Common epithelial tumours of the ovary in cows

A morphological study of the epithelial tumours diagnosed during examination of 1489 cows slaughtered in León, Spain was carried out. Epithelial neoplasms were observed in four animals which represents an incidence of 0.27 per cent. So far as the authors are aware it is the first time that two serous papillary cystadenomas and one serous superficial papilloma have been described in cows. The fourth neoplasm was a mucinous cystadenoma.     

Changes in the ovary and the peripheral concentrations of sex hormones after the aspiration of follicular fluid from the spontaneous follicular cysts of dairy cows

The aim of the present study was to clarify the ovarian and hormonal dynamics after the aspiration of follicular fluid in cows with follicular cysts. Follicular fluid was aspirated from the follicular cysts and follicles that were fated to become cystic follicles and other coexisting normal follicles, respectively, in lactating cows (n = 3). After the aspiration procedure, new follicles developed and reached a diameter of 25 mm without ovulation within 13–19 days. The plasma concentrations of inhibin decreased and follicle-stimulating hormone increased rapidly after the aspiration procedure, and subsequently increased and decreased, respectively, as a new follicle grew. No luteal structures developed after the aspiration procedure, and the animals’ plasma progesterone levels remained low. The present study indicates that the cystic follicles are never luteinized by the aspiration of follicular fluid, and consequently, new follicular cysts are observed to repeatedly develop.     

Production of estradiol by each ovary during the estrous cycle of cows

The objective of our experiment was to examine changes in serum concentrations of estradiol in each utero-ovarian vein before, during and after gonadotropin surges. Four cows were given prostaglandin F2 alpha (PGF2 alpha) during diestrus and three cows were allowed to cycle spontaneously. All cows had a cannula in each utero-ovarian vein and in one jugular vein. Most cows had two transient rises in estradiol, primarily coming from a single ovary, preceding and after luteinizing hormone (LH) surges. The first rise in estradiol began after luteal regression and was sustained from 48 h before a pre-ovulatory LH surge to the end of the LH surge. The second rise in estradiol was sustained from 72 to 168 h after the end of an LH surge. To determine how rapidly asymmetrical production of estradiol began during luteolysis, several cows were injected with PGF2 alpha during the luteal phase. Blood samples were taken from a jugular and both utero-ovarian veins at hourly intervals before and after PGF2 alpha. Asymmetrical production of estradiol began within 3 h after an injection of PGF2 alpha. We concluded: (1) that a single ovary was responsible for the sustained increases in concentration of estradiol that occur during proestrus to estrus and early diestrus in cows and (2) that cows may have at least one follicle capable of producing estradiol during most days of an estrous cycle, thus little delay in selection of which follicle eventually ovulates occurs after luteal regression.     

Changes of cyclic AMP levels and phosphodiesterase activities in the rat ovary

Cyclic AMP (cAMP) is a second messenger that plays a critical role in follicular recruitment, development and luteinization in the mammalian ovary. The cellular level of cAMP is largely dependent on the activity of phosphodiesterase (PDE), which degrades cAMP into 5'-AMP. The present study was conducted to investigate the level of cAMP and the activity of cAMP-PDE in postnatal rats; immature rats during gonadotropin-primed follicular development, ovulation and luteinization; adult rats during normal estrous cycling; and aged rats that spontaneously developed persistent estrous (PE) by radioimmunoassay (RIA). All four rat models were confirmed by histological examination of one ovary and assayed using the other ovary by RIA. In the postnatal rats, the ovarian cAMP level was high on day 10 after birth, while ovarian cAMP-PDE activity was highest at 21 days of age. In the immature female rats, both the ovarian cAMP level and cAMP-PDE activity increased remarkably after treatment with equine chorionic gonadotropin (eCG), increased continuously 24 h after injection of human chorionic gonadotropin (hCG) for induction of ovulation and luteinization, and then declined significantly. In the adult rats during the normal estrous cycle, the ovarian cAMP levels were low on the day of estrus, and there were no significant changes in ovarian cAMP-PDE activity throughout the estrous cycle. In the PE rats, the ovarian cAMP levels were similar to those of the adult rats on the day of estrus but were lower than those on the other days of the estrous cycle; ovarian cAMP-PDE activity was lower than that in the adult rats on any day of the estrous cycle. Together, these findings indicate that the ovarian cAMP level and cAMP-PDE activity were regulated in a stage-dependent manner during ovarian follicular development, atresia and luteinization and providing evidences that cAMP and cAMP-specific PDEs are involved in these physiological processes.     

