Effects of crop management practices on Echinochloa crus-galli and Chenopodium album seed production in a maize/soyabean rotation

Seed production of residual weed populations needs to be taken into account when estimating the long-term impact of low-input agronomic practices. The objective of this study was to measure the effects and interactions of crop, weed control, tillage practice and nutrient source on the seed production of the dominant residual weed species in a maize/soyabean rotation at two sites: Echinochloa crus-galli (L.) Beauv. on a Sainte-Rosalie clay and Chenopodium album L. on a Duravin clay loam. Seed production per unit area was estimated in each experimental unit. Weed seed production was greater under mechanical weed control compared with chemical weed control. In 1997, E. crus-galli seed production reached over 326 000 seeds m^–2 in mechanical weed control treatments, but averaged less than 500 seeds m^–2 in the chemical weed control treatments. Chenopodium album produced in the range of 766 000 and 73 000 seeds m^–2 in mechanical and chemical weed control treatments respectively. Very few or no weed seeds were produced in soyabean under chemical control. Tillage intensity and nutrient source did not affect seed production of either weed species, with the exception that E. crus-galli produced more seeds in chisel than in mouldboard plough tillage in soyabean. Weed control method had more impact on seed production than tillage intensity and nutrient source in a maize/soyabean rotation.     

Serum Levels of Cardiac Markers NT‐proANP and NT‐proBNP in Brachycephalic bitches at Different Gestational Stages

The aim of this study was to determine serum levels of natriuretic peptide precursors (NT‐proANP and NT‐proBNP) during pregnancy in brachycephalic bitches. Fifteen healthy multiparous bitches were selected for this prospective study. Serum levels of NT‐proANP and NT‐proBNP were measured during anoestrous and at 14, 35, 42, 49 and 56 days (2nd, 5th, 6th, 7th and 8th weeks) of pregnancy. Fourteen animals had normal gestations, and one bitch developed single foetus syndrome. The natriuretic peptide levels of this animal were not included in this study; however, it is important to report that its NT‐proANP levels were four times greater than those of normal patients. There was no significant difference (p = 0.072) in NT‐proBNP levels between anoestrous (0.20 ± 0.10 ng/ml) and the different pregnancy weeks (0.27 ± 0.12 ng/ml). There was a positive correlation (p < 0.0001) between NT‐proANP and gestational age, and the levels of this marker increased significantly (p < 0.0001) during the 6th (0.26 ± 0.06 ng/ml), 7th (0.28 ± 0.04 ng/ml) and 8th weeks (0.29 ± 0.05 ng/ml) when compared to anoestrous (0.18 ± 0.02 ng/ml). NT‐proANP serum levels are correlated with gestational development and may be indicative of cardiovascular adaptation in canine brachycephalic pregnancy.     

Complications associated with cannula insertion techniques used for laparoscopy in standing horses

OBJECTIVE: To report our experience and complications associated with different cannula insertion techniques for laparoscopy in standing horses. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Forty horses that had laparoscopy for diagnostic or surgical purposes. METHODS: After a physical examination, including rectal palpation, standing laparoscopy was performed in 40 sedated horses. Local anesthetic was injected at each site of cannula insertion in the left flank. Horses were divided into 5 groups: Pneumoperitoneum was induced before cannula insertion using a Verres needle (group 1, n = 3) or a 12-g catheter (group 2, n = 14); the cannula was inserted before inducing a pneumoperitoneum (group 3, n = 9); the cannula was inserted under visual control, using an operating laparoscope (group 4, n = 2) or a Visiport Optical Trocar (group 5, n = 12). Horses were observed for 7 days. RESULTS: Problems with insufflation or cannula insertion occurred in 12 horses: 6 had peritoneal detachment, 4 had a splenic puncture, and 2 had descending colon puncture. Eleven of these complications occurred in groups 1 to 3 and only 1 in groups 4 and 5. CONCLUSIONS: The Visiport optical device allows controlled insertion of the initial trocar, and thus avoided potential problems associated with "blind" cannula insertion techniques and was used effectively in horses that had feed withheld for 12 hours. This technique enables direct insertion of a cannula directly into the right flank. CLINICAL RELEVANCE: Complications associated with initial cannula insertion in the paralumbar fossa, for laparoscopy, in standing horses can be minimized with the use of an optical cannula.     

