Conception rate following artificial insemination with sexed semen in Holstein heifers under artificial cooling during summer compared with winter season

Tropical Animal Health and Production - The objective of this study was to compare the fertility of Holstein heifers under cooling and inseminated with sexed semen during the summer versus winter...     

Interactive responses of Quercus suber L. seedlings to light and mild water stress: effects on morphology and gas exchange traits

? The combined effect of water stress and light on seedlings of forest species is a key factor to determine the best silvicultural and afforestation practices in the Mediterranean area.

? The aims of this work was (1) to determine the optimal light level for the early development of cork oak seedlings under mild water stress and (2) to test if the combined effect of water stress and light followed the trade-off, the facilitation or the orthogonal hypothesis.

? Shade reduced instantaneous photosynthetic rates and water use efficiency in cork oak. However, seedlings grown under moderate shade (15% of full sunlight) were capable to accumulate similar amount of biomass than those grown under more illuminated environments by increasing their specific leaf area. Absolute differences in net photosynthesis between light treatments were higher in well watered than in water stressed seedlings. However, the impact of both factors on overall growth was orthogonal.

? We concluded that cork oak development is impaired under deep shade (5% of full sunlight) but it can be optimal under moderate shade (15% of full sunlight) even under moderate water stress. Implications of these patterns on regeneration, cultivation and afforestation of cork oak are discussed.

     

The effect of alkaloids and seed extracts of endophyte-infected tall fescue on prolactin secretion in an in vitro rat pituitary perfusion system.

The objective of this research was to measure the effects of endophyte-infected tall fescue seed extract and various alkaloids associated with the endophyte on in vitro prolactin secretion by rat hemipituitaries. Rat anterior pituitaries (AP) were dissected into halves and placed in temperature-controlled culture chambers (37 degrees C). The tissue was perfused with culture media at a flow rate of 12 mL/h. After perfusion for at least 90 min with control media, AP halves were exposed to their respective treatments for 15 min before they were returned to the control media. The treatments for Exp. 1 were .01 micrograms of alpha-ergocryptine/mL of culture medium, .01 microgram of ergonovine/mL of culture medium, .01 gram-equivalents of endophyte-infected tall fescue seed/mL of culture medium, and .01 gram-equivalents of endophyte free tall fescue seed/mL of culture medium. Treatments for Exp. 2 consisted of 10(-4), 10(-6), and 10(-8) M concentrations of perloline, N-formyl loline, N-acetyl loline, N-methyl loline, and alpha-ergocryptine. alpha-Ergocryptine suppressed (P less than .10) prolactin secretion in both experiments. Ergonovine and perloline both stimulated (P less than .10) prolactin secretion. The loline alkaloids (N-formyl loline, N-acetyl loline, N-methyl loline) had no effect on prolactin secretion. The endophyte-infected seed extract treatment suppressed (P less than .10) prolactin secretion. The endophyte-free seed extract treatment had no effect on prolactin secretion. In Exp. 2, prolactin secretion from AP responded to alpha-ergocryptine treatment in a dose-dependent fashion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Development of a multivariate yield grade equation to predict compositional traits in mature cow carcasses.

Data from 68 cow carcasses were used to develop a new yield grading system. First principal component (FPC) values for compositional attributes (LNFT = separable lean weight/[lean+fat weight] x 100, LNBN = separable lean weight/[lean+bone+connective tissue weights] x 100, and BTPR = [defatted lean from the round, loin, rib, and chuck]/side weight x 100) were determined. The first component explained 83.5% of the standardized variance and load values were .63, -.52, and .58, respectively. The resulting FPC values ranged from -1.93 to 1.89. The linear regression of LNFT, LNBN, and BTPR (dependent variables) on FPC (independent variable) explained a significant amount of variation (P less than .001) in each case and resulted in R2-values of .98, .67, and .85, respectively. A best-fit yield grade equation, developed to predict FPC, included adjusted fat thickness (ADF), percentage of kidney, pelvic, and heart fat (KPH), and overall muscling grade (OM). The equation, FPC = 2.04 - (.67 x ADF) - (.21 x KPH) - (.0016 x OM), explained a significant amount (P less than .001) of variation in FPC with R2 = .94 and residual standard deviation = .25. Simple correlations for ADF, KPH, and OM with FPC were -.87, -.71, and -.80, respectively. Cow carcasses were assigned to one of three grades based on FPC values that corresponded with predetermined levels of LNFT, LNBN, and BTPR. These grades generally had smaller CV than existing grades. When used in conjunction with quality grades, proposed grades could be more useful to the cow meat industry.     

