Serum antibody response to Mycoplasma hyopneumoniae measured by enzyme-linked immunosorbent assay after experimental and natural infection of pigs   总被引：1，自引：0，他引：1  

RF SHELDRAKE  IA GARDNER  MM SAUNDERS  LF ROMALIS 《Australian veterinary journal》1990,67(2):39-42

Studies were conducted under experimental and field conditions to determine the effect of infection with M. hyopneumoniae on the immune response in serum as measured by ELISA. Following intratracheal challenge or contact exposure, serologically negative pigs derived from mycoplasma-free piggeries developed an immune response within 10 days. This response continued to rise for a further 50 days. In a field study in a commercial piggery, no animals (0/44) were observed to have M. hyopneumoniae antibodies at day 86 of life. However between day 86 and day 144, 97.7% (42/43) animals sero-converted. These results are discussed in terms of infection spread, particularly in the grower/finisher shed.  相似文献   

Beef quadriceps hot boning and modified-atmosphere packaging influence properties of injection-enhanced beef round muscles     

Seyfert M  Hunt MC  Mancini RA  Hachmeister KA  Kropf DH  Unruh JA  Loughin TM 《Journal of animal science》2005,83(3):686-693

Two experiments were conducted to examine the effects of hot boning, modified atmosphere packaging, and injection enhancement on the oxidative and sensory properties of beef round muscles. The beef knuckle (quadriceps muscles) was partially hot boned within 1.5 h postmortem from one randomly selected side of each beef carcass (n = 14), whereas the quadriceps on the opposite side remained intact throughout a 48-h chilling period. At 5 d postmortem, biceps femoris, semimembranosus, vastus lateralis, and rectus femoris muscles from both hot- and cold-boned sides were injected with an enhancement solution consisting of water, salt, phosphate, and natural flavorings (rosemary) at either 6 (Exp. 1) or 10% (Exp. 2) of fresh muscle weight. Enhanced muscles were then processed into 2.54-cm-thick steaks, which were allotted randomly to high-oxygen (HiOx; 80% O2:20% CO2) or ultra-low oxygen (LoOx; 80% N2:20% CO2) modified atmosphere packaging. Regardless of hot boning or enhancement, steaks packaged in LoOx had lower thiobarbituric acid-reactive substances values (P < 0.05), more beef flavor intensity (P < 0.05), fewer off flavors (P < 0.05), and were more tender (P < 0.05) than steaks packaged in HiOx. Hot boning the knuckle had no effect on oxidative (P > or = 0.99) and sensory properties (P > or = 0.85). Increasing the level of injection enhancement from 6 to 10% introduced more rosemary and phosphate into the muscles, thereby decreasing the extent of oxidation, but also imparting a nontypical beef flavor. Packaging in LoOx atmosphere offered the optimal result of decreased oxidation and improved tenderness, without detriment to flavor. Injection enhancement (both 6 and 10%) created off-flavors attributable to the enhancement solution; however, the 10% injection seemed to offer more resistance to lipid oxidation.  相似文献   

Mechanical probes can predict tenderness of cooked beef longissimus using uncooked measurements     

Stephens JW  Unruh JA  Dikeman ME  Hunt MC  Lawrence TE  Loughin TM 《Journal of animal science》2004,82(7):2077-2086

Two experiments were conducted to determine the effectiveness of using mechanical probes and objective color measurement on beef LM to predict cooked tenderness. In Exp. 1, sharp needle (SN), sharp blade (SB), blunt needle (BN), blunt blade (BB), and plumb bob (PB) probes were used to measure uncooked LM (n = 29) at 2 d postmortem in both a perpendicular and parallel orientation to the long axis of the strip loin. Additionally, instrumental color measurements were measured on uncooked muscle at 2 d postmortem. Steaks for trained sensory panel (TSP) and Warner-Bratzler shear force (WBSF) measurements were aged 14 d postmortem before cooking. Probe measurements taken perpendicular to the long axis of the LM were not correlated (P = 0.22 to 0.82) to TSP tenderness. Probe measurements (BB, BN, SN, SB, and PB) taken parallel to the long axis were correlated to TSP tenderness (r = -0.57, -0.40, -0.77, -0.52, and -0.53, respectively). A regression equation using the SN probe to predict TSP tenderness had a R2 value of 0.74. The SB probe combined with L* accounted for 45% of the variation in TSP tenderness, whereas the PB probe combined with L* accounted for 56% of the variation in TSP tenderness. A second experiment (n = 24) was conducted using the SN, SB, and PB probes on uncooked sections at 2 d and on cooked steaks at 14 d postmortem. Probe measurements on cooked steaks were not correlated to TSP tenderness. New regression equations were calculated using the probe measurements on uncooked steaks from both experiments. Prediction equations formulated with L* values and either SN, SB, or PB probes accounted for 49, 50, and 47% of the variability in TSP tenderness scores, respectively. An equation using WBSF of cooked steaks to predict TSP tenderness had an R2 of 0.58. Of the steaks predicted to be tender (predicted tenderness > 5.0) by the equations using the SN, SB, and PB probes on uncooked steaks and WBSF on cooked steaks, 85, 88, 80, and 84%, respectively, were actually tender (TSP tenderness > 5.0). Mechanical probe measurements of uncooked steaks at 2 d postmortem can potentially classify strip loins into groups based on tenderness, as well as WBSF measurements, which are more costly and time consuming.  相似文献   

