Effect of Insemination–Ovulation Interval and Addition of Seminal Plasma on Sow Fertility to Insemination of Cryopreserved Sperm

In swine, the use of frozen-thawed (FT) sperm for artificial insemination (AI) is limited because of poor sow fertility, possibly associated with a post-thaw capacitation-like status resulting in fewer fully viable sperm. Sow fertility to AI with FT sperm may improve with deeper deposition of sperm within the female tract, insemination very close to ovulation, or reversal of cryocapacitation by seminal plasma (SP). We performed two experiments to examine these suggestions. In experiment 1, 122 multiparous Yorkshire sows received 600 IU equine chorionic gonadotrophin at weaning and 5 mg pLH 80 h later to control time of ovulation. The predicted time of ovulation (PTO) was 38 h after pLH injection. Thereafter, sows were assigned on the basis of parity to a single AI of FT sperm at 2 h before PTO, or at 12 h before PTO, or FT sperm supplemented with 10% SP at 12 h before PTO. Control sows received fresh semen at 12 h before PTO. All semen doses were adjusted to 3 x 10(9) live cells and deposited into the cervix. Experiment 2 employed 99 multiparous crossbred sows and repeated the treatments of experiment 1 except that all FT inseminations were intrauterine. In both experiments, farrowing rates were lower (p < 0.01) following FT inseminations with no effect of time of insemination or of supplemental SP. In experiment 1, litter size was smaller following FT insemination (p < 0.05), but no effect on litter size was evident in experiment 2. Supplemental SP had no effect on litter size in either experiment. The lack of effect of either SP or timing of FT insemination on sow fertility suggests that the non-lethal sperm cryoinjury affecting fertility involves more than just cryocapacitation.     

Uterine Responses to Exogenous Oxytocin Before and After Pre-partum Luteolysis in the Cow

The aim of this study was to test the functional status of uterine oxytocin receptors in cows in vivo around parturition. The animals received consecutive, intra‐arterial injections of 800, 1600 and 3200 mU of oxytocin at three different stages: during late gestation (days 260–274), at 12 h and at 24 h after intramuscular injection of a prostaglandin F_2α analogue at day 275 to induce parturition. Cows (n=6) had been provided with myometrial electrodes and a catheter had been installed in the aorta and in a branch of the uterine vein (UV). Regular blood samples were obtained from the UV from 5 min before until 45 min after each oxytocin injection to measure plasma levels of prostaglandin F_2α (PGF_2α) and oxytocin. Uterine electromyographic (EMG) activity was registered continuously during each experiment. The increase of oxytocin levels in UV plasma after intra‐arterial injections was dose dependent (p < 0.02). Pre‐ and post treatment oxytocin levels at 24 h after induction of parturition were significantly increased (p=0.0313). Both during late pregnancy and at 12 h after induction of parturition, oxytocin caused a significant increase in EMG activity (p=0.022). After the 3200 mU dose the increase was significantly higher than with the other 2 doses (p=0.004). After each dose, EMG activity returned to baseline levels within some 15 min. At 24 h after induction of parturition, the pre‐treatment level of EMG activity had increased. Doses of 800 mU and 1600 mU of oxytocin produced a significant (p=0.022) increment of EMG activity, which was of the same magnitude as during the preceding stages; after 3200 mU of oxytocin the response was significantly higher than before (p=0.008). No significant increases of PGF_2α levels in UV plasma could be measured after oxytocin injections at any of the three stages. It is concluded that the myometrium of the pregnant cow responds in vivo to physiological doses of oxytocin. At 24 h after induction of parturition, when luteolysis has occurred and a parturient pattern of parturient myometrial activity has already started to develop, the response is enhanced. Physiological doses of oxytocin did not evoke a spurt release of PGF_2α in uterine venous blood during the peripartal period.     

Expression of Nociceptive Ligands in Canine Osteosarcoma

Background

Canine osteosarcoma (OS) is associated with localized pain as a result of tissue injury from tumor infiltration and peritumoral inflammation. Malignant bone pain is caused by stimulation of peripheral pain receptors, termed nociceptors, which reside in the localized tumor microenvironment, including the periosteal and intramedullary bone cavities. Several nociceptive ligands have been determined to participate directly or indirectly in generating bone pain associated with diverse skeletal abnormalities.

