Root volume as a grading criterion to improve field performance of Douglas-fir seedlings

Three seed sources of 2+0 Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] seedlings were graded into three root-volume categories (<9, 9–13, and >13 cm³) and outplanted to determine (i) differences in survival and growth after one and two growing seasons in the field, (ii) relationship(s) of seedling height after one and two seasons to preplanting nursery root volume, total fresh weight, root-collar diameter, and height, and (iii) differences in field performance due to fertilization at planting. Field survival was >90% among all root-volume categories. Seedlings in the largest category grew significantly better than those in the smaller two categories over two seasons. Apparently, a population of seedlings having a large proportion of high root volumes will outperform a population having a large proportion of low root volumes in the field. Fertilization at the time of planting had no effect on survival or growth because of shallow placement of the fertilizer pellet. The results suggest that targeting root volume, as well as height and diameter, is worthwhile where morphological quality must be maximized to improve field performance. Thus, root volume has potential for use as a criterion for grading seedlings.     

Differences in root longevity of some tree species

Although the importance of root production and mortality to nutrient fluxes in ecosystems is widely recognized, the difficulties associated with root measurements have limited the availability of reliable data. We have used minirhizotrons and image analysis to measure root longevity of Prunus avium L., Picea sitchensis (Bong.) Carrière, Acer pseudoplatanus L. and Populus x canadensis cv. Beaupre directly in cohorts of roots. Major differences in the longevity of roots among species were identified. For example, 40% of Prunus avium roots but only 6% of Picea sitchensis roots survived for more than 14 days. Survival analysis of cohorts of roots of Prunus avium and Populus x canadensis revealed differences in the distribution of longevity among cohorts. Genetic, biotic and abiotic factors that may influence longevity are discussed.     

The effect of a topical anaesthetic formulation, systemic flunixin and carprofen, singly or in combination, on cortisol and behavioural responses of Merino lambs to mulesing

OBJECTIVE: To determine the pain responses of lambs to mulesing, and the effectiveness of potential analgesic treatments. PROCEDURES: Merino lambs (n=64) were allocated at 5 weeks of age to eight treatment groups: 1) sham mules; 2) conventional mules; 3) topical anaesthetic, incorporating lignocaine, bupivicaine, adrenaline and cetrimide, applied immediately after mulesing; 4) flunixin + topical anaesthetic, with flunixin administered 2.5 mg/kg s.c. 90 min before mulesing; 5) carprofen + topical anaesthetic, with carprofen administered 4 mg/kg s.c. 90 min before mulesing; 6) carprofen, administered as above; 7) flunixin, administered as above; and 8) carprofen + flunixin, administered as above. Plasma cortisol was measured at 0, 0.5, 6, 12 and 24 h relative to mulesing. Animal behaviour, including posture, was recorded for 12 h after mulesing. RESULTS: The conventional mules lambs exhibited large increases in plasma cortisol, reduced lying and increased standing with a hunched back compared with sham mules animals. Topical anaesthetic reduced the cortisol peak to mulesing and hunched standing, and increased lying compared with the conventional mules treatment, but generally did not result in values equivalent to sham mules animals. Carprofen, flunixin, and carprofen + flunixin treatments did not reduce the cortisol response to mulesing but substantially ameliorated some changes in behavioural postures. Flunixin + topical anaesthetic reduced the cortisol peak following mulesing and substantially ameliorated most changes in behavioural postures. Carprofen + topical anaesthetic abolished the cortisol peak following mulesing and substantially ameliorated most changes in behavioural postures. All mulesed animals lost weight in the week after mulesing regardless of analgesic administration, but there were no significant differences in growth rate between any of the eight treatments over the 3 weeks after mulesing. CONCLUSIONS: Analgesics can moderate the pain response of lambs to mulesing. The welfare outcome for lambs of mulesing could be improved by use of a combination of local anaesthetic and long acting non-steroidal anti-inflammatory drug.     

Low-temperature synthesis of zintl compounds with a single-source molecular precursor

Thermolysis of the heterobimetallic phosphinidene complex [Sb(PCy)3]2- Li6.6HNMe2 (Cy = C6H11) at 303 to 313 kelvin gives Zintl compounds containing (Sb7)3- anions. The complex thus constitutes a stable molecular single-source precursor to Zintl compounds and provides a potential low-temperature route to photoactive alkali metal antimonates. The new chemical reaction involved, which is driven thermodynamically by the formation of P-P bonds, has implications in the low-temperature synthesis of other technologically important materials (such as gallium arsenide).     

Effects of the repartitioning agent ractopamine on the growth and body composition of rainbow trout, Oncorhynchus mykiss (Walbaum), fed three levels of dietary protein