Changes in electrical resistance of the vaginal mucosa in prostaglandin-treated cows

Ten Hereford x Friesian cows each received 1 mg fenprostalene by a single subcutaneous injection between days 5 and 16 of their ovarian cycles and the treatment was repeated 17 days later. The cows' ovarian cycles were monitored by daily plasma progesterone measurements, and the electrical resistance of their vaginal mucosae was also measured daily, with a Wallsmeta. Luteolysis occurred after 13 of the 20 injections of fenprostalene, and vaginal resistance measurements corresponded to changes in progesterone concentrations in 14 of the 20 potential luteolytic periods. Vaginal resistance measurements decreased in three cases where progesterone concentrations did not decrease (false positive results) and failed to decrease in three cases where progesterone concentrations did decrease (false negative results).     

Influence of the ovary and suckling on luteinizing hormone response to naloxone in postpartum beef cows

The influence of the suckling stimulus and ovarian secretions on LH response to naloxone was studied in 16 postpartum anestrous beef cows that were assigned randomly to one of four groups (n = 4/group): intact suckled (IS), intact nonsuckled (IN), ovariectomized suckled (OS) or ovariectomized nonsuckled (ON). Ovariectomy (OS + ON) and calf removal (IN + ON) were performed on d 2, 3 or 4 after parturition. Jugular venous blood was collected at 15-min intervals for 4 h before and 4 h after administration of naloxone (1 mg/kg BW, i.v.) on d 14 and d 28 after parturition. Gonadotropin-releasing hormone (5 micrograms, i.v.) was given 3 h after naloxone. Both IN and OS increased (P less than .05) mean pretreatment LH above IS values (mean +/- SE, ng/ml; IS 1.6 +/- .1 vs IN 2.5 +/- .3 and OS 2.7 +/- .4; P less than .01), whereas ON increased (P less than .01) LH (3.7 +/- .3 ng/ml) even further. Mean LH increased (P less than .05) after naloxone administration in all treatment groups. However, magnitude of this response was variable and dependent on ovarian status. Amplitude of the naloxone-induced LH response was greater (P less than .05) for ovariectomized (5.9 +/- 1.1 ng/ml) than for intact groups (2.7 +/- .5 ng/ml). Gonadotropin-releasing hormone increased mean LH concentrations in all groups. We suggest that ovarian secretions and the suckling stimulus contribute to endogenous opioid inhibition of LH during the postpartum interval.(ABSTRACT TRUNCATED AT 250 WORDS)     

乳房炎奶牛血清抗氧化相关指标的变化

为了探讨乳房炎对奶牛血清抗氧化相关指标的影响,随机选择48头泌乳期奶牛,比较正常奶牛与乳房炎奶牛血清中抗氧化酶、抗氧化维生素和微量元素的变化,进一步为奶牛乳房炎的发病机理、预防及控制提供研究基础。试验结果表明:乳房炎组奶牛血清中抗氧化酶中的过氧化氢酶(CAT)、总超氧化物岐化酶(T-SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性显著或极显著高于正常组(P0.05或P0.01);乳房炎组奶牛血清中Zn、Fe含量显著低于正常组(P0.05),而Cu含量与正常组差异不显著(P0.05);乳房炎组奶牛血清中V_C、V_E极显著低于正常组(P0.01)。这说明患牛体内Zn、Fe、V_C、V_E的显著下降在一定程度上影响乳房炎奶牛的康复。     

Changes in the serum levels of primary bile acids in dairy cows

Serum cholic acid (SCA) and serum chenodeoxycholic acid (SCDCA) concentrations were determined in healthy dairy cows by radioimmunoassay (RIA). The levels of these two primary bile acids were correlated with the cows' reproductive status. The lowest concentrations were measured in dry cows (SCA: 7.8 +/- 3.3 mumol/l, SCDCA.: 1.5 +/- 1.0 mumol/l). In freshly calved cows SCA and SCDCA was 17.8 +/- 6.9 mumol/l and 2.3 +/- 1.0 mumol/l, respectively, while in milking cows SCA and SCDCA was 15.8 +/- 5.7 and 2.3 +/- 0.8 mumol/l, respectively. SCA concentration showed a characteristic change on the days immediately after calving: on calving day it was close to the mean SCA concentration found for dry cows, then it underwent a striking abrupt rise and reached the value typical of post-parturient cows by post-partum (PP) day 4-5. Cholic acid was found to be the major primary bile acid in the blood of dairy cows. In dry cows the SCA:SCDCA ratio is 5:1. If the serum bile acid concentration rises, the SCA:SCDCA ratio will increase further.     

