关中驴分娩期血浆中孕酮和17β-雌二醇水平的变化

应用放射免疫分析法测定了13头怀驴关中驴分娩期的孕酮和17β-雌二醇水平。临近分娩时(分娩前4～14天),外周血浆17β-雌二醇水平逐渐升高,至分娩前1天出现低幅度波峰;而孕酮于分娩前3天上升之后,及至开口期一直未有特别改变。分娩前3天至胎衣排出期的孕酮和17β-雌二醇水平分别波动于7.10～8.17ng/ml 和30.3～57.6pg/ml 之间,无显著差异(PΚ0.05)。胎衣排出后,外周血浆两种激素的水平骤然下降,到胎儿排出后12小时,孕酮为2.12±0.31ng/ml,17β-雌二醇为13.8±1.6pg/ml,各相当于分娩前1天的26.7%和24.0%。本研究还确定了两种激素在脐静脉血浆与外周血浆中的含量呈平行变化:脐静脉血浆孕酮和17β-雌二醇同外周血浆对应激素的相关系数分别为0.93(P<0.01)和0.71(P<0.05)。此外,还发现尿水和脐静脉血浆17β-雌二醇水平均高于相应的羊水和脐动脉。     

湖羊围产期外周血浆中17β-雌二醇与孕酮水平的变化

选6只一岁第一胎怀孕母羊,在分娩前7天及分娩过程中采血,用放射免疫法测定外周血浆中17β-雌二醇、孕酮的含量. 湖羊在分娩前第7～3天,17β雌二醇波动在12.43～18.34pg/ml的低水平,随着分娩的临近,17β-雌二醇逐渐升高,并在开口期锐增达到88.84土43.37pg/ml,极显著地高于临产前水平(P<0.01)。到分娩当时17β-雌二醇达到最高水平100土71.58pg/ml,产后2小时降为32.11土19.00pg/ml,到产后12小时已接近基础值13.17土6.56pg/ml。湖羊在分娩前7天内,孕酮水平波动于5.69～3.09ng/ml之间。在开口期孕酮水平降到最低(2.72土0.98ng/ml),到分娩时及产后1小时、2小时孕酮水平出现轻微波动.但总的水平还很低,产后12～24小时孕酮水平有一短期升高现象。     

不同月龄青年奶牛血浆性激素水平的比较

采用放射免疫分析方法,测定了16头15至19月龄青年奶牛发情周期血浆中孕酮、17β—雌二醇和睾酮的含量。结果表明,15、16、17及19月龄青年奶牛的三种性激素含量差异均不显著(P>0.05)。说明青年奶牛在15月龄时,其卵巢的内分泌功能就已经健全。     

屡配不孕的尾根脂积症奶牛外周血浆P_4和17β-E_2水平的变化

应用放射免疫分析方法(RIA),首次研究了13头屡配不孕的尾根脂积症(adipopexis of tail head,简称ATH)奶牛和14头非尾根脂积症(non-adipopexis of tail head,简称NATH)奶牛外周血浆孕酮(P_4)和17β-雌二醇(17β—E_2)的水平。结果表明:成年母牛在发情周期第5—17天、青年母牛在发情周期第7—17天的血浆P_4水平,在屡配不孕的ATH牛显著或极显著地低于NATH牛(P<0.05或P<0.01至P<0.001);成年母牛在发情周期第3—5天的血浆17β-E_2水平,在屡配不孕的ATH牛显著和极显著地高于NATH牛(P<0.05和P<0.01);成年母牛在发情周期第5—17天的血浆17β—E_2(pg/ml)/P_4(ng/ml)的比值,在屡配不孕的ATH牛显著或极显著地高于NATH牛(P<0.05或P<0.01至P<0.001)。青年母牛在发情周期第5—11天的血浆17β—E_2/P_4的比值,在屡配不孕的ATH牛较明显地高于NATH牛,到第13—17天,前者显著地高于后者(P<0.025)。根据上述结果,作者认为17β—E_2/P_4比例的失调是导致ATH牛早期胚胎死亡和附植失败,而表现为屡配不孕的重要原因。     