Assessment of a bone biopsy technique for measuring tiludronate in horses: a preliminary study

This study assessed the feasibility of measuring tiludronate in horses using a minimally invasive bone biopsy technique. Eight horses were treated with intravenous (IV) tiludronate [1 mg/kg bodyweight (BW)], either once (n = 4) or twice, 28 d apart (n = 4). The horses that were treated once were euthanized on days 1, 43, 57, or 92 and those that were treated twice, were euthanized on days 112, 154, 194, or 364. Bone samples were taken bilaterally from each horse at 4 sites: the third metacarpal bone (MCIII), the 13th rib (R13), the tuber coxae (TC), and the cuboid bone (CB). Test samples were taken with a 5-mm diameter dental drill, while larger reference samples were taken with an osteotome. The concentrations of tiludronate were measured by high performance liquid chromatography (HPLC) with ultraviolet (UV) detection. The TC was the easiest site to sample, and no technical difficulties were encountered for extraction and measurement. Drill sampling at the MCIII was difficult. Moreover, both the extraction and measurement caused technical problems and results were unreliable in most cases (93%). Drill samples obtained from the R13 were very small and access to the CB required considerable dissection, which would not be feasible in vivo. Forty-six percent and 36% of the tiludronate measurements performed on the R13 and CB samples, respectively, were unreliable. The ratio of tiludronate concentrations ranged from 73% to 185% (median: 118%) in the TC, 65% to 208% (median: 81%) in the R13, and 26% to 110% (median: 57%) in the CB. In all but 1 horse, the highest concentrations of tiludronate were found in the TC. It was concluded that bone biopsies performed at the TC were adequate for measuring tiludronate in horses and should be considered in future for repeated measurements over time in living animals.     

Anti‐Mullerian Hormone Concentration and Antral Ovarian Follicle Population in Murrah Heifers Compared to Holstein and Gyr Kept Under the Same Management

This study was performed to evaluate plasma concentrations of anti‐Mullerian hormone (AMH) and the ovarian antral follicle population (AFP) in different genetic groups. Cyclic heifers (13 Bubalus bubalis [Murrah]; 15 Bos taurus [Holstein] and 10 Bos indicus [Gyr]) were maintained under the same management and were synchronized with two doses of 150 μg IM d‐cloprostenol administered 14 days apart. After the second d‐cloprostenol treatment, heifers had their ovaries scanned daily by ultrasound to define the day of ovulation. On the same day, the AFP was determined and a plasma sample was collected to measure AMH. Murrah heifers had less AFP (25.6 ± 2.1 follicles; p = 0.01) and plasma AMH concentration (0.18 ± 0.03 ng/ml; p < 0.001) than Gyr (60.0 ± 12.2 follicles and 0.60 ± 0.12 ng/ml of AMH); however, data were similar when compared to Holstein (35.9 ± 6.8 follicles and 0.24 ± 0.06 ng/ml of AMH) heifers. Regardless of genetic background, there was a positive relationship between the AFP and plasmatic AMH concentration (Murrah [r = 0.62; p < 0.01], Holstein [r = 0.66; p < 0.001] and Gyr [r = 0.88; p < 0.001]). Also, when heifers were classified according to high‐ or low‐AMH concentration based on the average within each genetic group, high‐AMH heifers had greater (p < 0.0001) AFP than low‐AMH heifers. In conclusion, both Murrah and Holstein heifers presented lower plasma AMH concentration and AFP when compared to Gyr.     

