in colostrum and in sows' milk. During late gestation the concentrations of vitamin E and retinol in blood plasma increased slowly while no changes were found for GSH-Px. This was followed by a large decline on the day of farrowing, when the lowest mean values of 1.07 mg, 0.15 mg and 2879 U per litre (l) of blood plasma, respectively, were recorded. During lactation the concentrations of vitamin E, GSH-Px and retinol in blood plasma of the sows increased to levels observed during late gestation. The highest mean concentrations of vitamin E (17.9 mg kg- 1 ), selenium (200 w g l- 1 ) and retinol (2.45 mg kg- 1 ) were found in colostrum, but with a large variation between sows. One week postpartum the concentrations of vitamin E, selenium and retinol in sow milk had decreased, on average by 86, 68 and 71%, respectively, after which only small changes occurred. Mean concentrations of vitamin E (1.77 mg l- 1 ), GSH-Px (682 U l- 1 ) and retinol (0.07 mg l- 1 ) were low in the blood plasma of the piglets at birth, but a large increase was observed on the next sampling occasion at the age of 3 days (vitamin E: 5.31 mg l- 1 ; GSH-Px: 996 U l- 1 ; retinol: 0.19 mg l- 1 ). The mean concentration of vitamin E in blood plasma of the piglets declined thereafter until the age of 6 weeks (1.04 mg l- 1 ), when there was a small increase, while the mean concentrations of GSH-Px and retinol continued to increase during the suckling period. A high correlation was found between the concentration of vitamin E in blood plasma and sidefat thickness of the sows (r = 0.94), and between the concentration of vitamin E in colostrum and vitamin E in blood plasma of the sows on the day of farrowing (r =0.77). High correlations were also found between the concentration of vitamin E in the blood plasma of the piglets at 3 days and 5 weeks of age and the concentration of vitamin E in colostrum (r = 0.78) and (r =0.89), respectively. The results indicate that vitamin E storage in the adipose tissues of the sow has a great influence on the supply of vitamin E via colostrum and milk to the piglet.     

Control of parturition in swine. 2. Study results of parturition synchronization in swine with the prostaglandin analog cloprostenol (I.C.I. 80.996: Estrumate)

Premature parturition was induced in 115 of 121 sows (95%) that had been given injections of 150 microgram or 200 microgram of "Estrumate", a prostaglandin analogues, on the 112th and 113th days of gestation. The average time that elapsed between injection and parturition of those 115 animals was 27.2 +/- 7.7 hours, with no difference being observed between gilts, on the one hand, and old sows, on the other. The time of gestation of the treated animals was shortened with significance from 114.6 +/- 1.6 days for the controls to 113.2 +/- 0.4 days. The average duration of parturition proper was 3.7 +/- 2.2 hours, the average litter being 11.2 +/- 3.3 piglets. The total number of piglets born was 1,320, with stillbirths accounting for 4.17%. The average weight at birth, 1,330 +/- 210 g, and the weight at weaning did not differ from weight figures recorded from the controls. The courses of parturition and puerperium were in agreement with normal biological standards. The sows treated were tested for their blood counts close to full term and for their endometrial histomorphology after weaning, with no side effects of "Estrumate" treatment being established. The behaviours of progesterone, 17-beta oestradiol, and cortisol in serum of "Estrumate"-treated sows were investigated, and congruence was established between spontaneous and prostaglandin-induced parturitions, which was in agreement with international literature. The conclusion is that 150 micrograms of 'Estrumate", administered to swine, after the 11th day of gestation has very good labour-inducing effects and ensures normal physiological parturition and piglet development.     

Timing and causes of piglet mortality in alternative and conventional farrowing systems

The causes and timing of piglet mortality were studied in different farrowing systems. In the first experiment 198 litters were recorded in three systems, two of which allowed the sows to move freely, and the third restricted them in conventional crates. More piglets were weaned from the conventional crates than from the open systems and they grew more quickly. More than half the liveborn mortality occurred during the first four days after parturition. In the open systems, 17 per cent and 14 per cent of the piglets born alive were crushed, compared with only 8 per cent in the crates. In the second experiment, 29 sows and litters were studied in detail in a communal pen system during the first seven days of lactation. Three-quarters of the liveborn mortality was due to crushing. The total number of piglets dying per litter, including stillbirths, was significantly associated with the total litter size and the sow's parity. The percentage liveborn mortality was significantly associated with the parity and body length of the sows and with the within-litter variation in the birth weight of the piglets. Individual birth weight was closely associated with percentage survival. Only 28 per cent of piglets weighing less than 1.1 kg at birth survived to seven days.     