脱氢表雄酮对大鼠颗粒细胞激素生成的作用

为了探讨脱氢表雄酮(DHEA)对大鼠原代卵巢颗粒细胞激素生成及相关甾体生成酶的影响,采用机械法分离培养大鼠原代卵巢颗粒细胞,放射免疫分析法检测培养液中雌二醇、孕酮和睾酮的含量;Real-time PCR法检测类固醇代谢途径中3β-羟基固醇脱氢酶(3β-HSD)、17β-羟基固醇脱氢酶(17β-HSD)、CYP450 mRNA的表达变化。结果显示:10μmol/L DHEA处理48 h后可显著促进大鼠原代卵巢颗粒细胞雌二醇(P<0.05)、孕酮(P<0.01)和睾酮的分泌量(P<0.01);显著促进3β-HSD(P<0.01)和17β-HSD(P<0.05)mRNA的表达,CYP450 mRNA表达略有降低,但无统计学意义。说明外源性DHEA处理可能通过调节3β-HSD、17β-HSD和CYP450等相关酶的基因表达,进而影响大鼠原代卵巢颗粒细胞雌激素和雄激素的分泌。     

奶牛胎衣不下的防治措施

奶牛胎衣不下是分娩第三期(胎膜排出期)胎衣不能在8—12小时内自然排出,滞留在子宫内的一种常见奶牛产后期疾病。其特征主要是胎儿胎盘不能从母体胎盘腺窝中分离开来。子宫肌收缩无力或弛缓,仅见一少部分胎膜悬垂于阴门之外。胎衣不下的奶牛外周血浆孕酮含量增高,17β-雌二醇减少,催产素降低,使分娩第二期(胎儿排出期)与第三期的内分     

自制中药方剂对围产后期奶牛血浆IL-1β、IL-10含量的影响

为了评估本中药方剂对围产后期奶牛的保健情况,研究产后奶牛体内炎性细胞因子含量的变化,试验将30头正常分娩奶牛分为试验组和对照组,测定了奶牛在产后第3,7,14,21天血浆中白细胞介素(IL)-1β(IL-1β)、IL-10含量的变化情况。结果表明:试验组奶牛在产后第21天血浆中的IL-1β的含量显著高于对照组(P0.05);试验组奶牛在产后第7天血浆中的IL-10含量显著高于对照组(P0.05)。说明此中药方剂对奶牛血浆中部分细胞因子有明显的调节作用,对正常分娩奶牛有一定的产后保健效果。     

LRH—A对母驼排卵和受胎效果的影响

为探求LRH—A诱导双峰母驼排卵、受胎效果,应用放射免疫法测定了母驼冷冻精液输精前后外周血清孕酮含量的变化。5峰(头)输精并肌注LRH—A母驼,输精前孕酮值平均为0.15±0.02ng/ml,输精后第3天增加到0.52±0.13ng/ml,第7 天可达1.62 ±0.89ng/ml。怀孕驼第12天孕酮仍维持高水平,为1.72±0.31ng/ml;而未怀孕驼孕酮水平7天开始下降,第12天降为0.32 ±0.06ng/ml(p<0.05)。5峰母驼受胎3峰,产羔3峰。3峰仅输冷冻精液的母驼,输精前后孕酮水平显著低于肌注LRH—A母驼排卵后的孕酮水平(p<0.05),均未受胎,持续发情。     