Ractopamine is a synthetic catecholamine analogue which is known to affect the growth performance of both terrestrial and aquatic livestock species when it is incorporated into their feed. To investigate the effect of ractopamine on fish, rainbow trout, Oncorhynchus mykiss (Walbaum), (initial weight = 385.2 ± 1.4 g) were fed six iso-energetic (16.6 MJ kg^?1) practical diets supplying two levels of ractopamine (0 and 10mgkg^?1) at three levels of crude protein (CP; 25%, 35% and 45%) for 112 days. The mean weight gain (MWT), specific growth rate (SGR), condition factor (CF), viscerosomatic index (VSI), hepatosomatic index (HSI), muscle pigmentation intensity, and the proximate composition of eviscerated carcasses and viscera were measured at 28-day intervals up to day 112. There were no significant (P > 0.05) main effects of ractopamine on any of the responses measured. Significant (P & < 0.05) main effects of dietary protein were observed for MWT, SGR, CF, HSI, pigmentation, eviscerated-carcass ash, and visceral lipid and visceral ash content. Modest but significant (P < 0.05) interactions between ractopamine and protein were observed for HSI, pigmentation intensity and eviscerated carcass moisture content. The protein and lipid contents of both whole viscera and eviscerated carcasses were not affected (P > 0.05) by the inclusion of 10mgkg^?1 ractopamine in the diet. These results indicate that ractopamine may not invoke the beneficial effects of enhancing protein accretion or reducing lipid content of rainbow trout when fed at 10mgkg^?1 of diet at the protein levels tested.     

Determination of glucosinolates using their alkaline degradation and reaction with ferricyanide.

Glucosinolates, a group of naturally occurring thioglucosides, are significant factors impairing the nutritional quality of rapeseed and postextraction rapeseed meal, restricting its use as high-quality protein animal feed. Currently, the European Community standards and Canola definition are being brought in line recommending cultivation and marketing of rapeseed with a glucosinolate content below 18 micromol of total glucosinolates per gram of seeds. Furthermore, some glucosinolates are of increasing interest in Brassica vegetables due to their proven cancer-preventing activities. A novel approach to the analysis of total glucosinolates is reported in this paper based on their alkaline degradation and subsequent reaction of released 1-thioglucose with ferricyanide. The reaction was followed spectrophotometrically using sinigrin and glucotropeaolin as model glucosinolates. The applicability of the method was demonstrated using rapeseed extracts after reducing the interfering effect of phenolics by their adsorption onto polyvinylpolypyrrolidone. Good agreement with official ISO methods was shown.     

Expanded geographical distribution of Myxobolus cerebralis: first detections from Alaska

The parasite responsible for salmonid whirling disease, Myxobolus cerebralis, was introduced to the USA in 1958. It has since spread across the country causing severe declines in wild trout populations, but has never been documented from Alaska. However, while assessing the risk of introduction of M. cerebralis into the state, we detected the parasite using a species-specific polymerase chain reaction (PCR) assay. Testing of 180 hatchery rainbow trout, Oncorhynchus mykiss (Walbaum), by pepsin trypsin digest (PTD) and quantitative PCR (QPCR) revealed 14 positive samples. Infection was confirmed by sequencing the parasite 18S rRNA gene and by a nested PCR assay based on the same gene. Sequence comparison of M. cerebralis from several locations demonstrated the Alaska isolates were genetically distinct and therefore not false-positives arising from contamination during processing. We were unable to visually identify myxospores, indicating that either infection was light or mature spores had not formed. A reference set of fish samples spiked with known numbers of myxospores verified the QPCR and PTD results. This paper presents DNA sequence data from the Alaska M. cerebralis isolates, provides a brief history of the fish and facility of origin, and discusses implications of different testing methods on asymptomatic fish populations.     

Effects of body condition score at parturition and postpartum supplemental fat on adipose tissue lipogenic activity of lactating beef cows

Three-year-old Angus x Gelbvieh beef cows nutritionally managed to achieve a BCS of 4 +/- 0.07 (479.3 +/- 36.3 kg of initial BW) or 6 +/- 0.07 (579.6 +/- 53.1 kg of initial BW) at parturition were used in a 2-yr experiment (n = 36/yr) to determine the effects of BCS at parturition and postpartum lipid supplementation on cow adipose tissue lipogenesis. Beginning 3 d postpartum, cows within each BCS were randomly assigned to be fed hay and a low-fat control supplement or supplements with either cracked high-linoleate safflower seeds or cracked high-oleate safflower seeds until d 60 of lactation. Diets were formulated to be isonitrogenous and isocaloric, and safflower seed diets provided 5% DMI as fat. Adipose tissue biopsies were collected near the tail-head region of cows on d 30 and 60 of lactation. Dietary treatment did not affect (P > or = 0.43) adipose tissue lipogenesis. Body condition score at parturition did not affect acetate incorporation into lipid (P = 0.53) or activity of acetyl CoA carboxylase (P = 0.77) or fatty acid synthase (P = 0.18). Lipoprotein lipase activity and palmitate incorporation into triacyl-glycerol tended to be greater (P = 0.06), and palmitate esterification into total acylglycerols was greater (P = 0.01) in cows with a BCS of 4 at parturition. Mean activity of acetyl-CoA carboxylase (P < 0.001), lipoprotein lipase (P = 0.01), and rate of palmitate incorporation into monoacylglycerol (P = 0.02), diacylglycerol (P = 0.001), triacylglycerol (P = 0.003), and total acylglycerols (P = 0.002) were greater at d 30 than d 60, suggesting a greater proclivity for fatty acid biosynthesis and esterification by adipose tissue at d 30 of lactation. Although dietary lipid supplementation did not affect adipose tissue lipogenesis, results suggest that cows with a BCS of 4 at parturition have a greater propensity to deliver exogenously derived fatty acids to the adipocyte surface and incorporate preformed fatty acids into acylglycerols as stored adipocyte lipid. Additionally, cows in early lactation seemed to be able to synthesize and incorporate more fatty acids into stored lipid than cows during peak lactation.