Effects of biotechnical management procedures on blood parameters in gilts. 3. Lipids

Suisynchron treatment was applied to platform-kept gilts over 20 days. The dosage was 100 mg per animal and die. This was followed by 1,000 I.U. PMS and 250 I.U. HCG. Artificial insemination was applied five days after the first hormone administration and followed by one Gravigonan injection after another twelve to 15 days. Blood samples were drawn from those animals as well as from 20 gilts synchronised in the above way and another 20 untreated gilts from a production unit during the various phases of treatment and cycle. Those samples were used for assessment of cholesterol, lipoid-P, free fatty acids, triglyceride, and beta-lipoproteids. The levels of free and total cholesterol went up along with Suisynchron feeding, whereas lipoid-P and beta-lipoproteids declined. Free fatty acid levels went down with significance (P less than 0.01), and triglycerides increased (P less than 0.05). Cholesterol levels were not altered by PMS/HCG administration. The levels of lipoid-P, free fatty acids, and beta-lipoproteids rose to their magnitudes prior to Suisynchron treatment. Tirglycerides rose by 50 per cent. At the time of full oestrus triglyceride levels doubled (P less than 0.01). Unimportant rises were recorded also for cholesterol, beta-lipoproteids, free fatty acids, and lipoid-P. In animals with spontaneous oestrus all lipid parameters were ligher than in sows with full oestrus after synchronisation.     

Effect of biotechnical management procedures on blood parameters in gilts. 1. Acid and alkaline phosphatase

Three independent experiments were conducted with cyclic gilts kept under different conditions (2 x 12 on platforms and 100 from production unit), i.e. hormonally unaffected or under the usual conditions of synchronised oestrus (100 mg Suisynchron per animal and die over 20 days followed by 1,000 I.U. PMS and again followed, three days later, by 250 I.U. HCG). Blood samples were repeatedly drawn from the jugular vein and brachiocephalic vein during phases of treatment and oestrus. Acid and alkaline phosphatases were determined immediately in the plasms, and the results were calculated by variance analysis. Synchronisation, using Suisynchron, proved conducive to lowering with significance (P less than 0.01) the levels of acid and alkaline phosphatases. All changes in phosphatase values were not in full conformity within the experiments during the other phases of treatment. Phosphatase levels were not affected by discontinuation of Suisynchron nor by administration of Gn hormone. The levels of acid and alkaline phosphatases in biotechnically treated animals appeared to be lower than those in animals with spontaneous oestrus at the time of full oestrus. While the findings were of period-specific significance (P less than 0.01), the results obtained from the individual animal failed to provide specific information, since gaps were too wide between animals and between animals, on the one hand, and periods, on the other (P less than 0.01).     

The dose precision of PMSG in young and old sows in the process of biotechnical ovulation synchronization. 1. Comparison of diagnostic laparotomy

Treatment was applied, on two farms, to 272 gilts and 169 adult sows, 24 hours after discontinuation of Suisynchron application to the gilts or weaning of piglets of adult sows. Included were 600, 800 or 1,000 IU of PMSG for the gilts and 750, 1,000 oder 1,250 IU of the same batch (Pregmagon-Dessau) for the adult sows for ovarian stimulation. This was followed by application of 500 IU of HCG to the gilts or 300 micrograms Gn-RH vet. "Berlin-Chemie" + 300 IU HCG to the adult sows for synchronised ovulation. Laparotomy was performed on the gilts on the fifth day from PMSG application and on the adult sows on the fourth day. Average ovariotropic stimulation was "mild" in response to lower doses (14.8 follicles in gilts and 20.4 follicles in adult sows) but was "pronounced" in response to medium doses (19.4 or 22.7 follicles, respectively). The pharmacological concept of "mild" exogenic ovarian stimulation by low dosage at the threshold of effectiveness should deserve more attention, last but not least, for breeding aspects. The two groups of animals on both farms differed considerably from one another with regard to reactivity, which cannot be etiologically interpreted for the time being.     

Histological findings on the uterus of gilts following synchronized ovulation

Histological studies were undertaken with the view to testing uterus structure and function of gilts following synchronised ovulation by means of different PMSG doses. All proband groups received 500 I.U. HCG. All histomorphological, histochemical, and histometric checks revealed 500 I.U. PMSG to be too low a dosage, whereas the optimum amount was found to be between 750 and 1,000 I.U. PMSG. The uterine glands of all treated animals in all three groups were less favourably developed than those of the untreated controls. The best morphologico-histochemical pattern was observed following administration of 750 I.U. PMSG.     