妊娠母猪细胞免疫水平及与孕酮、雌二醇关系的研究

采用非特异性酸性α醋酸萘酯酶(ANAE)染色、PHA诱导的淋巴细胞转化、放射免疫(RIA)测定等方法,测定了15头杜洛克杂种母猪第1胎产后断奶1～3d(未妊)及第2胎妊娠30～40d、41～50d、51～60d等不同时期的细胞免疫水平和外周血浆中孕酮、17β雌二醇含量。结果,未妊与不同妊娠期母猪之间T淋巴细胞百分率无明显差异(P>0.05);PHA诱导的淋巴细胞转化率,妊娠猪明显低于未妊猪(P<0.01),不同妊娠期间差异不显著(P>0.05);妊娠初期外周血浆17β雌二醇含量较低,孕酮含量明显高于未妊猪(P<0.01),不同妊娠期间差异不显著(P>0.05)。外周血浆孕含量与PHA诱导的淋巴细胞转化率之间存在着负相关(r=-0.51,P<0.01),表明孕酮具有免疫抑制作用。     

丙二醇对围产期奶牛能量平衡及代谢产物的影响

为了研究丙二醇对围产期奶牛能量平衡、血液指标和肝脏甘油三酯与糖原含量的影响。选用24头体质量(683.1±14.9)kg、胎次(2.5±0.2)、上一泌乳期305d产奶量(7 339±18)kg和预产期(24.5±0.2)d的经产奶牛,随机分为4组,从分娩前19d开始分别在基础日粮中添加丙二醇0、150、300和450mL.d-1。结果表明:与对照组相比,添加丙二醇300和450mL.d-1,显著提高了奶牛分娩后7、21和35d体况评分,缓减了奶牛体质量下降程度,改善了奶牛分娩前14d和分娩后7、21和35d奶牛能量平衡(P<0.05)。300和450mL.d-1组奶牛分娩前14d和分娩后7、21和35d血糖和胰岛素浓度显著高于对照组(P<0.05)。300和450mL.d-1组奶牛分娩后7、21和35d血浆游离脂肪酸、β-羟丁酸和甘油三酯浓度显著低于对照组(P<0.05)。300和450mL.d-1组奶牛分娩后7、21和35d肝脏甘油三酯含量显著低于对照组(P<0.05),但分娩后7、21和35d肝脏糖原含量显著高于对照组(P<0.05)。结果提示在日粮中添加丙二醇能够减少肝脏脂肪沉积,加强葡萄糖异生作用,改善奶牛能量平衡,适宜添加量为300mL.d-1。     

Effects of peripartum biotin supplementation of dairy cows on milk production and milk composition with emphasis on fatty acids profile

Forty Holstein dairy cows receiving a 38% concentrate diet based on maize silage were assigned to either a control group, either a biotin group, receiving 20 mg of biotin per day from 15 days before expected calving date and for 120 days after calving. Milk production was measured daily, milk fat content, protein content, urea and somatic cell counts were determined weekly from week 2 to week 17 of lactation. The profile of milk fatty acids was determined at weeks 3 and 10. Plasma glucose and blood beta-hydroxybutyrate were determined before calving and at weeks 1, 2, 3, 5, 7 and 10 of lactation.

Biotin supplementation resulted in an increased milk production in multiparous cows during weeks 2 to 6, but the effect was no more significant between 7 and 17 weeks of lactation. Milk protein percent was decreased by 0.1% in multiparous cows. Milk fat content was not affected by biotin, and milk fat daily production tended to increase during early lactation. In milk fat, biotin supplementation tended to decrease the proportion of fatty acids with less than 16 carbons at week 3, but the daily amount was not affected. Biotin tended to decrease biohydrogenation intermediates, increased C16:1 at week 3, and tended to increase cis-9 C18:1 at weeks 3 and 10. After 7 weeks of lactation, biotin tended to increase blood beta-hydroxybutyrate in multiparous cows with values remaining in a normal range, and decreased plasma glucose in primiparous cows. These modifications of plasma parameters, milk protein content and profile of milk fatty acids could be due to a higher lipid mobilisation from adipose tissue driven by the increased milk production.     

