OBJECTIVE: To determine the survival time of Mycobacterium avium subsp paratuberculosis in amitraz-based cattle dip fluid derived from an active dip site in northern New South Wales. PROCEDURE: Following inoculation of triplicate 5 L containers with faeces (0.5 g/L) from a clinical case of bovine paratuberculosis, samples collected up to 8 weeks after inoculation were examined by conventional and radiometric culture. M a paratuberculosis colonies were enumerated on solid media. RESULTS AND CONCLUSIONS: M a paratuberculosis survived in amitraz cattle dip fluid for up to 2 weeks, but not 3 weeks. Where 1% of solids in dip fluid is derived from a clinical case of paratuberculosis, dip fluid may contain viable M a paratuberculosis for at least 2 weeks. These findings have implications for the management of cattle dip sites. 相似文献
1. Deep body temperature was measured daily in germ-free and conventional chicks from 1 to 16 of age. 2. The temperature of germ-free chicks rose rapidly during the first 4 d and thereafter only slowly, whereas that of conventional birds increased gradually throughout. 3. Body temperature attained by the germ-free birds was about 0.3 degrees C higher than that of conventional birds. 相似文献
A suitable procedure for obtaining blood samples was established from an investigation of (a) diurnal variations in plasma amino acid concentrations and (b) the effect of controlling food intake on plasma amino acid levels.
Restriction of feeding to a 40‐min period, 105 min before sampling, significantly increased total plasma amino acid levels (P< 0.05) and individual concentrations of serine and proline (P<0.05) and glycine (P<0.01). The cause of these changes is not clear. Amino acid concentrations in samples taken at different times during the day were fairly constant. In the sampling procedure adopted routinely, birds were allowed free access to their diets for two weeks and sampled at 14.00 h on day 14.
The effect of dietary lysine level, at two protein concentrations, on plasma amino acid levels was evaluated. With inadequate and excessive dietary lysine concentrations total plasma amino acid levels were generally elevated. Plasma levels were least with diets containing 0.9 to 1.15% lysine.
The lysine requirements for optimum performance measured by growth rate, food conversion efficiency and nitrogen retention were identified as 1.2% with a 21% protein diet and approximately o‐8% with a 16% protein diet. The data indicate that efficient utilisation of dietary protein and relatively low levels of amino acids in the plasma are fairly closely related. 相似文献
The purpose of this experiment was to study the effects of Gymnadenia conopsea polysaccharide (GCP) extract on growth performance, meat quality and antioxidant function house-fed mutton sheep under oxidative stress, so as to provide experimental basis for extensive research and development of Gymnadenia conopsea and its extracts. Twenty 6-month-old healthy male Small-Tailed Han sheep with body weight of (35.0 ±4.0) kg were randomly divided into two groups. The experimental group (n=10) and control group(n=10). The whole experiment lasted for 42 d and was divided into 3 periods: the first 15 days were the blank period; the middle 15 days were the treatment period; the last 12 days were the observation period ofter modeling. From the first day of the treatment period, the control group was fed with basal diet, and the experimental group was fed pellet basal diet containing 30 mg·kg-1 GCP extract. On the 15th day of the treatment period, the sheep in each group were intraperitoneally injected with 10 mg·kg-1 Diquat solution according to sheep body weight(BW), and then fed for another 12 days. On the 1 st, 15th, 30th, 33rd, 36th, 39th and 42nd morning of the whole experimental period, fasting weight and blood samples were collected before feeding. The serum was separated and the antioxidant indexes (SOD, GSH-Px, T-AOC, MDA) in serum were determined. On the 42nd day of the whole experimental period, 5 sheep randomly selected from each group were slaughtered and meat samples were collected to determine the meat quality. The results showed that the addition of GCP extract to the diet of the sheep could increase the average daily feed intake (P<0.05). When the body was subjected to oxidative stress, the indexes of daily gain and antioxidant enzymes recovered rapidly on experimental group, the mutton drip loss decreased significantly, and the mutton sheer force increased significantly(P<0.05). The results indicated that GCP extract could improve the growth performance of mutton sheep, and alleviated the decline of growth performance and antioxidant performance caused by oxidative stress, and had a certain effect of antioxidant stress. 相似文献