The ultrastructure of oogenesis in Culex theileri

The 12-36 h post blood meal (PBM) oocyte in C. theileri is characterized by a dramatic increase in the quantity of protein with concomitant changes in the adjacent follicular epithelium. The cytoplasm shows a preponderance of mitochondria and rough endoplasmic reticulum in proportion to free ribosomes. Numerous Golgi complexes, which bud off secretory granules, are also found scattered in the cytoplasm. These changes are concerned with the deposition of the vitelline membrane and by 36 h PBM, a continuous vitelline membrane is formed at the follicle cell-oocyte interface. Vitellogenesis appears to be completed by 48 h PBM and the final maturation stages are concerned solely with deposition of the chorionic membrane. In C. theileri the chorionic membrane seems to be synthesized in a similar manner to the vitelline membrane; namely from the aggregation of secretory droplets and only proceeds once the vitelline membrane formation is completed. The chorionic membrane is made up of an endochorion and an exochorion. Although the structural complexity of the follicular epithelium is maintained at 48 h PBM, its appearance at 60 h PBM is indicative of degenerative changes. By 60 h PBM synthesis of both the vitelline and chorionic membranes has been completed and vitellogenesis has ceased. This stage then represents the complete maturation of the ovum in C. theileri.     

Comparison of cerebral cranium volumes between cavalier King Charles spaniels with Chiari-like malformation, small breed dogs and Labradors

O bjectives : To ascertain whether cavalier King Charles spaniels (CKCSs) have a proportionately smaller caudal fossa compared with other small dogs and with Labradors. To evaluate if cerebellar herniation in CKCS correlates with caudal fossa volume.
M ethods : In this retrospective study, three-dimensional images were created from magnetic resonance imaging brain series of 117 dogs (split into three groups: CKCS, Labradors and small breeds) from which the volumes of the fossae and brain parenchyma were calculated. These volumes were transformed into percentages of total cranial cavity and parenchyma volumes, respectively. The percentages were statistically compared among the groups. The percentage of herniated cerebellum in the CKCS was compared using linear regression with the caudal fossa and parenchyma percentages.
R esults : Cavalier King Charles spaniels had a proportionately smaller caudal fossa compared with Labradors (P=0·002) but not to small breeds (P=0·103). Their caudal fossa parenchyma was proportionately the same volume as Labradors (P=0·976) but greater than small breeds (P=0·005). No relationship was found for the per cent of cerebellum herniated.
C linical S ignificance : The results support mesoderm insufficiency or craniosynostosis as the pathogenesis of Chiari-like malformation (CM) in CKCS. It presents evidence for overcrowding of the caudal fossa due to a mismatch of brain parenchyma and fossa volumes as to why CKCS and not other small dogs are affected.     

Penetration of a topically applied nonsteroidal anti-inflammatory drug into local tissues and synovial fluid of dogs

OBJECTIVE: To investigate penetration of a topically applied nonsteroidal anti-inflammatory drug (NSAID) into tissues and synovial fluid. ANIMALS: 5 Greyhounds. PROCEDURE: Dogs were anesthetized and microdialysis probes placed in the dermis and gluteal muscle over each coxofemoral (hip) joint. Methylsalicylate (MeSA) was applied topically over the left hip joint. Dialysate and plasma (blood samples from the cephalic and femoral veins) were obtained during the subsequent 5 hours. Dogs were euthanatized, and tissue samples and synovial fluid were collected and analyzed for salicylic acid (SA) and MeSA by use of high-pressure liquid chromatography. RESULTS: SA and MeSA concentrations increased rapidly (< 30 minutes after application) in dialysate obtained from treated dermis. Salicylic acid also appeared in plasma within 30 minutes and reached a plateau concentration after 2 hours, although combined drug concentrations (SA plus MeSA) in plasma obtained from femoral vein samples were twice those measured in plasma obtained from the cephalic vein (SA only). Treated muscle had a progressive decrease in NSAID concentration with increasing depth (SA and MeSA), but it was significantly higher than the concentration in untreated muscle. Substantial amounts of SA and MeSA were also measured in synovial fluid of treated joints. CONCLUSIONS AND CLINICAL RELEVANCE: Topically applied NSAIDs can penetrate deeply into tissues and synovial fluid. Local concentrations higher than circulating systemic concentrations are suggestive that direct diffusion and local blood redistribution are contributing to this effect. Systemic blood concentrations may be inadequate to describe regional kinetics of topically applied drugs.