Neutrophil function and energy status in Holstein cows with uterine health disorders

The objectives of this study were to investigate the associations between peripheral blood neutrophil (PMN) function, energy status, and uterine health in periparturient dairy cows. Data were collected from 83 multiparous Holstein cows. Blood samples for PMN function determination were collected weekly from 1 week prior to calving (week -1) through 4 weeks after calving and again at 8 weeks after calving. Energy metabolites were measured and dry matter intake (DMI) was determined from weeks -2 to 5 to evaluate energy status of cows during the periparturient period. All cows were examined for uterine health disorders. Blood PMN killing ability was evaluated by determining myeloperoxidase activity and cytochrome c reduction activity in isolated blood PMN's. For cows that were diagnosed with puerperal metritis and subclinical (SC) endometritis and puerperal metritis, blood PMN functions were significantly (P<0.05) impaired during the periparturient period, compared to cows with normal uterine health. Cows with subclinical endometritis and puerperal metritis or SC endometritis also had significantly (P<0.01) higher NEFA and significantly (P<0.001) lower DMI during the periparturient period, and significantly (P<0.05) higher BHBA during early lactation, compared to cows with normal uterine health. Neutrophil function was also significantly (P<0.01) impaired in cows with peripartum negative energy balance, which was characterized by elevated blood levels of NEFA and decreased DMI. Decreased PMN function and energy balance were associated with uterine health disorders and the decreases in PMN function and energy balance occurred prior to parturition and prior to the detection of these uterine disorders.     

Post partum subclinical hypocalcaemia and effects on ovarian function and uterine involution in a dairy herd.

Episodes of subclinical hypocalcaemia occurred in the first 6 weeks after calving in 6 out of 12 multiparous Friesian cows calving in the winter period and 7 out of 23 calving in the summer in a subtropical environment. In the winter calving group, there were significant (P< 0.05) decreases in mean plasma calcium concentrations (PTCa) on days 6, 27 and 36 after calving in those animals unable to maintain PTCa >2.0 mmol/L in the first 21 days. These cows had a significantly higher mean body weight and higher mean milk production than normocalcaemic cows. In the summer calving group, the seven cows with episodes of subclinical hypocalcaemia had significantly lower mean PTCa over periods of 21 and 60 days. Intervals until involution of the uterus were negatively (P< 0.05) correlated with mean PTCa over the first 21 and 30 days after calving in the winter and summer calving groups (r = -0.62 and -0.42), respectively. The mean size of the first ovulated follicles was significantly smaller in cows showing episodes of subclinical hypocalcaemia in the winter group and the mean number of ovulatory size follicles was less in these cows at 15 days (P< 0.001) (1.2 +/- 0.17 vs 2.3 +/- 0.21) and at 30 days (P< 0.03) (3.5 +/- 0.43 vs 5.2 +/- 0.54). During the first three dioestrus periods, mean plasma progesterone concentration as a function of corpus luteum area was significantly lower (P< 0.05) in the cows with episodes of subclinical hypocalcaemia in the winter group.     

Sequential changes in plasma progesterone, total oestrogens and corticosteroids in cow throughout pregnancy and around parturition

Blood samples were taken thrice a week for 2 weeks from 33 pregnant cows in 9 groups, 1 month apart. In addition, blood samples were collected twice daily 1 week from 8 cows before parturition. Plasma progesterone and total oestrogens were quantified by validated radioimmunoassays and total corticosteroids by a competitive protein binding technique. During the 1st 3 month of pregnancy, no remarkable changes were observed from the 3 hormones studied. From the 4th month on, concentrations of progesterone and total corticosteroids decreased significantly (P less than 0.05) and remained fairly constant until the 9th month. Values of total oestrogens increased significantly (P less than 0.05) from the 4th to 6th months and stayed unchanged afterwards. Progesterone levels in periparturient cows decreased linearly (P less than 0.01) during 3 days preceding delivery. Concentrations of total oestrogens rose sharply from day -5 and peaked at calving. Values of total corticosteroids increased dramatically on the 6th day and 24 hours before parturition. The results obtained suggest that in contrast to studies cited earlier plasma corticosteroids could play a key role for triggering parturition in cows.     

