Bovine ovarian follicular cysts: in vitro effects of lecirelin, a GnRH analogue

This study investigates the mechanisms of action by which a GnRH analogue may modulate the contractility of the bovine ovarian follicular wall. The in vitro evaluation of the spontaneous basal contractility of bovine preovulatory and cystic follicles was performed, followed by testing the effects of lecirelin, a GnRH analogue, on their basal contractility. Strips of tissue in isolated organ bath were employed.In addition, to better investigate the mechanism of action of lecirelin, the study of the effects of cumulative doses of nifedipine (a calcium channel blocker), phentolamine (an α-adrenoceptor antagonist) and reserpine (an inhibitor of the vesicular up-take of catecholamines) alone and, at the highest doses employed, associated to lecirelin, was set up.The results demonstrate that in basal conditions and after the addition of lecirelin, the strips from preovulatory follicles contract significantly more than strips from cysts.Furthermore, among the patterns of contractility evoked by the three drugs employed, the one induced by nifedipine was the only one unaffected by the addition of lecirelin.The data obtained provide the hypothesis that one of the main mechanisms of action of GnRH, could involve calcium channels.     

Ecological effects of cow manure compost on soils contaminated by landfill leachate

The experiment was conducted to evaluate the effect of cow manure compost (CMC) application on leaching toxicity of leachate polluted soils by using Tetrahymena pyriformis (TP). Soils treated with various levels of leachate (0, 12.5 ml, 25 ml, 37.5 ml, and 50 ml leachate per 300 g soil) were amended with 0, 25 g and 50 g CMC, respectively. The results showed CMC application resulted in 7–18% lower leaching toxicity while excessive CMC has no significant benefit for decreasing leaching toxicity further. The alleviating effect of CMC on biotoxicity of soil extract was mainly attributed to either pH increase, high content of P and organic matter, or promotion on soil microbial metabolism and especially pH played an important role in alleviating effect. And the observations indicated that death rate (DR) of TP was more sensitive to leachate level respect to other biological parameters above and TP was effective as the test organism for leaching toxicity. Further studies are needed to unambiguously determine in-deep mechanism of toxicity impacts on TP posed by leachate pollutants.     

Novel Opioid Peptide Amidorphin: Characterization and Distribution of Amidorphin-Like Immunoreactivity in Bovine, Ovine, and Porcine Brain, Pituitary, and Adrenal Medulla

We have recently isolated from bovine adrenal medulla a novel C-terminally amidated opioid peptide, amidorphin, which derives from proenkephalin A. Amidorphin revealed a widespread distribution in bovine, ovine, and porcine tissue. Particularly high concentrations of amidorphin immunoreactivity were detected in adrenal medulla, posterior pituitary, and striatum, similar to the major gene products of proenkephalin A. In the adrenal medulla of each species, authentic amidorphin was the predominant immunoreactive form. Pituitary and brain, however, contained predominantly putative N-terminally shortened fragments of amidorphin of a slightly lower molecular weight and shorter retention times on HPLC. In addition, in ovine adrenal medulla, a putative high-molecular-weight form of amidorphin was detected. These findings are indicative of a tissue-specific processing of the proenkephalin A precursor, leading predominantly to authentic amidorphin in the adrenal medulla and further processing to smaller C-terminal fragments in the brain and pituitary.     

Liquid supplementation of grazing cows and calves

One hundred and one Angus cows (average weight 614 kg) and their bull calves (average weight 213 kg) grazing improved summer pastures were used to determine cow and calf intake of liquid supplement, and its effect on forage intake and performance. Forty-seven pairs had access to a 410 g CP/kg DM molasses-based liquid supplement in an open feeder and 54 pairs were not supplemented. The study was conducted in southwestern Montana from July 28 to October 3, 1997. Cows consumed significantly more supplement (0.3 kg/day) than calves (0.1 kg/day) but both consumed 0.5 g/kg bodyweight per day. Supplemented cows gained 0.12 kg/day more (p<0.05) than unsupplemented cows; however, there was no difference (p>0.10) in body condition score change. Average daily gain by supplemented calves was 30% greater (p<0.01) than average daily gain by unsupplemented calves. Forage intake (g/kg body weight) by both supplemented cows and calves was 64% greater (p<0.01) than forage intake by unsupplemented cows and calves. There was no difference (p>0.10) in milk intake between supplemented and unsupplemented calves. There was no difference (p>0.10) in time spent at the supplement feeder between cows and calves, averaging 5.0 min/day. Time at the feeder was lowest for 7-year-old cows, intermediate for 6- and 8-year-old cows, and highest for 9-year-old cows (p<0.10). There was no difference (p>0.10) in supplement feeding bouts/day between age groups of cows. Calf liquid supplement intake (g/kg body weight) and time spent at the supplement feeder were similar to intake and time spent at the feeder by cows. Liquid supplementation increased forage intake and average daily gain by cows and calves grazing improved forages in late summer. The cost for additional weight gained by the supplemented calves was US$ 0.33/kg and October cattle prices in Montana were US$ 1.64/kg. Liquid supplementation was cost effective under the conditions of this study.     

