EFFECTS OF NITROGEN FERTILIZATION OF MIXED SWARDS ON HERBAGE YIELD, DRY MATTER DIGESTIBILITY AND VOLUNTARY FOOD INTAKE OF THE CONSERVED HERBAGES

In 2 experiments nitrogenous fertilizer was applied at 3 levels (0, 46 and 92 lb N/ac) to a permanent pasture and a ryegrass/clover ley and the swards were harvested before ear emergence and conserved as either artificially dried grass or tetrapod hay. Apparent dry matter digestibility and voluntary food intake of the conserved herbages were measured with sheep.
N caused a small but significant depression in apparent DM digestibility but did not affect voluntary food intake. It increased yields of DM and digestible DM significantly.
The DM digestibility and voluntary food intake of hay were always significantly lower than those of the corresponding dried grass. Voluntary food intake of all fodders was directly related to herbage digestibility and inversely related to herbage crude fibre content.     

Screening wheat and sorghum cultivars for aluminum sensitivity at low aluminum levels

Screening cultivars for aluminum (Al) tolerance is often conducted in acid soils or in complete nutrient solutions. The former method lacks precise measurements of Al, and the second requires high Al concentrations because of precipitation and chelation of the Al and is less representative of the actual environmental stresses to which plants must adapt. These experiments were designed to determine Al tolerance of wheat (Triticum aestivum L. em Thell) and sorghum (Sorghum bicolor L. Moench) using incomplete solutions with very low Al concentrations. Six wheat and five sorghum cultivars were screened for Al tolerance in solution culture with 0 to 10 μM Al and only Ca, K, Mg, NO₃, and Cl in the solutions. Plants were subjected to the solutions for 4 d, and the change in relative root length was measured. Solution Al levels and pH were measured after the termination of the experiments. ‘Atlas’ 66 and ‘Stacy’ were the most tolerant wheat cultivars ('Atlas 66’ = ‘Stacy’ ≥ ‘Monon’ ≥ ‘Scout 66’ ≥ ‘Arthur 71’ = ‘Oasis'). The wheat cultivars were effectively separated on a genetic response basis at 2 μM Al. Sorghum cultivars were uniform in their Al tolerance, but did show some separation at 1 μM Al (SC56 > Tx430 > ‘Funk GS22DR’ > SC283 = SC599). The pH and Al variations did not account for any of the differences observed, indicating that root length differences were caused by genetic control of response to high Al.     

Comparative investigation on the susceptibility of faba bean (Vicia faba L.) and sunflower (Helianthus annuus L.) to iron chlorosis

Comparative physiological studies on iron (Fe) chlorosis of Vicia faba L. and Helianthus annuus L. were carried out. High internal Fe contents in Vicia cotyledons (16–37 μg) were completely used for plant growth and Fe chlorosis was not inducible by the application of nitrate (with or without bicarbonate). In Helianthus, low quantities of Fe in the seeds (4 μg) were insufficient for normal growth and without Fe in the nutrient solution, Fe chlorosis was obtained in all treatments. This chlorosis was an absolute Fe deficiency. Also, the treatment with 1 μM Fe in the nutrient solution and nitrate (with or without bicarbonate) led to severe chlorotic symptoms associated with low leaf Fe concentrations and high Fe concentrations in the roots. In contrast, Helianthus grown with NH₄NO₃ and 1 μM Fe had green leaves and high leaf Fe concentrations. However, with NO₃ supply (with or without bicarbonate), Fe translocation from the roots to the upper plant parts was restricted and leaves were chlorotic. Chlorotic and green sunflower leaves may have the same Fe concentrations, leaf Fe concentration being dependent on Fe translocation into the leaf at the various pH levels in the nutrient solution. At low external pH levels (controlled conditions) more Fe was translocated into the leaf leading to similar leaf Fe concentrations with higher chlorophyll concentrations (NH₄NO₃) and with lower chlorophyll concentrations (NO₃). This indicates a lower utilization of leaf Fe of NO₃ grown sunflower plants. Utilization of Fe in faba bean leaves is presumably higher than in sunflower leaves. In Vicia xylem sap pH was not affected by nitrate. In contrast, the xylem sap pH in Helianthus was permanently increased by about 0.4 pH units when fed with nitrate (with or without bicarbonate) compared with NH₄NO₃ nutrition. The xylem sap pH is indicative of leaf apoplast pH. From our earlier work (Mengel et al., 1994; Kosegarten und Englisch, 1994) we therefore suppose that in Helianthus, Fe immobilization occurs in the leaf apoplast due to high pH levels when grown with nitrate (with or without bicarbonate).     

