A comparison of the effects of carbon dioxide and medical air for abdominal insufflation on respiratory parameters in xylazine-sedated sheep undergoing laparoscopic artificial insemination

AIMS: To determine if abdominal insufflation with medical air will improve oxygenation and ventilation parameters when compared to insufflation with CO₂ in xylazine-sedated sheep undergoing laparoscopic artificial insemination (AI).

METHODS: Forty-seven sheep underwent oestrus synchronisation and were fasted for 24 hours prior to laparoscopic AI. Each animal was randomised to receive either CO₂ or medical air for abdominal insufflation. An auricular arterial catheter was placed and utilised for serial blood sampling. Respiratory rates (RR) and arterial blood samples were collected at baseline, after xylazine (0.1?mg/kg I/V) sedation, 2 minutes after Trendelenburg positioning, 5 minutes after abdominal insufflation, and 10 minutes after being returned to a standing position. Blood samples were collected in heparinised syringes, stored on ice, and analysed for arterial pH, partial pressure of arterial O₂ (PaO₂), and CO₂ (PaCO₂). The number of ewes conceiving to AI was also determined.

RESULTS: Repeated measures ANOVA demonstrated temporal effects on RR, PaO₂, PaCO₂ and arterial pH during the laparoscopic AI procedure (p<0.001), but no difference between insufflation groups (p>0.01). No sheep experienced hypercapnia (PaCO₂>50?mmHg) or acidaemia (pH<7.35). Hypoxaemia (PaO₂<70?mmHg) was diagnosed during the procedure in 14/22 (64%) ewes in the CO₂ group compared with 8/23 (35%) ewes in the medical air group (p=0.053). Overall, 15/20 (75%) ewes in the CO₂ group conceived to AI compared with 16/22 (72.7%) in the medical air group (p=0.867).

CONCLUSIONS AND CLINICAL RELEVANCE: There were no statistical or clinical differences in RR, PaO₂, PaCO₂, pH, or conception to AI when comparing the effects of CO₂ and medical air as abdominal insufflation gases. None of the sheep experienced hypercapnia or acidaemic, yet 42% (19/45) of sheep developed clinical hypoxaemia, with a higher percentage of ewes in the CO₂ group developing hypoxaemia than in the medical air group. Based on the overall analysis, medical air could be utilised as a comparable alternative for abdominal insufflation during laparoscopic AI procedures.     

Effects of deep tillage and fertilization on soya yields in a compacted Ustochrept during seven cropping seasons, Santa Cruz, Bolivia

A study was carried out in tropical eastern Bolivia to determine the profitability of deep tillage practices and fertilization on soya in a compacted sandy loam Ustochrept. The experimental site is characterized by summer and winter cropping seasons with average rainfalls of 807 and 235 mm respectively.

A field trial was conducted over four summer and three winter cropping seasons (1985–1989) using a randomized complete block design with four tillage treatments and four replicates which was converted into a split-plot design by with- and without-fertilizer subtreatments in the second year. The tillage treatments (and mean tillage depth) were:

1. (1) Conventional — generally two passes of a heavy disc harrow (0.15 m) followed by two passes of a light disc harrow.

2. (2) Disc ploughing in 1985 — one pass of a disc plough (0.30 m) in 1985 only, followed by conventional tillage.

3. (3) Subsoiling in 1985 — two overlapping passes of a subsoiler (0.40 m) to give 0.37 m tine separation distances in 1985 only, followed by conventional tillage.

4. (4) Annual subsoiling — as for subsoiling in 1985 but with subsoiling every year.

For the seven cropping seasons, 1985–1989, the percentage yield increases from subsoiling in 1985, disc ploughing in 1985 and annual subsoiling compared with yields from conventionally tilled (compacted) plots were 14%, 19% and 25% respectively, equivalent to partial gross margins of US$ 230, 306 and 378 ha⁻¹. Significant differences were found between both the disc ploughing in 1985 and annual subsoiling treatments compared with conventional tillage; the residual effects of disc ploughing annual subsoiling in 1985 were observed to last 3 and at least 4 years respectively.