母猪饲粮添加β-羟基-β-甲基丁酸对母猪繁殖性能及仔猪生长性能和免疫功能的影响

本试验旨在研究母猪饲粮添加β-羟基-β-甲基丁酸(HMB)对母猪繁殖性能及仔猪生长性能和免疫功能的影响。选取20头3～6胎次、妊娠74 d的"长×大"母猪,随机分成2组,每组10个重复,每个重复1头母猪,对照组饲喂基础饲粮,试验组在对照组基础饲粮中添加2 000 mg/kg HMB。试验从母猪妊娠第74天开始,至仔猪21日龄断奶结束。结果表明:与对照组相比,试验组仔猪初生个体重显著提高14.1%(P<0.05),仔猪7、21日龄窝重分别显著提高16.6%、11.7%(P<0.05),仔猪初生至7日龄、初生至21日龄窝增重分别显著提高28.3%和12.5%(P<0.05);与对照组相比,试验组母猪在妊娠第98天和分娩当天血清免疫球蛋白G(IgG)含量分别提高35.3%(P<0.01)、13.0%(P>0.05),免疫球蛋白M(IgM)含量分别提高34.7%(P<0.05)、12.6%(P>0.05);与对照组相比,试验组母猪初乳中IgG含量显著提高19.0%(P<0.05),分娩后第14天常乳中IgM含量显著提高21.4%(P<0.05);与对照组相比,试验组仔猪7日龄血浆IgG、IgM含量分别显著提高11.4%和40.1%(P<0.05)。上述结果提示,母猪妊娠后期及哺乳期饲粮中连续添加2 000 mg/kg HMB,可显著提高仔猪初生重和哺乳期增重,改善母猪及仔猪免疫功能。     

The postnatal iron status of trotter foals

The postnatal iron status of 20 trotter foals (7 female, 13 male) was studied by analyzing different parameters in blood drawn on the day of birth, and 14 +/- 2 and 28 +/- 2 days later. Hemoglobin hematocrit, plasma iron and transferrin saturation averaged 14.9 g/dl, 41.8%, 300 micrograms/dl and 59.4%, respectively, on the day of birth. These values were significantly reduced after 14 days, but had approached again the initial levels by day 28. There was a slight, statistically nonsignificant rise in the mean total iron-binding capacity over the four-week period. Iron status was not affecting by the sex of the foals. On the day of parturition, the mares had much lower levels of plasma iron and transferrin saturation than their foals. In the discussion, the importance of checking the iron status of each individual foal during the critical period of the first 14 days post partum is stressed.     

Plasma levels of cortisol in zero-weaned and lactating sows during the first two weeks post partum

The object of this investigation was to study the plasma levels of cortisol during the day of parturition and the first two weeks post partum in primiparous zero-weaned (weaned within 12 hr after birth) and lactating sows. Fourteen primiparous sows were used. They were grouped as follows: group A, (3 sows) zero-weaned, ovulating; group B, (4 sows) zero-weaned, anovulatory; group C, (4 sows) lactating with normal litter size; group D, (3 sows) lactating with small litter size. The peripheral plasma levels of cortisol were determined by radioimmunoassay throughout the experimental period,The peripheral plasma levels of cortisol were significantly higher in the anovulatory than in the normally ovulating sows. The lactating sows had almost the same levels of cortisol as the zero-weaned sows with anovulatory estrus. There was no difference in cortisol levels between sows nursing small or normal litters.It may be concluded that elevated plasma levels of cortisol might be one of several factors inhibiting the LH surge during the first estrus after zero-weaning. No relationship was found between cortisol levels and number of suckling piglets.     

Comparison effects of dietary iron dextran and bacterial‐iron supplementation on growth performance,fecal microbial flora,and blood profiles in sows and their litters

This study was conducted to compare effects of dietary administration of iron dextran and bacterial‐iron on growth performance, fecal microbial flora, and blood profiles in sows and their litters. A total of 20 multiparous sows (Landrace × Yorkshire) were randomly allotted into two treatments: (i) ID (basal diet, piglets were injected with iron dextran); (ii) BR (basal diet + bacterial‐iron; bacterial‐iron was given to sows, piglets were not injected with iron dextran). There were five replicates per treatment with two sows per replicate. No differences were observed on sow and piglet growth performance, fecal microbial flora as well as sow blood profiles between ID and BR treatments. In piglets, blood iron, red blood cell and hemoglobin concentrations in ID treatment were higher (P < 0.05) on days 12 and 24. Furthermore, concentration of white blood cells in BR treatment was lower (P < 0.05) on day 12. However, the percentage of lymphocytes on day 12 was increased (P < 0.05) in BR treatment. In conclusion, effect of iron dextran and bacterial‐iron has no difference on growth performance in lactating sows and piglets, but iron dextran injection has higher blood iron, white blood cell, red blood cell and hemoglobin concentrations in piglets.     