Experiments in biological engineering to induce puberty in young female swine. 4: Ovulation period after puberty in animals aged about 200 days, using different combinations of gonadotropic hormones

44 prepuberal gilts were treated with gonadotropic combinations and investigated for ovarian dynamics. 400 PMS + 200 HCG (Suigonan-Vemie) induced ovulations at the 4th day p.i., 100 FSH + 100 HCG resp. 200 FSH + 200 HCG at the 6th day p.i. At the 8,-11th day p.i. the PMS/HCG-treated animals showed corp. lut, in 100, the FSH/HCG-treated in 50 resp. 87% of the cases. A second injection of 250 HCG 3 days after 200 FSH + 200 HCG increased the number of animals which had ovulated. Zystic ovaries (larger than or equal to 11 mm) developed in all groups. Declaration of gonadotropins in "international units".     

Effects of Turisynchron and Suisynchron on the thyroid gland in rats during simultaneous administration of TSH]

Thyrotrophin was injected i/p at 2 I.U. daily simultaneously with oral administration of Turisynchron at 100 mg/kg or Suisynchron at 125 mg/kg daily for five days to Wistar rats. The uptake of radio-iodine by the thyroid was reduced, and there were slight changes in thyroid structure. Suisynchron produced a milder inhibition of thyroid regulatory mechanisms than Turisynchron.     

The appearance of ovarian cysts in young sows after treatment with gonadotropin preparations for estrus induction

In 72 (46%) of 155 gilts discarded for genetic reasons after performance testing and housed under fattening conditions no heat could have been detected during the first 30 days. The gilts were assigned alternatingly to a control group and four different treatments of delayed puberty. The induction of puberty was carried out by injections of 1000 iu PMSG, 400 iu HCG and 2 mg oestradiol benzoate, 400 iu PMSG and 200 iu HCG and 800 iu PMSG and 400 iu HCG. If there was no estrus gilts were slaughtered 12 days later for examination of the ovaries. Those coming into estrus were slaughtered 8 days after disappearance of estrus. Estrus could be induced in 69 to 94% of the gilts, whereas 40% of the untreated showed estrus signs. After treatment with PMSG and HCG in 40 and 87% of the gilts cysts were found whereas none of the untreated and 26 and 29% of those treated with PMSG und HCG + oestradiol benzoate revealed ovarian cysts. In addition, those gilts that had come into estrus during the first 30 days were given injections of either 1000 iu PMSG or 800 iu PMSG and 400 iu HCG. The injections were made either on the 5th, 10th or 15th day of cycle. In both latter groups significantly more gilts showed standing heat than after treatment at cycle day 5. The results of inspection of the ovaries at slaughter and steroid hormones could not be assigned to a defined stage of the physiological ovarian cycle.(ABSTRACT TRUNCATED AT 250 WORDS)     

Attempts at biotechnical induction of puberty in young female pigs. 2. Effects of various time intervals between one puberty induction with PMS and HCG to the following estrus synchronization on estrus and ovulation in animals about 190 days old

A biological engineering approach to induce puberty in 125 young female fattening pigs aged 190 days was undertaken on the basis of a mixture of 500 IU PMS (Prolosanserum, Dessau) with 250 IU HCG (Gonabion, Dresden). The injections were made subcutaneously. Pronounced oestrus symptoms were recorded from the external genital organs of 80% of the probands up to ten days after injection, associated with toleration in 52.8% of them. Toleration usually started on the fourth to sixth days after injection. Cycles began to develop in 57.1% up to the next oestrus period. Animals with -/x weight increase per die of 400 g exhibited lower responses. Results in terms of heat and ovulation were lower along with shorter intervals, when oestric synchronisation was undertaken 53, 32, and 17 days after the induction of puberty (20 days Suisynchron, Bernburg; 750 IU PMS).     

Conclusions on the use of Suisychron in the USSR

Suisynchron was applied to 2,258 gilts, including 850 from breeding farms. Forty-four pigs were checked to elucidate the influence of sexual maturity on the success of oestrus synchronisation. Suisynchron-Pr?mix was fed to the animals over 20 days, the daily dose for each pig having been 5 g. Twenty-four hours were allowed to elapse from the last administration before 1,500 I.U. PMSG were injected. Synchronised oestrus occurred in 81.2 per cent of all pigs between four and six days from serum injection.Fertilisation in response to first insemination was recorded from 72.9 percent of the pigs, their fertility rate being 9.7 piglets from each farrowing sow. The results of oestrus synchronisation obtained from fattening pigs were somewhat inferior to those recorded from pigs of breeding units. Suisynchron and serum of pregnant mares can synchronise oestrus in 91 per cent of all mateable sows with no previous cycle. The fertility rates recorded from such pigs did not exceed 59 per cent or were between 28.9 and 31.9 per cent lower than those recordable from pigs with a cycle history prior to the use of Suisynchron.     

