Ruminal pH and its relationship with dry matter intake, growth rate, and feed conversion ratio in commercial Australian feedlot cattle fed for 148 days.

OBJECTIVES: Measurement of ruminal pH throughout a 148-day feeding period in cattle fed commercial diets and to relate this to feed intake, growth rate and feed conversion ratio. Factors contributing to variation in rumen pH, including meal frequency, duration and weight, and, total daily intake, were also evaluated. METHODS: Forty-eight cattle were randomly allocated to two pens and 12 randomly selected from each pen had rumen pH monitoring boli inserted. Ruminal pH was measured every 10 min and feed intake was measured continually. The cattle were fed a commercial feedlot diet for 148 days and weighed into and out of the feedlot to measure growth rate and to calculate feed conversion ratio. Cattle from both pens were registered to collect individual feed intake data using the GrowSafe® feed management system. RESULTS: Mean ruminal pH decreased with days on feed. Mean daily dry matter intake was the major contributor to greater average daily gain and lower ruminal pH. Lower mean ruminal pH was associated with greater average daily gain and lower feed conversion ratio, where it remained above the threshold of 5.6. There was no association between ruminal pH and average daily gain or feed conversion ratio for mean ruminal pH below 5.6. CONCLUSIONS: Ruminal acidosis can occur at any time during the feeding period, and the risk could be greater as days on feed increase. Feedlot production outcomes are not improved by ruminal pH depression below the threshold of 5.6.

Prevalence of clinicopathological changes in healthy middle-aged dogs and cats presenting to veterinary practices for routine procedures.

OBJECTIVE: The objective of the present study was to investigate the frequency of abnormal clinicopathological parameters in a population of client-owned clinically healthy middle-aged dogs and cats. MATERIALS AND METHODS: Biochemical and haematological profiles, urinalysis and total T4 were measured in clinically healthy middle-aged dogs (age, 5-8 years) and cats (age, 6-9 years) presenting to veterinary practices for routine procedures. RESULTS: Of the 406 dogs, only 55 had no abnormalities identified in the testing panel. Most changes were minor or considered artifactual; however, changes that were diagnostic of significant disease or warranting additional evaluation were identified in 25 dogs (6.2%). Of the 130 cats, only 26 had no abnormalities identified in the testing panel. Most changes were minor or considered artifactual; however, changes diagnostic of significant disease or warranting additional evaluation were identified in 25 cats (19.2%). Significant abnormalities included anaemia, inflammation and evidence of liver, kidney and pancreatic disease. CONCLUSION: Biochemical and haematological testing as part of regular preventive health checks may facilitate early detection of diseases before they present clinically, allowing earlier intervention and better health outcomes.

Therapeutic and protective efficacy of doramectin injectable against gastrointestinal nematodes in cattle in New Zealand: a comparison with moxidectin and ivermectin pour-on formulations.

Two similar studies were conducted in New Zealand to compare the therapeutic and persistent activity of doramectin injectable, moxidectin pour-on, ivermectin pour-on and oxfendazole oral drench when administered to nematode-infected cattle which were then grazed on common pastures. On day 0 (treatment day), 40 cattle were weighed, faecal sampled and allocated on the basis of day--3 faecal egg counts (FEC) to four treatment groups. Cattle were then treated with either doramectin by subcutaneous (s.c.) injection, moxidectin and ivermectin by topical application, or oxfendazole orally using label-recommended dosages. Oxfendazole treatment served primarily as a control to monitor reinfection without persistent activity. Faecal samples for nematode egg counts and coprocultures for larval differentiation were collected six times between day 0 and day 56 and all cattle were reweighed on day 56. Doramectin reduced pretreatment FEC by 99.1% in the first study and by 100% in the second study when assessed at 14 days posttreatment. Corresponding reductions for moxidectin were 80.8% and 85.2%, for ivermectin 86.0% and 80% and oxfendazole 78.3% and 100%, respectively. Posttreatment rise in FEC indicated that reinfection of moxidectin-treated animals occurred at the same time as oxfendazole controls in both trials. Posttreatment rise in FEC with ivermectin pour-on was similar to moxidectin and oxfendazole in one study, but in the other study ivermectin pour-on delayed the rise by 14-21 days. The rise in FEC for doramectin was delayed for 14-21 days in one study and at least 21 days in the other. The better parasite control provided by doramectin resulted in greater weight gains for cattle over the 56-day period as compared to moxidectin pour-on, ivermectin pour-on and oxfendazole in both trials. Gains of doramectin treated cattle were significantly (p < 0.05) greater than those of ivermectin and moxidectin groups in one trial and the oxfendazole group only in the other.

Inhibitory action of verapamil and chlorpromazine on the release of slow-reacting substance of anaphylaxis from cat lung.

Verapamil, a calcium channel blocker, significantly inhibited the release of slow-reacting substance of anaphylaxis (SRS-A) from cat lung fragments challenged with either the calcium ionophore, A23187, or Ascaris extract. This effect was observed when verapamil was present at the concentrations of 10 microM and 50 microM. Chlorpromazine 10 microM significantly inhibited antigen-induced SRS-A release. Histamine release was low and no significant effect by verapamil or chlorpromazine could be shown.