Improving the Reproductive Efficiency, Pregnancy Diagnosis and Monitoring the Resumption of Luteal Activity in Indigenous Damascus Goats

Seventy‐five female Damascus goats aged between 1.5 and 5.5 years were used to evaluate the effectiveness of the intravaginal sponges and prostaglandin analogue on oestrous synchronization and fecundity; to diagnose pregnancy and to monitor the resumption of the luteal activity. Females were divided randomly, during the breeding season, into three equal groups, S, P and C. Females in group S were fitted with sponges containing 45 mg of flugestone acetate (FGA) for 14 days and injected with pregnant mare serum gonadotrophin (PMSG) at the sponge withdrawal. Females in group P were given two injections of prostaglandin F2α analogue at 11‐day intervals, whereas females in group C (control) received no treatment. The results showed that there was a significant difference (p < 0.001) in oestrous exhibition between females in group S as compared with those in groups P and C, with means being 30 ± 10, 172 ± 115 and 217 ± 75 h for groups S, P and C, respectively. Kidding rates resulting from the first and all matings were 80 and 88, 52 and 88, and 68 and 80% for groups S, P and C, respectively. Fecundity rates were 215, 175 and 180% for groups S, P and C, respectively, with a significant difference (p < 0.05) between the S and both P and C groups. Using an ultrasound pregnancy detector performed on days 57 ± 3 after mating, positive pregnancy diagnosis was 93.3% and 100% for non‐pregnancy. Females in the control group showed functional corpus luteum starting in September. It is concluded that FGA sponges plus PMSG treatment could be successfully used to synchronize oestrus and improve fecundity; whereas prostaglandin treatment was not effective to synchronize oestrus. It is also concluded that pregnancy can be diagnosed accurately and successfully using an ultrasound pregnancy detector. In addition, ovarian activity in the Damascus goat in Syria resumes in September.     

Genetic and amino acid analysis of the GL protein of Canadian, American and European equine arteritis virus isolates.

The genetic variation in equine arteritis virus (EAV) GL protein encoding gene was investigated. Nucleic and deduced amino acid sequences from 7 different EAV isolates, including 4 eastern Canadian field isolates, were compared with those of the Bucyrus reference strain. Nucleotide sequence identities between these isolates and the Bucyrus reference strain ranged from 87.5% (Vienna isolate) to 93.9% (11958 isolate). Amino acid identities with the Bucyrus reference strain varied from 90.2% (Vienna isolate) to 95.1% (19933 isolate). A 2nd potential N-linked glycosylation site was found at position 81 in the GL protein of all EAV isolates. Three amino acid substitutions at residue position 90 (Glu-->Val), position 101 (Ala-->Val or Thr), and position 119 (Val-->Leu, Phe or Ser) were also found in all EAV isolates. Phylogenetic analysis showed that the North American EAV isolates, including the Canadian isolates, and the European prototype Vienna isolate could be classified in 2 distinct groups. Three putative sequential antigenic sites were predicted in EAV GL protein. The 1st antigenic site (TAQRFT) was located at positions 24 to 29, and the 2nd antigenic site (RYDEHTA) at positions 47 to 53. The 3rd antigenic site was predicted to be located at positions 78 to 84 and showed the less conserved amino acid sequence.     

Comparison of two techniques for injection of the podotrochlear bursa in horses

OBJECTIVE: To compare accuracy of 2 methods for injection of the podotrochlear bursa in horses. DESIGN: Observational study. ANIMALS: 17 French Standardbreds. PROCEDURE: In each horse, contrast medium was injected into the podotrochlear bursa of 1 foot by use of a distal palmar approach with the needle inserted parallel to the sole (DPPS) and into the podotrochlear bursa of the other foot by use of a distal palmar approach to the navicular position (DPNP). Podotrochlear bursa injection was evaluated by means of radiographic examination in all horses and postmortem examination in 6. RESULTS: Contrast medium was successfully injected into the podotrochlear bursa in 6 of 16 feet in which the DPPS method was used and 14 of 17 feet in which the DPNP method was used; these results were significantly different. Failure was attributed to contrast medium invading the distal interphalangeal joint, contrast medium pooling palmar to the deep digital flexor tendon, contrast medium located in the podotrochlear bursa and the distal interphalangeal joint, contrast medium located in the podotrochlear bursa and the area palmar to the deep digital flexor tendon, and an inability to inject contrast medium despite adequate needle placement. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the DPNP technique can be used successfully for injection into the podotrochlear bursa in horses. However, radiographic assessment should be used to confirm that material was injected into the bursa.