Hypothesis

Canine OS cells actively produce nociceptive ligands with the capacity to directly or indirectly activate peripheral pain receptors residing in the bone tumor microenvironment.

Animals

Ten dogs with appendicular OS.

Methods

Expression of nerve growth factor, endothelin‐1, and microsomal prostaglandin E synthase‐1 was characterized in OS cell lines and naturally occurring OS samples. In 10 dogs with OS, circulating concentrations of nociceptive ligands were quantified and correlated with subjective pain scores and tumor volume in patients treated with standardized palliative therapies.

Results

Canine OS cells express and secrete nerve growth factor, endothelin‐1, and prostaglandin E2. Naturally occurring OS samples uniformly express nociceptive ligands. In a subset of OS‐bearing dogs, circulating nociceptive ligand concentrations were detectable but failed to correlate with pain status. Localized foci of nerve terminal proliferation were identified in a minority of primary bone tumor samples.

Conclusions and Clinical Importance

Canine OS cells express nociceptive ligands, potentially permitting active participation of OS cells in the generation of malignant bone pain. Specific inhibitors of nociceptive ligand signaling pathways might improve pain control in dogs with OS.     

Factors Affecting the First Service Conception Rate of Cows in Smallholder Dairy Farms in Bangladesh

The successful outcome of an insemination is a combination of both male and female fertility‐linked factors. We investigated the first service conception rate of cows at artificial insemination (AI) in the smallholder dairy farms in Bangladesh. Frozen straws were prepared from ejaculates of Bos indicus (n = 7) and Bos indicus × Bos taurus (n = 7) AI bulls. Fertility was determined from 6101 first services in cows that were performed by 18 technicians in four regions between April 2004 and March 2005. Pregnancy was diagnosed by rectal palpation between 60 and 90 days post‐insemination. The Asian version of Artificial Insemination Database Application (AIDA ASIA) was used for bulls‐, cows‐ and AI‐related data recording, and later retrieved for analysis. The mean ± SD number of inseminations performed from individual bulls and their conception rates were 436.0 ± 21.6 and 50.7 ± 1.9%, respectively. Logistic regression demonstrated body condition scores (BCS), heat detection signs, months of AI and their interactions had greatest effects (odds ratios: 1.24–16.65, p < 0.04–0.001) on first service conception rate in cows. Fertility differed (p < 0.02–0.001) between the regions, previous calving months, months of AI, BCS, parity and heat detection signs of cows. Inseminations based on mounting activity (n = 2352), genital discharge (n = 3263) and restlessness and/or other signs (n = 486) yielded a conception rate of 53.6%, 48.8% and 50.1%, respectively (p < 0.05). Conception rate between technicians ranged between 43.4% and 58.6% (p < 0.05). The days interval from calving to first service (overall mean ± SD = 153.4 ± 80.6) had relationship (p < 0.001) with BCS, months of previous calving and parity of the cows. Fertility at AI in smallholder farms can be improved by training farmers on nutrition and reproductive management of the cows.     

Effect of metribuzin, butachlor and chlorimuron-ethyl on amino acid and protein formation in wheat and maize seedlings

Application of the recommended field dose of metribuzin, butachlor and chlorimuron-ethyl to 10-days-old wheat and maize seedlings differentially reduced shoot fresh and dry weights during the following 16 days. Metribuzin was the most reductive while butachlor was the least. The herbicides slightly affected the activities of nitrate reductase (NR, EC 1.6.6.1) and nitrite reductase (NiR, EC 1.7.7.1) but greatly inhibited glutamine synthetase (GS, EC 6.3.1.2) and glutamate synthase (GOGAT, EC 1.4.7.1) activities. Meanwhile, there were significant accumulations of ammonia and soluble-N accompanied by diminutions in total-N and protein contents; metribuzin exerted the greatest changes. Additionally, aliphatic, aromatic and total amino acids in both species were mostly elevated by the three herbicides; however, valine, leucine and isoleucine were decreased by only chlorimuron-ethyl. These results could conclude that herbicides, particularly metribuzin, cause a shortage in ammonia assimilation and subsequently a decrease in protein formation. Moreover, the elevation of soluble-N and amino acids appeared to result from breakdown of the pre-existing protein, a state that seemed consistent in seedlings treated with metribuzin and, to some extent chlorimuron-ethyl but recovered in those treated with butachlor.     