Changes of serum alkaline phosphatase activity in dry and lactational cows

Serum alkaline phosphatase (ALP) activities were measured during dry and lactational periods to investigate the influence of lactation on serum ALP activity in cows. Higher levels of serum ALP activity were seen in lactational periods than in dry periods. The serum activities of bone-specific ALP (BALP), liver ALP (LALP), tartrate resistant acid phosphatase (TRAP) and aspartate aminotransferase also increased in lactational periods. ALP activities in the bone extract and in whey were decreased at similar rates by the addition of lectin. Moreover, since the ALP band in whey was observed to have the same migration in polyacrylamide gel (PAG) disk electrophoresis as that of the bone extract, analysis of ALP isoenzymes by lectin affinity or PAG disk electrophoresis could not distinguish ALP originating from the mammary gland from that of bone. In this study, it was clear that the increased level of serum ALP activity was due to increases of BALP and LALP in lactational periods. However, the extent of the influence of ALP originating from the mammary glands on serum ALP activity was unknown. Judging from changes of BALP and TRAP activities in the serum and the correlation between the both, it was guessed that ALP originating from the mammary glands influenced serum ALP activity.     

血液能量平衡指标对高产奶牛产后卵巢静止的影响

本试验旨在确立能量平衡对奶牛产后卵巢静止的作用,为今后预防该病提供科学依据。从黑龙江省某集约化牛场随机选取产后14~21d奶牛80头(年龄2~4岁,胎次1~3次,泌乳量(34.82±9.51)kg/d),跟踪观测至产后60~90d,进行奶牛发情鉴定,结合B超观察与生殖激素检测从观测奶牛中选出卵巢静止与发情奶牛各16头。对2组奶牛产后14~21d和60~90d的血浆能量代谢及肝功能指标进行了统计比较。结果显示:产后60~90d卵巢静止奶牛血浆β-羟丁酸和游离脂肪酸含量高于发情奶牛(P0.05),血浆促卵泡素、雌二醇和孕酮浓度极显著低于发情奶牛(P0.01);根据受试者工作特征曲线分析确定产后14~21d血浆β-羟丁酸0.69 mmol/L、游离脂肪酸0.52mmol/L作为产后卵巢静止预警值,灵敏度和特异度分别为85.7%和83.30%,92.3%和86.70%,产后60~90d2项指标的预警值分别为0.42,0.17mmol/L。奶牛产后14~21d与60~90d血浆β-羟丁酸和游离脂肪酸浓度超过预警值,奶牛产后发生卵巢静止的风险会增大。     

Changes in blood composition of pregnant cows during the onset of hypomagnesaemia

Magnesium, calcium, phosphate, total protein and free fatty acid concentrations, and a lipase activity using p-nitrophenylpalmitate NP-C16) as a substrate, were determined in the serum of 15 pregnant Aberdeen Angus cows grazing a Phalaris tuberosa pasture with a tendency to induce tetany. A gradual decrease in magnesium concentrations, but no definite change in the other parameters, was observed when the results were plotted directly against the time of the experiment. When the results were plotted as a function of the stage of pregnancy or lactation of the animals, magnesium concentrations showed a more steady decrease which was associated with increases in calcium concentrations and, at the lowest magnesium concentrations, with increases in phosphate concentrations. Total proteins and free fatty acids remained fairly constant and the highest lipase activity was associated with parturition. The lowest magnesium concentrations in serum did not correspond with high levels of either lipase or free fatty acids. The hypomagnesaemia observed in this experiment was attributed to the high potassium:calcium and magnesium ratio in the pasture and to the physiological condition (pregnant and lactating) of the animals. None of the parameters evaluated in this paper would be more sensitive than serum magnesium levels for the early detection of the conditions that predispose grazing cattle to grass tetany.