Response of Ross 308 and Hubbard broiler chickens to feed removal for different durations during the day

The effects of feed removal for 6, 8, or 10 h during the day from 8 to 28 days of age followed by ad libitum feeding to market age on the growth performance of two strains of broiler chickens, Ross 308 and Hubbard, were studied over 7 weeks. Ross 308 was superior to Hubbard in weight gain and final body weight but consumed more feed and deposited more abdominal fat. Overall, daily feed removal reduced feed intake and improved feed efficiency in all feed-restricted birds, and the longer the period of feed removal the better the efficiency of utilization, but it had no significant effect on weight gain and market weight. It is suggested that for broiler production in the tropics, Ross 308 could be used on a 10-h daily feed removal program from 8 to 28 days of age.     

Canine parvovirus in Australia: The role of socio-economic factors in disease clusters

To identify clusters of canine parvoviral related disease occurring in Australia during 2010 and investigate the role of socio-economic factors contributing to these clusters, reported cases of canine parvovirus were extracted from an on-line disease surveillance system. Reported residential postcode was used to locate cases, and clusters were identified using a scan statistic. Cases included in clusters were compared to those not included in such clusters with respect to human socioeconomic factors (postcode area relative socioeconomic disadvantage, economic resources, education and occupation) and dog factors (neuter status, breed, age, gender, vaccination status). During 2010, there were 1187 cases of canine parvovirus reported. Nineteen significant (P<0.05) disease clusters were identified, most commonly located in New South Wales. Eleven (58%) clusters occurred between April and July, and the average cluster length was 5.7days. All clusters occurred in postcodes with a significantly (P<0.05) greater level of relative socioeconomic disadvantage and a lower rank in education and occupation, and it was noted that clustered cases were less likely to have been neutered (P=0.004). No significant difference (P>0.05) was found between cases reported from cluster postcodes and those not within clusters for dog age, gender, breed or vaccination status (although the latter needs to be interpreted with caution, since vaccination was absent in most of the cases). Further research is required to investigate the apparent association between indicators of poor socioeconomic status and clusters of reported canine parvovirus diseases; however these initial findings may be useful for developing geographically- and temporally-targeted prevention and disease control programs.     

Prognostic factors for tumor remission and survival in dogs after surgery for primary lung tumor: 76 cases (1975-1985)

The association of various prognostic factors with remission and survival after the excision of lung tumors was evaluated in 76 dogs. Overall, the median survival time of treated dogs was 120 days; 72% had tumor that underwent remission (median duration of remission, 120 days). Dogs with tumors that underwent remission had significantly (P = 0.001) increased survival time (median, 330 days vs 28 days for dogs with tumors that did not undergo remission). The finding of normal-sized lymph nodes at the time of therapeutic thoracotomy was significantly (P = 0.001) correlated with increased remission probability (85.4% remission rate vs 43.6% in dogs with large lymph nodes). Use of various diagnostic methods to find normal regional lymph nodes before surgery indicated that such finding was significantly (P less than or equal to 0.01) correlated with increased remission duration (median remission duration, 365 days, vs 60 days for tumors in dogs with large lymph nodes), and the finding of normal lymph nodes at the time of surgery was significantly (P less than or equal to 0.01) correlated with increased survival time (median, 345 days, vs 60 days for dogs with large lymph nodes).     

A study of "white spotted kidneys" in cattle

A study was performed at an abattoir in Australia, in an attempt to correlate focal chronic interstitial nephritis (FCIN) producing the so-called "white spotted kidney", with Leptospira spp. and other pathogens in cattle. Samples of kidneys, urine and blood were collected immediately after slaughter from 46 two-year-old heifers, and 72 cows and bulls with gross lesions consistent with FCIN. The same samples were also collected from nine heifers and 12 cows with no gross kidney lesions. Aqueous humour was also collected from the eye of 17 of the adult animals. The sera were processed by a microscopic agglutination test for leptospira antibodies, while all the other samples were cultured for Leptospira spp. and also processed for routine aerobic and anaerobic culture for other pathogens. Sub-samples from all the kidneys were fixed in 10% buffered formalin and processed histologically. Antibody titers of 1:400 or higher for Lepstospira borgpeterseni serovar hardjo were found in six adult animals with FCIN and in one adult animal with no gross kidney changes, while antibody titers of 1:400 to L. borgpeterseni serovar tarassovi were found in only one animal with FCIN. L. borgpeterseni serovar hardjo was isolated from the urine and kidney of one adult animal and from the urine of another adult animal, both with FCIN. No pathogens were isolated from any of the other samples. The histological lesions were consistent in most cases with FCIN. The results suggest that neither Leptospira spp. nor active infection by other bacteria are associated with the so-called "white spotted kidneys".     

Effects of Melatonin Implants During Non‐Breeding Season on Sperm Motility and Reproductive Parameters in Rasa Aragonesa Rams

The effect of melatonin implants administered during non‐breeding season in Rasa Aragonesa rams on sperm motility parameters and other reproductive traits was assessed. In a first experiment, two Rasa Aragonesa rams were implanted (with melatonin group M), remaining other two males as control group (C). Semen of each group was collected from 1 May to 23 June, twice or three times a week, and motility parameters were assessed using a computer‐assisted sperm analysis system. Melatonin increased the percentage of progressive motile spermatozoa, particularly during 46–75 days after melatonin implantation (p < 0.01). In experiment 2, M and C in vitro fertilization ability had been determined by zona‐pellucida binding assays, using spermatozoa from experiment 1, obtained 60–70 days after melatonin was implanted. A significantly higher number of spermatozoa attached per oocyte was observed in frozen‐thawed immature ovine oocytes incubated with sperm from M animals than in those incubated with sperm from the C group (p < 0.01). Finally, a field assay (experiment 3) was performed. In this case, five Rasa Aragonesa rams were implanted with melatonin and three remained as control group. Sperm doses from those animals were used for artificial insemination of 2608 Rasa Aragonesa ewes from 39 different farms at non‐breeding season. Fertility, litter size and fecundity were studied. Semen from melatonin implanted rams seemed to increase both fertility and fecundity in ewes inseminated with spermatozoa obtained 46–60 days after implantation (p < 0.1). Thus, melatonin treatment in rams during non‐breeding season modifies sperm motility parameters and seems to improve the fertilization parameters obtained.