Significant fertilizer responses were obtained in 2 of the 3 years but were not economic owing to high fertilizer costs. No significant tillage×fertilizer interaction effect was found.

Soya responses due to annual subsoiling varied from 0 to 90% and were shown to be significantly and inversely related to seasonal rainfall when the latter was <760 mm, and to be approximately zero at higher seasonal rainfalls, provided that yields were not influenced by population differences. The higher responses of subsoiling at low seasonal rainfalls were attributed to increased rooting depth and hence to increased moisture supply. It was estimated that the minimum soya yield responses expected 7 years in 10 would be 0% in summer and 56% in winter, equivalent to a partial gross margin of US$ 98 ha⁻¹ for the first year.     

Utilization of enzyme mixtures to retard bread crumb firming

The influence of enzyme mixtures containing amylase and lipase activities on straight dough bread staling was studied. Amylopectin retrogradation, crumb firming, amylose-lipid complexes, and dextrin production were analyzed in bread samples supplemented with two enzyme mixtures. The addition of enzyme mixtures to bread formula causes a beneficial effect on bread keeping properties and the formation of a more thermostable amylose-lipid complex than the one found in control bread. Amylopectin retrogradation was inhibited by the use of the enzyme; the effect was accompanied by reduced crumb-firming rates. The enzymatically generated water-soluble dextrins (maltose and DP3, DP4, DP5, and DP6 dextrins) are the most effective in preserving crumb softness during bread storage.     

能否像种蘑菇一样生产商品肉猪

在最近的10年中,现代猪种的生产性能已经得到了显著的提高,并且今后肯定将进一步提高。然而,猪生产性能的提高存在着一定的限度,因为尽管猪的遗传潜力得到了提高,但由于动物营养和保健技术进展缓慢使该潜力极少能够实现。     

Processes affecting the dissipation of the herbicide isoxaflutole and its diketonitrile metabolite in agricultural soils under field conditions

Two-year field dissipation studies were conducted in three soil types in Minnesota to examine the processes affecting the dissipation of the herbicide isoxaflutole and its phytotoxic diketonitrile metabolite (DKN) under relatively cool, wet soil conditions. Plots of cuphea were treated with isoxaflutole and potassium bromide, a nonsorbed, nondegraded tracer. Replicate soil cores were collected six times during the growing season to a depth of 1 m, and the bromide or herbicide concentration was measured in each of five depth increments. The dissipation half-life (DT50) of isoxaflutole + DKN was 8-18 days in each soil. Bromide and herbicide concentrations were low at depths >40 cm throughout the study, and herbicide concentrations in soil 100 days after application were usually undetectable. Simulation modeling using Hydrus-1D for the loam soil suggested that plant uptake was an important mechanism of dissipation.     

Bioavailability of calcium from milk-based formulas and fruit juices containing milk and cereals estimated by in vitro methods (solubility, dialyzability, and uptake and transport by caco-2 cells)

An adequate calcium intake during the first years of life is needed for normal growth and development and to prevent rickets. The bioavailability of calcium from infant foods (milk-based formulas and fruit juices containing milk and cereals, FMC), the dietary sources of calcium in these stages of life, has been estimated on the basis of simulated gastrointestinal digestion and calcium solubility and dialyzability values and on the efficiency of transport and uptake by Caco-2 cells. The ranking of samples according to calcium bioavailability depends on the use of solubility or dialyzability as criterion. On the basis of the former, the highest value corresponded to adapted formulas and the lowest to fruit juices. However, when using percentage dialysis, the highest value corresponded to fruit juices and the lowest to follow-up formulas. The highest percentages of transport efficiency and uptake by Caco-2 cells corresponded to calcium from the analyzed fruit juices, followed by toddler, follow-up, and adapted formulas.