Effects of Stocking Sac-Fry and Hatchery-Fed Fry on Production of Fingerling Channel Catfish Ictalurus punctatus

Abstract.— Channel catfish Ictalurus punctatus fry are typically held under hatchery conditions for 7 to 14 d after hatching to allow feeding and growth before they are stocked into nursery ponds to produce fingerling catfish. In an attempt to reduce hatchery operating costs, several catfish fingerling producers in Louisiana presently stock fry within 2 d after hatching before yolk absorption is complete. Fry at this stage of development are commonly referred to as "sac-fry." Although research has shown that fry can be stocked at the onset of yolk absorption with no detrimental effects on subsequent fingerling production, stocking sac-fry has been reported to result in reduced fingerling survival. To further investigate this topic, production trials were conducted in experimental outdoor pools over the course of two growing seasons to evaluate the effect of stocking fry of three different ages (2-, 7-, and 14-d post-hatch, DPH) on survival, growth (weight and length), condition factor (K), yield, feed consumption, and feed conversion ratio (FCR) of fingerling catfish. Results from both trials indicated that the age at which fry were stocked had no effect on production characteristics with the exception of growth. Specifically, fingerlings reared from fry stocked at 2 and 7 DPH were significantly larger than fingerlings reared from fry stocked at an age of 14 DPH. These findings suggest that the practice of stocking sac-fry may be a suitable alternative to the traditional procedure of holding and feeding fry under hatchery conditions prior to stocking. However, in order to fully evaluate the effects of early-age stocking of catfish fry on fingerling production, additional studies must be conducted under pond conditions. Furthermore, these studies must be coupled with a rigorous economic analysis before the practice of stocking sac-fry can be recommended to the catfish industry.     

Laparoscopic-assisted cystotomy for urolith removal in geldings

OBJECTIVE: To describe a technique for laparoscopic-assisted removal of cystic calculi in geldings and report outcome. STUDY DESIGN: Clinical report. ANIMALS: Four geldings with cystic calculi. METHODS: Laparoscopic-assisted cystotomy and urolith retrieval was performed in 4 anesthetized geldings positioned in dorsal recumbency. With a laparoscope portal located at the umbilicus, the abdomen was insufflated and then the surgical table was tilted (30 degrees head-down position) before an instrumental portal was created parallel and 2-3 cm medial to the left external inguinal ring. Laparoscopic grasping forceps were inserted to grasp the cranial aspect of the bladder and elevate it to the ventral abdominal wall. With the instrumental portal as mid-point, the parainguinal skin incision was longitudinally extended cranial and caudal (approximately 8-10 cm) to accommodate the size of the urolith. The apex of the bladder was exteriorized and sharply incised, the urolith extracted, and after cystotomy closure, the bladder was repositioned. The mini-laparotomy and trocar incisions were closed in layers. RESULTS: There were no intra- or post-operative complications. All horses had minor incisional swelling for 3-4 days. No signs of abdominal or incisional pain were observed. Hematuria and slight stranguria occurred until the 3rd or 4th day. Surgical time (skin incision to skin closure) was 35-40 minutes. On long-term follow-up (up to 12 months) no recurrence of clinical signs associated with cystic calculi occurred. CONCLUSION: Uroliths (6-8 cm diameter) can be removed by laparoscopic-assisted cystotomy in geldings. CLINICAL RELEVANCE: Laparoscopic-assisted cystotomy combines the advantages of the parainguinal laparocystotomy with laparoscopic technique for removal of cystic calculi while avoiding their disadvantages.     

Prevalence of dog erythrocyte antigen 1.1 in dogs in Switzerland evaluated with the gel column technique

Canine blood typing has become an established and essential laboratory test due to the rising demand for safe and efficient blood transfusions. The most immunogenic and clinically important blood type is DEA 1.1. Little is known about DEA 1.1 frequencies or special characteristics among different canine breeds. 304 dogs were tested for DEA 1.1. DEA 1.1-typing was performed using a commercial gel column technique (ID-Gel Test Canine DEA 1.1, DiaMed, Cressier, Switzerland). Fifty-three percent of all tested dogs reacted positive for DEA 1.1, whereas 49 % of the mixed breeds tested DEA 1.1-positive. All Bernese mountain dogs (n = 22) and Rottweilers (n = 9) tested positive for DEA 1.1, while all Boxers (n = 8), Flat-Coated Retrievers (n = 9), and Border Collies (6) tested negative for DEA 1.1. The prevalence of DEA 1.1 in dogs in Switzerland was found to be comparable to that reported from other countries. The tested breeds were found to differ considerably in the frequency of DEA 1.1. This knowledge is useful for selection of blood donors. However, DEA 1.1 blood typing of donor and recipient prior to transfusion and cross matching in sensitized dogs is unavoidable.     

The influence of colostral antibodies on the postvaccinale humorale immune response in neonatal calves

The aim of this study was to evaluate the efficiency of vaccination of young calves and to see whether maternal antibodies may influence the immunological response in calves. For this project 20 matched-pairs of cows and their offspring were selected. Of each pair, one cow received a placebo 8 and 4 weeks before term (group A) and the other was vaccinated against Feline Leucose Virus, FeLV, with Leucogen? (group B). All calves received colostrum from their respective mother shortly after birth and all calves were vaccinated with Leucogen? 10 days after birth. Blood samples from the cows and calves were taken during the whole study period (till four weeks after calf vaccination). An ELISA test was done in the lab to define the FeLV antibody concentration. 30 % of the vaccinated cows showed a seroconversion, 13 out of 20 vaccinated cows passed the antibodies onto their calves. 11 calves of group B did not convert in comparation of only 4 of group A. All seroconverted calves had low antibody concentration before their vaccination. Calves of group B with a low passive antibody level at the beginning showed a higher seroconversion as compared to calves with higher antibody concentrations of the same group. Two thirds of the calves without maternal antibodies reacted adequately to the vaccination. Therefore, an early vaccination of calves can be recommended.     

Comparison of 2 Doses of Recombinant Human Thyrotropin for Thyroid Function Testing in Healthy and Suspected Hypothyroid Dogs

Background: Various protocols using different doses of recombinant human thyrotropin (rhTSH) in TSH stimulation testing have been described. However, the influence of TSH dosage on thyroxine (T4) concentration has not yet been evaluated in suspected hypothyroid dogs.
Objective: To evaluate the effectiveness of 2 doses of rhTSH.
Animals: Fifteen dogs with clinical signs consistent with hypothyroidism and abnormal stimulation results with 75 μg rhTSH and 18 clinically healthy dogs.
Methods: All dogs were stimulated with 75 and 150 μg rhTSH IV in a 1st and 2nd stimulation test, respectively. Blood samples were taken before and 6 hours after rhTSH administration for determination of total T4 concentration.
Results: Using the higher dose led to a normal test interpretation in 9 of the 15 dogs, in which stimulation had been abnormal using the lower dose. Based on follow-up information, hypothyroidism was excluded in 7 of these 9 dogs. In all 6 dogs with a blunted response to the higher dose, hypothyroidism could be confirmed. Healthy dogs showed significantly higher post-TSH T4 concentrations with the higher compared with the lower dose. Post-TSH T4 concentrations after TSH stimulation were not related to dogs' body weight in either healthy or diseased dogs.
Conclusions and Clinical Relevance: TSH dose significantly influenced test interpretation in suspected hypothyroid dogs. Differentiation between primary hypothyroidism and nonthyroidal disease was improved with 150 μg rhTSH. Because this effect was independent of the dogs' body weight, the higher dose is recommended in dogs that have concurrent disease or are receiving medication.