Prostaglandin-induced abortion in swine: endocrine changes and influence on subsequent reproductive activity

Gilts were treated during midgestation with prostaglandin (PG) F to study the efficacy of different treatment regimens on induction of abortion and to determine the adverse consequences of PGF-induced abortion in swine. In study 1, pregnant purebred Duroc gilts (60 to 90 days of gestation) were given (IM) 500 micrograms of cloprostenol (n = 12), 20 mg of dinoprost tromethamine (n = 11), or 10 mg of dinoprost tromethamine repeated 12 hours later by an additional 10 mg of dinoprost tromethamine (n = 11). The percentage of gilts that aborted and percentage of aborted gilts that returned to estrus for each treatment group were as follows: cloprostenol, 91.7% and 100%, respectively; 20 mg of dinoprost tromethamine, 36.4% and 25.0%, respectively; and 10 + 10 mg of dinoprost tromethamine, 100% and 90.9%, respectively. Treatment with cloprostenol and with 10 + 10 mg of dinoprost tromethamine caused more gilts to abort (P less than 0.01) than did treatment with 20 mg of dinoprost tromethamine. Gilts that did not abort were given a second treatment with 10 + 10 mg of dinoprost tromethamine. When the abortions by gilts initially treated with 500 micrograms of cloprostenol or 10 + 10 mg of dinoprost tromethamine were combined with those re-treated with 10 + 10 mg of dinoprost tromethamine, 32 of 33 (97.0%) gilts aborted, and 30 of the 32 (93.8%) aborted gilts returned to estrus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Response of gilts with delayed puberty to pregnant mare serum gonadotropin or estrogen

The effect of pregnant mare serum gonadotropin (PMSG) or estradiol cyclopentylpropionate (EC) on the induction of estrus, duration of estrus, and serum progesterone concentration after estrus was evaluated in 8 gilts with delayed puberty. Four gilts were given 500 IU of PMSG IM and 4 were given 2 mg of EC, IM. The inactive status of the ovaries at the time of treatment was verified by serum progesterone values of less than 0.5 ng/ml in serial samples collected before treatment. The 4 EC-treated gilts came into estrus at a mean of 3.5 days after treatment, but 1 of the gilts did not form corpora lutea. Three PMSG-treated gilts came into estrus at a mean of 4.0 days after treatment. The remaining PMSG-treated gilt remained anestrus and did not form corpora lutea. The mean duration of estrus in EC-treated gilts was 5.25 days compared with 2.0 days for PMSG-treated gilts (P less than 0.05). Serum progesterone concentrations were higher in PMSG-treated gilts than in EC-treated gilts at 8, 11, and 17 days after treatment (P less than 0.05).     

Clinical study results of the embryonic development in gilts and brooding performance of gilts and sows after HCG treatment on the 11th day of pregnancy

Forty-four pregnant gilts were slaughtered on the 32nd and 33rd days of pregnancy, after 30 of them had received 100 or 400 IU of HCG on the eleventh day of pregnancy. Both doses had resulted in higher number of living embryos. Embryo survival rates of treated sows were up to 14.9 percent higher than those of untreated animals. Higher numbers of embryos had no adverse effect on their mass development. Fertility was measured of 77 HCG-treated and untreated gilts as well as of 54 adult sows. The number of non-pregnant sows which returned to oestrus was higher in the group of gilts and adult sows which had received treatment. The number of pregnant animals in the treated adult sow group was seven percent higher than that in the control group. Increased litter sizes were additionally recordable from those gilts and adult sows that had received HCG injections. Yet, those higher litter sizes were associated with lower weight of live-born piglets. In further studies more attention should be given to possible stimulation of LH secretion in early gravidity.     