饲粮中添加不同水平L-精氨酸对妊娠母猪繁殖性能及血液生化指标的影响

本研究探讨饲粮中添加不同水平L-精氨酸(L-Arg)对母猪繁殖性能及血浆一氧化氮相关指标的影响。试验选择36头2胎次母猪(长白×大约克),随机分为4组,每组9头母猪。各组饲粮分别在基础饲粮中添加0 L-Arg+1.70%L-丙氨酸(L-Ala)(0 L-Arg组)、0.4%L-Arg+1.02%L-Ala(0.4%L-Arg组)、0.7%L-Arg+0.51%L-Ala(0.7%L-Arg组)和1.0%L-Arg+0 L-Ala(1.0%L-Arg组),各组添加L-Ala以满足等氮平衡需要。试验期从母猪配种当天到分娩。结果表明:1.0%L-Arg组比0 L-Arg组显著提高了窝产活仔数和初生窝重(P<0.05),随着饲粮中L-Arg水平的提高,窝产仔总数和初生个体重有上升趋势(P>0.05);母猪妊娠第30、60和90天,1.0%L-Arg组血浆中Arg、鸟氨酸含量均显著或极显著高于0.7%、0.4%、0 L-Arg组(P<0.05或P<0.01);母猪妊娠第90天,各组间的血浆脯氨酸含量均有极显著差异(P<0.01),但第30、60天差异均不显著(P>0.05);母猪妊娠第30、60、90天,1.0%L-Arg组血浆一氧化氮含量和第90天血浆总一氧化氮合酶(TNOS)、诱导型一氧化氮合酶(iNOS)活性均显著或极显著高于0.7%、0.4%、0 L-Arg组(P<0.05或P<0.01)。经回归分析,母猪的窝产仔总数、窝产活仔数、初生窝重、血浆中各氨基酸、一氧化氮含量及TNOS和iNOS的活性与饲粮L-Arg水平均有显著或极显著的线性关系(P<0.05或P<0.01)。结果提示,饲粮中L-Arg水平变化对母猪妊娠后期血液生化指标影响明显,饲粮中添加1.0%L-Arg对提高母猪繁殖性能效果最佳。     

Farrowing induction induces transient alterations in prolactin concentrations and colostrum composition in primiparous sows

Hormonal changes involved in the farrowing process partly control the initiation of lactation. Inducing farrowing by injection of PG may alter the normal prepartum hormonal cascade. The aim of the study was to investigate the consequences of farrowing induction on colostrum yield and composition, as well as newborn piglet growth. Gilts were treated with 2 mg of alfaprostol on d 113 of gestation (induced farrowing, IF, n = 9) or were injected with 1 mL of a saline solution (natural farrowing, NF, n = 11). Colostrum production was estimated during 24 h, starting at the onset of parturition, based on piglet BW gains. Colostrum samples were collected during the 36 h after the onset of parturition. Blood samples were collected from sows as of d 112 of pregnancy until d 2 postpartum (d 0 being the day of parturition). Piglet blood samples were obtained at birth, on d 1, and on d 21. Litter size and litter weight at birth did not differ between groups (P > 0.10). Farrowing induction did not influence (P > 0.10) colostrum yield (3.96 ± 0.20 kg) or piglet BW gain during d 1 postpartum (116 ± 8 g). At the onset of farrowing (T0), lactose content in colostrum was greater in IF sows than in NF sows (P < 0.05), whereas colostrum ash and protein contents were less (P < 0.05) in IF sows. Concentrations of IgG in colostrum were similar in both groups of sows, whereas concentrations of IgA at T0 were less in IF than in NF sows (P < 0.01). Overall, endocrine changes in blood from d -2 until d 2 (cortisol, prolactin, progesterone, and estradiol-17β) were not altered by farrowing induction (P > 0.10), but 1 h after the injection of alfaprostol, IF sows had greater circulating concentrations of prolactin (P < 0.01) and cortisol (P < 0.10) than NF sows. The greater concentration of lactose in colostrum from IF sows could be attributed to this transient increase in prolactin and cortisol. At birth, concentrations of white blood cells were less in piglets born from IF sows (P < 0.01). On d 1 and 21, piglets from IF sows had similar IgG concentrations in plasma to piglets from NF sows (P > 0.1). In conclusion, farrowing induction at 113 d of pregnancy induced transient hormonal changes in sows and alterations in colostrum composition, without significantly affecting colostrum yield. It also modified some hematological variables of piglets at birth.     

The influence of additional fat in the diet of sows before and after parturition on piglet viability and performance

Two hundred and six mature sows were used to evaluate the effect of adding a total of 3 kg of fat to sow diets for an average of eight days before and seven days after parturition on piglet viability and performance.The addition of fat to the diet of sows had no effect on the percentage of piglets born alive, individual piglet birth weight, weight of the piglet at three weeks of age or the weaning to service interval in the sows. However, there was a significant increase in piglet survival (3.4%) between treated and control sows. Birth weight had a marked effect on piglet survival but there was no indication of a greater effect of added fat in the sows' diet on the survival of smaller piglets. A number of piglets were cross-fostered but fostering had no effect on piglet mortality. A comparison of the mortality of piglets born from sows receiving added fat and reared on controls and vice versa indicated that the major benefits of additional fat in the sow diet were effected in utero rather than via an increase in the quality of the sows' milk.