Effect of xylazine,isoxsuprine, and lidocaine on Doppler sonographic uterine and umbilical blood flow measurements in cows during the last month of pregnancy

The maternal portion of the bovine placenta receives blood mainly from the uterine arteries (AUT) and the fetal portion from the umbilical arteries (AUM). Placental perfusion is crucial for fetal development and undergoes adaptive changes during pregnancy according to the fetal requirements. One goal of this study was to investigate changes in Doppler sonographic measurements of blood vessels that supply blood to the placenta in cows during the last 4 weeks of pregnancy. Another goal was to examine how these measurements are affected by three drugs commonly used in cows at the time of parturition. Nine cows underwent Doppler sonographic examination of the AUT ipsilateral and contralateral to the pregnant horn and one AUM three times per week during the last 4 weeks of gestation. This was followed by the randomized administration of one of the three following experimental drugs per day: isoxsuprine (200 mg/cow, iv), xylazine (2 mg/100 kg, iv), and lidocaine for epidural anesthesia (100 mg/cow). Doppler sonographic examination was repeated 30 minutes after medication. Maternal pulse rate increased during the study period (P < 0.001), and the diameter of the contralateral AUT was smaller in the last week before birth than in the two preceding weeks. The resistance index (RI) of the ipsilateral AUT was smaller in the last week than in the first 2 weeks of the study period. Uterine blood flow volume increased after isoxsuprine by 5% and after epidural anesthesia by 6% (both P ≤ 0.05) and decreased after xylazine by 10% (P < 0.001). Isoxsuprine was the only drug that elevated the blood flow volume in the AUM (P ≤ 0.05). Xylazine increased the RI of both AUT (both P < 0.001) and significantly reduced maternal and fetal pulse frequencies, whereas isoxsuprine significantly reduced the RI of both AUT and the AUM and increased maternal and fetal pulse frequencies. The results reported that Doppler sonographic measurements of uterine and AUM change little in the last month of pregnancy in the cow. Isoxsuprine and epidural anesthesia with lidocaine have the potential to improve uterine perfusion.     

Application of cattle placental stem cells for treating ovarian follicular cyst

BACKGROUNDHigh humidity and temperature in Taiwan have significant effects on the reproductivity of Holstein cattle, resulting in the occurrence of bovine ovarian follicular cyst (OFC). Because of economic loss from OFC, manual rupture and hormone injection have been advocated for the management of OFC. However, these incomplete treatments increase hormone resistance in cattle. Mesenchymal stem cells (MSCs) derived from placental stem cells (PSCs) demonstrate potential properties for the treatment of several diseases via promoting angiogenesis and immune modulation. AIMTo establish the possibility of cattle placental stem cells (CPSCs) as a treatment modality for OFC of cows in Taiwan. METHODSThe cows with OFC were divided into three groups: control (BC1 and BC2), hormone (H1 and H2), and CPSC (PS1 and PS2) treatment groups. In the hormone treatment group, the cows were given gonadotrophin-releasing hormone (GnRH)-prostaglandin-GnRH intramuscular injection with or without drainage of follicular fluid. In the CPSC treatment group, CPSCs were isolated from the placenta after labor. With the identification of surface antigen on stem cells, the cows were administered ovarian injection of 1 × 10⁶ or 6 × 10⁶ CPSCs with drainage. In all groups, OFC was scanned by ultrasound once a week for a total of seven times. The concentrations of estradiol and progesterone in serum were tested in the same period. The estrus cycle was analyzed by food intake and activity. If estrus was detected, artificial insemination was conducted. Then the cow was monitored by ultrasound for confirmation of pregnancy.RESULTSAfter 7 d of culture, CPSCs were successfully isolated from placental pieces. CPSCs significantly proliferated every 24 h and had high expression of MSC markers such as cluster of differentiation 44, as determined by flow cytometry. Ultrasound showed lower numbers of OFCs with drainage of follicular fluid. We achieved recovery rates of 0%, 50%, 50%, 75%, 75% and 75% in BC1, BC2, H1, H2, PS1, and PS2, respectively. Higher concentrations of progesterone were detected in the CPSC treatment groups. However, both hormone and CPSC treatment groups had no significant difference in the concentration of estradiol. The estrus rate was 0%, 100%, 25%, 75%, 75% and 75% in BC1, BC2, H1, H2, PS1, and PS2, respectively. The two fetuses were born in H2 and PS1. In brief, cows with CPSC injection achieved higher recovery, estrus, and inseminated conception rates.CONCLUSIONCPSCs have efficacy in treating cows with OFC, and thus, may serve as an alternative treatment for reproductive disorders.     

Localization of mammary-derived growth inhibitor in capillary endothelial cells of the bovine mammary gland

Mammary-derived growth inhibitor (MDGI) has previously been localized in the mammary parencyma, dependent on the stage of differentiation of the mammary gland. Here, we have elucidated the distribution of MDGI in the mammary stroma by a combined immunohisto-and cytochemical analysis with antibodies raised against MDGI. Distinct staining of capillary endothelial cells has been revealed. Although its subcellular distribution resembles former observations in secretory epithelial cells, the expression of MDGI in capillary endothelial cells clearly precedes that in secretory epithelial cells. On the other hand, no endothelial MDGI staining has been detected in bovine heart, which contains a fatty acid-binding protein almost identical to MDGI. The localization of MDGI in the mammary capillary endothelium is discussed in terms of its possible involvement in the intracellular transport of hydrophobic ligands or in the regulation of endothelial cell proliferation.     

Numerical simulation of flow field around a cow using 3-D body-fitted coordinate system

A 3-D theoretical model that characterizes the flow field around a single cow or multiple cows was developed. A general computer code that simulates the flow field that takes into account the shape of a cow and the boundary conditions of the enclosure was developed. A system of visualization of flow field that provides theoretical basis for the study of heat and mass transfer between a cow and its environment was developed. Qualitative and quantitative analyses were performed to determine the effect of cow orientation with respect to direction of airflow on convective heat exchange between the cow and its environment. The direction of air movement is not an important factor in influencing convective heat transfer between a cow and its environment.