The course of ovulation in gilts after the partial replacement of HCG by GnRH for ovulation stimulation

The ovulation status and the amount of ovulated follicles were determined in 3 experiments from 197 gilts which had been given differentiated treatment and which were subsequently slaughtered. Ovulation stimulation produced high synchronisation effects, as compared to untreated animals. Partial substitution proved possible of Gn-RH vet. "Berlin-Chemie" for 500 I.U. of HCG which were generally used to stimulate ovulation, since the amount of ovulated follicles 169 hours from the last application of Suisynchron premix was in all 3 cases above the specified value of 85.0 per cent even after injection of 300 I.U. HCG/300 micrograms Gn-RH.     

Die Reaktionsfähigkeit des Ovars von praepuberalen und geschlechtsreifen Jungsauen auf ein PMS/HCG – Präparat Mit Unterstützung durch die Deutsche Forschungsgemeinschaft

Inhalt Jungsauen im Alter von 150 Tagen reagierten zu 90 % mit Brunst und Ovulationen (Ø 10,4 Gelbkörper) auf die einmalige Injektion einer Gonadotropinkombination aus 400 IE/PMS und 200 IE/HCG. Nur 33 % wiederholten die Rausche nach 3–4 Wochen. Hormonbehandelte 180 Tage alte Jungsauen kamen dagegen zu 90 – 100 % in einen Sexualzyklus. Das Uteruswachstum war altersabhängig: nach induzierten Ovulationen mit 150 Tagen wogen die Uteri durchschnittlich 126 g, nach Behandlungen bei 180 Tagen durchschnittlich 425 g. Auch geschlechtsreife, diöstrische Jungsauen reagierten zu 80 – 100 % auf das gleiche Präparat. Injektionen in der frühen und mittleren Lutealphase wurden nach 6 – 12 Tagen mit azyklischen Rauschen und Ovulationen beantwortet. Durchschnittlich 10 Eier wurden ovuliert, etwa die Hälfte der Tiere besaβ Zysten oder Blutfollikel. Behandlungen am 15./17. Zyklustag führten zu ausgeprägten Rauschen am 21./22. Tag und Ovulationen mit erhöhter Ovulations-rate (15,8 Eier). Pathologische Follikelbildungen wurden dann nicht gefunden. Contents (The reactivity of the ovary of prepubertal and sexually mature gilts to PMS/chorionic gonadotrophin hormone preparations). Following a single injection of a hormonal compound consisting of 400 i.u. PMS and 200 i.u. HCG to a 150 days old prepuberal gilts, 90% of them showed oestrus and ovulated (10.6 C.L./animal). Only 35% of these animals repeated oestrus 3 weeks later. When the same hormonal compound was given to 180 days old prepuberal gilts, 90–100% of the gilts repeated their oestrus. The degree of uterine development following this treatment was dependant on age of animals; in the 150 days old group, the av. uterine weight was 126 gm, and in the 180 days group, it increased up to 425 gm. In puberal gilts treatment with the same hormonal compound between day 4–14 of the oestrus cycle resulted in non-cyclic oestrus and ovulations 6–12 days after treatment. The number of ovulation points was 10 on the av., but 50% of the animals showed cysts or blood follicles on their ovaries. Treatment at day 15–17 of the cycle resulted in marked heat symptoms on day 21–22. The number of ovulation points was higher (15,8 on the av.) and pathological follicles were absent in this group.     

Effects of P.G. 600 on the onset of estrus and ovulation rate in gilts treated with Regu-mate.