Evaluation of intraperitoneal and incisional lidocaine or bupivacaine for analgesia following ovariohysterectomy in the dog

Objective To determine if intraperitoneal (IP) and incisional (SC) lidocaine or bupivacaine provide analgesia following ovariohysterectomy (OHE). Study Design Prospective, randomized, controlled, blinded clinical trial. Animals Thirty dogs presenting to the Veterinary Teaching Hospital for elective OHE. Methods Dogs were pre‐medicated with acepromazine and butorphanol, induced with thiopental and maintained with isoflurane. They were randomly assigned to three groups: 10 received 8.8 mg kg^?1 2% lidocaine with epinephrine IP (LID); 10 received 4.4 mg kg^?1 0.75% bupivacaine IP (BUP); and 10 received 0.9% saline IP (SAL) upon completion of OHE. All IP doses were standardized to 0.88 mL kg^?1 with saline. An additional 2 mL of undiluted solution was placed SC prior to incisional closure. Dogs were scored at 0.5, 1, 2, 3, 6, 8 and 18 hours post‐extubation by one observer. Dogs were evaluated using a visual analogue scale (VAS) for pain and sedation, and a composite pain scale (CPS) that included physiologic and behavioral variables. Dogs were treated with 0.22 mg kg^?1 butorphanol + acepromazine if their VAS (pain) score was >50. Parametric variables were analyzed using Student's t‐test or repeated measures anova as appropriate. Non‐parametric variables were analyzed by χ²‐test. Results There were no significant differences in age, weight, incision length, surgery time, anesthesia time, or total thiopental dose among groups. Peak post‐surgical pain scores for all groups occurred at 0.5 hours and returned to baseline by 18 hours. Dogs in the BUP group had significantly lower VAS‐pain scores overall than dogs in the SAL group. Seven out of 10 dogs in the SAL group, 4/10 in the LID group and 2/10 in the BUP group were treated with supplemental acepromazine and butorphanol. No differences between groups were detected with the CPS. No adverse side‐effects were observed. Conclusions and clinical relevance Our findings support the use of IP and SC bupivacaine for post‐operative analgesia following OHE in the dog.     

Keratitis in red deer

Twenty-five of 40 red deer (Cervus elaphus) exhibited corneal opacities and ulceration resembling mild bovine infectious keratitis. Attempts to incriminate either a bacterial or viral causal agent were unsuccessful.

Subconjunctival injections of a penicillin/streptomycin mixture were administered in both eyes of affected and in-contact animals. Resolution over an 8 week period was uneventful.     

Colonization of a marker and field strain of Salmonella enteritidis and a marker strain of Salmonella typhimurium in vancomycin-pretreated and nonpretreated laying hens

This study was conducted to evaluate the influence of a vancomycin pretreatment on the ability of marker (nalidixic-acid resistant) Salmonella Enteritidis (SE(M)), field Salmonella Enteritidis (SE(E)), and marker Salmonella Typhimurium (ST(M)) strains to colonize within the intestinal and reproductive tracts and translocate to other organs of leghorn laying hens. In each of three trials, caged laying hens (76, 26, and 33 wk ofage) were divided into six groups designated to receive SE(M), SE(F), or ST(M), and half were pretreated with vancomycin (n = 11-12 hens). Vancomycin-treated hens received 10 mg vancomycin in saline/kilogram body weight orally for 5 days to inhibit Gram-positive bacteria within the intestines. On Day 6, all hens were concurrently challenged by oral, intravaginal, and intracolonal routes with Salmonella and placed into separate floor chambers by Salmonella strain. Two weeks postinoculation, all hens were euthanatized and the ceca, spleen, liver/gall bladder (LGB), upper (URT), and lower (LRT) reproductive tracts, and ovarian follicles were aseptically collected, and analyzed for Salmonella. Results did not differ for the three hen's ages and were therefore combined. The vancomycin pretreatment also had no significant effect on the colonization ability of SE(M), SE(F) or ST(M), and therefore results were combined within Salmonella strain. The marker strain of Salmonella Enteritidis was recovered from 21% of ceca, 4% of LGB, 9% of LRT, and 17% of the fecal samples. The field strain of Salmonella Enteritidis was recovered from 88% of ceca, 96% of spleen, 92% of LGB, 30% of LRT, 4% of URT, 13% of follicle, and 42% of the fecal samples. The marker strain of Salmonella Typhimurium was recovered from 100% of ceca, 74% of spleen, 91% of LGB, 30% of LRT, 9% of URT, 9% of follicle, and 100% of the fecal samples. Among ceca, spleen, LGB, and fecal samples, SE(F) and ST(M) colonization was significantly greater than SE(M) colonization. Overall prevalence of Salmonella in the reproductive tracts of challenged hens was relatively low, ranging from 4% to 30%.     

Evaluation of Equine Albumin Solution in Fluid Therapy in Horses with Colic

Equine albumin solution can be a good therapeutic option in fluid replacement for treatment of horses with colic. The purpose of this study was to evaluate the effects of initial fluid therapy with equine albumin solution in horses presenting with colic and mild-to-moderate dehydration, and to compare this therapy with fluid therapy based on crystalloids alone. Nineteen horses of both genders presenting with colic and mild-to-moderate dehydration were used. Animals were randomly assigned to one of two groups (control: fluid therapy based on crystalloid solutions; experimental: fluid therapy based on equine albumin and crystalloid solutions). Physical examination, hematocrit determination, blood gas analysis, serum biochemistry, blood and peritoneal lactate assessment, and measurement of colloid osmotic and arterial pressure were performed at predetermined times. Good results were obtained with equine albumin solution. More fluid is attracted into and maintained in the intravascular compartment, despite infusion of small volumes, as indicated by higher arterial pressure, lower capillary refill time, lower hematocrit and serum protein concentrations, lower colloid osmotic pressure, and better skin turgor. Equine albumin solution has good oncotic action and is a safe fluid therapy option for horses with colic and mild-to-moderate dehydration. Our results suggest it can be a good choice of fluid for correction of severe dehydration, although further research is necessary to determine the adequate dose in such cases.