Sequential changes in plasma progesterone, total oestrogens and corticosteroids in the cow throughout pregnancy and around parturition

Blood samples were taken thrice weekly for 2 weeks from 33 pregnant cows in nine groups, 1 month apart, and twice daily for 8 days commencing 1 week before parturition from eight cows. Plasma progesterone and total oestrogens were quantified by validated radioimmunoassays and total corticosteroids by a competitive protein binding technique. During the first 3 months of pregnancy, no remarkable changes were observed for the three hormones studied. From the fourth month on, concentrations of progesterone and total corticosteroids decreased significantly (P less than 0.05) and remained fairly constant until the ninth month. Values of total oestrogens increased significantly (P less than 0.05) from the fourth to the sixth month and thereafter remained unchanged. In the periparturient cows, progesterone levels decreased linearly (P less than 0.01) during the 3 days preceding delivery. Concentrations of total oestrogens rose sharply from day -5 and peaked at calving. Values of total corticosteroids increased dramatically on the sixth day and also at 24 hours before parturition. These results suggest that, contrary to earlier studies, plasma corticosteroids could have a primary key role for triggering parturition in cows.     

Influence of body condition at calving and postpartum nutrition on endocrine function and reproductive performance of primiparous beef cows

The influences of body condition score (BCS) at calving and postpartum nutrition on endocrine and ovarian functions, and reproductive performance, were determined by randomly allocating thin (mean BCS = 4.4 +/- 0.1) or moderate condition (mean BCS = 5.1 +/- 0.1) Angus x Hereford primiparous cows to receive one of two nutritional treatments after calving. Cows were fed to gain either 0.45 kg/d (M, n = 17) or 0.90 kg/d (H, n = 17) for the first 71 +/- 3 d postpartum. All cows were then fed the M diet until 21 d after the first estrus. A replication (yr 2; M, n = 25; H, n = 23) was also used to evaluate reproductive characteristics. Concentrations of IGF-I, leptin, insulin, glucose, NEFA, and thyroxine were quantified in plasma samples collected weekly during treatment and during 7 wk before the first estrus. Estrous behavior was detected by radiotelemetry, and luteal activity was determined based on concentrations of progesterone in plasma. All cows were bred by AI between 14 and 20 h after onset of estrus, and pregnancy was assessed at 35 to 55 d after AI by ultrasonography. Cows that calved with a BCS of 4 or 5 had similar endocrine function and reproductive performance at the first estrus. During treatment, H cows gained BW and increased BCS (P < 0.01), and had greater (P < 0.05) concentrations of IGF-I, leptin, insulin, glucose, and thyroxine in plasma than M cows. However, during the 7 wk before the first estrus, plasma concentrations of IGF-I, leptin, insulin, glucose, NEFA, and thyroxine were not affected by time. Cows previously on the H treatment had a shorter (P < 0.01) interval to first postpartum estrus and ovulation, and a larger dominant follicle (P < 0.01) at first estrus, than M cows, but duration of estrus and the number of mounts received were not influenced by nutrient intake. Pregnancy rate at the first estrus was greater (P < 0.03) for H (76%, n = 38) than for M (58%, n = 33) cows. Increased nutrient intake after calving stimulated secretion of anabolic hormones, promoted fat deposition, shortened the postpartum interval to estrus, and increased pregnancy rate at the first estrus. Concentrations of IGF-I and leptin in plasma were constant during 7 wk before the first estrus, indicating that acute changes in these hormones are not associated with the resumption of ovarian function in primiparous beef cows.     