Three experiments assessed the onset of estrus and ovulation rate in gilts treated with gonadotropins after the withdrawal of an orally active progestin. In Exp. 1, all cycling gilts received the progestin (Regu-mate; Intervet America Inc., Millsboro, DE) at a rate of 15 mg/d for 18 d. Twenty-four hours after the last feeding of Regu-mate, 32 gilts received an i.m. injection of 400 I.U. PMSG and 200 I.U. hCG (P.G. 600, Intervet America, Inc.), and 32 gilts received an i.m. injection of deionized water. The percentage of gilts displaying estrus < or = 7 d (P = 0.64) and the injection-to-estrus interval (P = 0.37) were similar for P.G. 600-treated gilts (93.8% and 4.1 +/- 0.1 d) and controls (90.6% and 4.3 +/- 0.1 d). Ovulation rate was greater (P < 0.01) in P.G. 600-treated gilts (28.8 +/- 1.1) compared with controls (17.4 +/- 1.1). In Exp. 2, 58 cycling gilts received Regu-mate (15 mg/d) for 18 d. Twenty-four hours after Regu-mate withdrawal, gilts received i.m. P.G. 600 or water (n = 29/treatment). Gilts were bred via AI 12 and 24 h after first detection of estrus. The percentage of gilts displaying estrus < or = 7 d (P = 0.45) and the injection-to-estrus interval (P = 0.27) were similar for P.G. 600-treated gilts (82.7% and 4.0 +/- 0.1 d) and controls (89.7% and 4.2 +/- 0.1 d). Ovulation rate was greater (P < 0.01) in P.G. 600-treated gilts (26.2 +/- 1.8) compared with controls (18.1 +/- 1.7). Pregnancy rate (P = 0.71) and the number of live embryos at d 30 postmating (P = 0.40) were similar for P.G. 600-treated gilts (91.7% and 15.6 +/- 1.2) and controls (88.5% and 14.1 +/- 1.2). In Exp. 3, prepubertal gilts (142.6 +/- 0.7 d of age) received Regumate (15 mg/d) (n = 20) or a control diet not including Regu-mate (n = 20) for 18 d. Twenty-four hours after Regu-mate withdrawal, all gilts received i.m. P.G. 600. The percentage of gilts displaying estrus < or = 7 d (P = 0.49) and the P.G. 600-to-estrus interval (P = 0.69) were similar for Regu-mate-fed gilts (95% and 4.3 +/- 0.2 d) and controls (88.9% and 4.2 +/- 0.2 d). Ovulation rate was similar (P = 0.38) for Regu-mate fed gilts (16.6 +/-1.6) and controls (14.4 +/- 1.8). In cycling gilts, administration of P.G. 600 after withdrawal of Regu-mate increased ovulation rate, but not litter size at d 30 postmating. There was no beneficial effect of Regu-mate pretreatment on the response to P.G. 600 in prepubertal gilts.     

Effects of adrenalectomy and glucocorticoids on puberty in gilts reared in confinement

The effect of adrenal function and flumethasone (FM, a synthetic glucocorticoid) on induction of puberty in crossbred gilts raised in confinement was examined in two experiments. In Exp. 1, gilts were adrenalectomized (Adx) or subjected to sham adrenalectomy (Sham) between 140 and 160 d of age. Twenty days later indwelling jugular catheters were implanted in Adx, Sham and another group of intact gilts designated as Controls, and the gilts were moved from confinement to outdoor pens and checked daily for estrus with a mature boar. Fewer (P less than .05) Adx (1/11) than Sham (9/14) gilts showed estrus and ovulated by 205 d of age. Response of Control gilts (6/14) was not different from the other groups. Although Adx gilts received 40 mg cortisone acetate and 10 mg deoxycorticosterone acetate daily throughout the experiment, mean plasma glucocorticoids were lower (P less than .05) in Adx (24 +/- 4.7 ng/ml) than in either Sham (47 +/- 8.1 ng/ml) or Control (44 +/- 6.1 ng/ml) gilts. Experiment 2 was conducted to determine whether FM given to Adx gilts immediately after surgery could have inhibited estrus and ovulation. Intact gilts received a total of 27.5 (FM1) or 17.5 (FM2) mg FM over 4 d between 150 and 160 d of age before relocation and boar exposure 20 d later. Control gilts received no injections. Nine of 13 FM-treated but none of the Control gilts showed estrus. It is concluded from these results that the adrenal glands may facilitate the onset of puberty in gilts through increases in glucocorticoid production, but that this is not required for puberty to occur.     

The effects of recombinant porcine somatotropin on reproductive function in gilts treated during the finishing phase.

The objective of this study was to determine the effects of recombinant porcine somatotropin (rpST) treatment during the finishing phase on subsequent reproductive function in crossbred gilts. Forty gilts weighing 50 kg and housed in a swine finishing facility were randomly assigned to control or rpST treatment. Four control and four rpST-treated gilts were allotted per pen. Twenty rpST-treated gilts received 6 mg of rpST.gilt-1.d-1 in 1 ml of buffered carrier and 20 control gilts received 1 ml of buffered carrier.gilt-1.d-1. Injections were administered daily at 1400 in the extensor muscle of the neck. All gilts received an 18% CP diet containing 1.2% lysine. Treatment was terminated when the average weight in each pen reached 110 kg. Gilts treated with rpST gained more weight (P less than .05) than control gilts (59.8 +/- 1.0 vs 53.5 +/- 1.0 kg). Age at puberty was not different (rpST, 182.2 +/- 3.3; control 181.4 +/- 3.1 d). Prior treatment with rpST did not significantly affect length of estrus (rpST, 1.9 +/- .1; control, 1.8 +/- .1 d) or estrous cycle length (rpST, 20.6 +/- .4; control, 20.4 +/- .4 d). Ovulation rates at second estrus were similar for rpST gilts (15.1 +/- .5) and control gilts (14.4 +/- .5). More embryos (P = .10) were recovered on d 9 to 12 of gestation from rpST-treated gilts than from control gilts (13.1 +/- .9 vs 10.7 +/- .9).(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in plasma follicle-stimulating hormone, luteinizing hormone, estrogen and progesterone during growth of ovulatory follicles in the pig