Physiological and biochemical responses to low non-freezing temperature of two Eucalyptus globulus clones differing in drought resistance

We have compared the metabolic responses of leaves and roots of two Eucalyptus globulus L. clones CN5 and ST51 that differ in their sensitivity to water deficits (ST51 is more drought sensitive), with regard to the effect of chilling (10/5 °C, day/night). We studied changes in growth, osmotic potential and osmotically active compounds, soluble proteins, leaf pigments, and membrane lipid composition. Our data showed that both clones have the ability to acclimatize to chilling temperatures. As a result of 10 days of acclimation, an increase of soluble sugars in leaves of treated plants of both clones was observed that disappeared later on. Differences between clones were observed in the photosynthetic pigments and soluble protein content which were more stable in CN5 under chilling. It also was apparent that CN5 presented a less negative predawn water potential (ψ_pd) and a higher leaf turgor than ST51 throughout the chilling treatment. In the case of the CN5, increased total lipids (TEA) and concomitant increase of linolenic acid (C18:3) in leaves after acclimatization may be related to a better clone performance under chilling temperatures. Moreover, a higher constitutive investment in roots in the case of CN5 as compared to ST51 may benefit new root regeneration under low temperatures favoring growth after cold Mediterranean winter.     

Four New Sulfated Polar Steroids from the Far Eastern Starfish Leptasterias ochotensis: Structures and Activities

Three new sulfated steroid monoglycosides, leptaochotensosides A–C (1–3), and a new sulfated polyhydroxylated steroid (4) were isolated from the alcoholic extract of the Far Eastern starfish Leptasterias ochotensis. The structures of compounds 1–4 were established by extensive nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESIMS) analyses and chemical transformations. Although the isolated compounds did not show any apparent cytotoxicity against melanoma RPMI-7951 and breast cancer T-47D cell lines, leptaochotensoside A (1) demonstrated inhibition of T-47D cell colony formation in a soft agar clonogenic assay at nontoxic doses. In addition, this compound decreased the epidermal growth factor (EGF)-induced colony formation of mouse epidermal JB6 Cl41 cells. The cancer preventive action of 1 is realized through regulation of mitogen-activated protein kinase (MAPK) signaling pathway.     

Environmental and maternal factors associated with gross placental morphology in dairy cattle

This article reports on a study of gross placental morphology of 282 expelled placentas from 89 primi‐ and 193 multiparous Holstein dams immediately after calving and examines associations with environmental factors such as typical herd features and season of calving, and maternal factors such as age at calving, level of milk yield at conception and cumulative amount of milk produced during gestation. The highest correlation between calf measurements and placental characteristics was found between the weight of the calf and the total cotyledonary surface (r = .643; p < .001), confirming the high importance of the cotyledonary surface available for nutrient transfer to the developing foetus. Younger age in adolescent and smaller heart girth in multiparous dams were associated with a higher cotyledon number, suggesting placental compensation in dams with lower capacities in terms of dry matter intake. No significant association between milk yield during gestation in multiparous animals and gross placental morphometrics could be detected, indicating that factors such as the amount of milk produced during gestation affect placental development less than foetal weight close to term. Therefore, placental growth may be sustained at the expense of other tissues in an attempt to maintain pregnancy and minimize the adverse consequences for the foetus. This study offers evidence concerning factors affecting the placental surface size for nutrient transfer from dam to calf in dairy cattle based on gross morphometrics, but needs confirmation from studies in which this surface size is more profoundly assessed by measuring the branches present in the cotyledonary villi.