Aspects of the metabolism of dairy cows during the incubation of bovine spongiform encephalopathy

As part of a nutritional study lasting from six weeks before calving to 22 weeks of lactation, blood samples collected from 47 dairy cows maintained under well-defined conditions were analysed for a variety of metabolites and hormones. At various times after the completion of the study, six of the animals developed clinical signs of bovine spongiform encephalopathy (BSE), although when they were sampled it was not known that they were incubating the disease. The data were used to make comparisons between the animals that developed BSE and those that did not develop the disease and which had been maintained under the same conditions. The greatest differences between the animals incubating BSE and the control animals were observed at times of nutritional stress, at the start of lactation and when the intake of concentrate feeds was reduced at week 13 of lactation. In the animals that subsequently developed BSE, feed intakes were lower in early lactation; plasma beta-hydroxbutyrate concentrations were significantly higher (P<0.001) at weeks 3 and 5 of lactation; adjusted milk yields were lower until week 6 of lactation and milk fat concentrations were consistently lower. There was no effect on plasma glucose concentrations, although insulin concentrations were significantly lower in week 1 of lactation (2-27 v 2.50 microiu/ml) (P<0.05). The concentrations of plasma proteins and urea were unaffected by BSE incubation, apart from protein concentrations being significantly higher one week before calving, and the concentration of urea being significantly lower five weeks before calving. The plasma concentrations of somatotrophin, prolactin, oestradiol and progesterone were similar in the two groups of animals throughout the study. The differences observed indicate that the energy metabolism of dairy cows incubating BSE may be subtly altered before the onset of clinical signs of the disease.     

Effects of human chorionic gonadotrophin and castration on plasma gonadal steroid hormones of the dog

An intramuscular injection of 500 I.U. of human chorionic gonadotrophin resulted in an increase of plasma testosterone and progesterone concentrations in the intact male dog, but had no effect on plasma 17B-estradiol concentration. Castration caused a rapid decrease in concentration of testosterone, progesterone, and 17B-estradiol, indicating that the tests were the major organs producing these hormones in the male dog.     

Body condition and frequency of ovarian cysts in Brown Swiss cows during the first 40 days of lactation

For this investigation 50 Brown Swiss cows from 21 different farms were used. Twenty-five peripartal overconditioned cows (back fat thickness > 38 mm) were compared with 25 peripartal not overconditioned animals (back fat thickness < 38 mm). On days 20, 30 and 40 post partum the ovaries were examined sonographically and 10, 15, 20, 30 and 40 days after calving plasma concentrations of progesterone and 17-beta estradiol were determined. In peripartal overconditioned animals 12 ovarian cysts were found while only one cyst was present in not overconditioned cows (P < 0.05). At first examination all ovarian cysts were classified by ultrasound as follicle theca cysts (progesterone < 0.5 ng/ml plasma). Follow examinations resulted in 3 cysts which persisted as theca cysts while 8 cysts became luteinized and 2 cysts completely regressed. There was no indication of increased plasma progesterone and/or estradiol concentrations in overconditioned cows with higher fat deposit before of ovarian cysts had occurred.     

The effects of duration and concentration of plasma progesterone on the fertility of post-partum cows treated with pregnant mare serum gonadotrophin and intravaginal progesterone

The effects of duration of insertion of progesterone releasing devices (PRIDs) on the concentrations of plasma progesterone (plasma P4) and the relationship of these with fertility were examined respectively in ovariectomised and intact Bos taurus cattle. In experiment 1, ovariectomised cows (n = 14) were treated with PRIDs to produce high and low plasma P4 for 7 or 14 days giving 4 treatment groups designated H7, H14, L7 or L14. Mean plasma P4 in the H14 and L14 groups were 6.6 and 6.0 ng/ml respectively, during the first week and 5.4 and 3.8 ng/ml respectively, during the second. Mean plasma P4 of 6.3 and 4.2 ng/ml were observed in H7 and L7. In experiment 2, suckled cows (n = 171) received the same PRID treatments as cows in experiment 1, plus either 375 or 750 iu pregnant mare serum gonadotrophin, and subsequent calving rates were recorded. These were significantly lower after L7 than the other treatments (12% v 38%, P less than 0.025). These results showed that fertility after oestrus was closely related to plasma P4 observed before oestrus and indicated that treatment with progesterone for as little as 1 week can produce normal fertility providing plasma P4 attain a critical threshold during treatment.