This experiment was conducted to determine the changes in secretion of LH, FSH, estrogen and progesterone during follicle maturation. Ovaries were recovered from 11 non-treated (control) gilts, three on day 13, four on day 16, and four on day 19 of the estrous cycle, and from four altrenogest-treated gilts on day 19. Altrenogest, a progesterone agonist, was fed at a dose of 20 mg once daily from days 13 to 18 to block spontaneous follicle maturation. Gilts were bled daily from day 12 until slaughter. For control gilts, the number of follicles/gilt 1-6 mm in diameter decreased (P less than .05) from 93.5 on day 13 to 21.5 on day 19, and the number of large (greater than 6 mm) follicles increased (P less than .05) from 5.3 to 13.2. Altrenogest treatment blocked loss of small follicles and growth of large follicles between days 13 and 19. Plasma progesterone decreased (P less than .001) between days 12 and 16 in both control and altrenogest-treated gilts. Plasma FSH decreased (P less than .05) between days 12 and 16 only in control gilts. Plasma LH was not significantly affected by day or altrenogest treatment. Plasma estrogen increased (P less than .05) between days 15 and 19 only in control gilts. These results indicate that 1) no increased LH secretion was detected in conjunction with emergence of ovulatory follicles, and 2) atresia of nonovulatory follicles was associated with decreased secretion of FSH. Both atresia and decreasing FSH secretion began before estrogen concentration increased in the systemic circulation.     

Quantitation of prolactin-dependent responses in porcine mammary explants

A system was developed to quantitate prolactin-dependent responses in porcine mammary tissue obtained from pregnant gilts. Metabolic responses to prolactin (Prl) and cortisol (C) in the presence of varying doses of insulin (I) were examined in mammary explants cultured on the surface of the medium or submerged in medium, under an atmosphere of humidified air. Explants suspended on grids at the surface of medium oxidized 45% more glucose (P less than .05) and incorporated 67% more glucose into lipids (P less than .05) than explants submerged in culture medium. In explants cultured on grids, both 100 and 1,000 ng I/ml increased glucose oxidation (by 50%) and glucose incorporation into lipids (by 150%) compared with 10 ng/ml (P less than .05), but responses to 100 and 1,000 ng I/ml were not different. Therefore, in subsequent studies, explants were cultured on grids with 100 ng I/ml. Rates of glucose metabolism for mammary explants cultured with I + C for 48 or 72 h were not different from those in fresh tissue. However, addition of Prl (200 or 1,000 ng/ml) increased oxidation rate 130% and fat synthesis 400% compared with I + C (P less than .05). Addition of triiodothyronine to I + C + Prl further increased rate of fat synthesis by 87%. Dose-dependent responses to Prl were demonstrated and were within the concentrations of Prl found in blood of gestating gilts. These studies demonstrate that the lactogenic complex of I, C and Prl induces metabolic activity in porcine mammary tissue from late pregnancy.     

Experimental studies on the stimulation of prenatal development in swine by PMSG treatment in early pregnancy. 1. Clinical results of embryonic development in young slaughtered sows and litter results in young and old sows after PMSG treatment on the 11th day of pregnancy

Thirty-eight gilts were slaughtered on the 25th and 39th days of pregnancy, after they had received 400 I.U. PMSG treatment on the eleventh day of pregnancy. Treated and untreated animals in a group of 140 gilts and 195 adult sows were compared with each other for post-farrowing fertility performance. Weight development of embryos obtained from the slaughtered sows depended on the number of embryos alive. The survival rate of embryos from treated sows was about 5% higher than that recorded from untreated animals. Clearly increased litter sizes which, however, were associated with lower piglet birth weights were recorded from farrowing gilts and adult sows, following PMSG treatment. The conclusion is drawn that PMSG treatment, via luteotrophic action of luteinising hormone, is capable of stabilising pregnancy-related corpora lutei, resulting in higher litter sizes. Further studies will be necessary, and emphasis will have to be laid on the problem of weight development of newborn piglets, following litter-size boosting treatment.