Differentiation of Australian isolates of Mycobacterium paratuberculosis using pulsed-field gel electrophoresis     

MM FEIZABADI  ID ROBERTSON  A HOPE  DV COUSINS  DJ HAMPSON 《Australian veterinary journal》1997,75(12):887-889

Objectives To examine strain variation amongst Australian isolates of Mycobacterium paratuberculosis .
Design Pulsed field gel electrophoresis was optimised for differentiation of M paratuberculosis strains, and this typing technique was then applied to a collection of Australian isolates.
Procedure DNAs from 35 Australian isolates of M para-tuberculosis and a UK reference strain were digested with one or other of three restriction endonucleases. The banding patterns obtained after pulsed field gel electrophoresis of the DNA fragments were compared.
Results The Australian isolates were divided into two groups on the basis of their DNA banding pattern. Both were different from the UK reference strain. Seven isolates from cattle in Victoria and the Northern Territory had the same pattern as five isolates from alpacas in Victoria and Western Australia. Another 20 isolates from cattle in Victoria, Western Australia and the Northern Territory had the same pattern as isolates from two sheep and a goat in New South Wales.
Conclusion Pulsed field gel electrophoresis was a useful tool for strain typing of M paratuberculosis , and could be used to study the transmission of strains in Australia.  相似文献   

Comparison of Stereoscopy, Light Microscopy and Ultrastructural Methods for Evaluation of Bovine Embryos   总被引：2，自引：0，他引：2  

MM Aguilar  CS Galina  H Merchant  F Montiel  R Canseco  YC Márquez 《Reproduction in domestic animals》2002,37(6):341-346

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Effect of Acute Bull Exposure Around the Time of Artificial Insemination on Serum Oxytocin and Progesterone Concentrations and Pregnancy Rates in Dairy Cows     

MM Ababneh  IN Obeidat  MQ Husein  AQ Talafha 《Reproduction in domestic animals》2013,48(2):223-230

This study examined the effect of acute bull exposure around the time of artificial insemination (AI) on oxytocin and progesterone concentrations, and pregnancy rates in dairy cows. Ninety six dairy cows, stratified according to parity into primiparous and pluriparous, were divided into three groups; short bull exposure (SBE; 10 min, n = 32), long bull exposure (LBE; 4 h, n = 32) or no bull exposure (NBE; n = 32). On day 45 post‐partum, all cows were treated with PGF2α on three occasions 11–14 days apart to synchronize oestrus. They were submitted to fixed time AI 80 h after the third PGF2α injection. Cows in the SBE and LBE groups were artificially inseminated 5 min after the introduction of the bull. From a subset of cows (n = 6 per group; three primiparous and three pluriparous), blood samples were collected once every 5 min starting 15 min before AI until 15 min after AI and analysed for oxytocin concentrations. Additional blood samples were collected for measurements of progesterone (P4) concentrations once daily for 4 days starting on the day of AI and once every 3 days thereafter until day 22. The effects of bull exposure, time, parity, difficulty of AI, and pregnancy on oxytocin and P4 concentrations were analysed using the mixed linear model procedure. Mean oxytocin concentrations or change in oxytocin concentrations after bull exposure or AI were not different among groups. Pregnancy rates for the NBE, SBE and LBE groups were 55.5%, 33.3% and 44.4%, respectively, and were not different among groups. In conclusion, acute bull exposure around the time of AI did not affect oxytocin and progesterone concentrations and did not improve pregnancy rates in dairy cattle under these farms conditions.  相似文献   

Nutritional and Economic Implications of Protein Variance and Application of Statistical Process Control in the Chinese Feed Industry     

Zhichun Yan  Timothy J. Herrman  Thomas Loughin  Allen M. Featherstone  Dingyaun Feng 《Cereal Chemistry》2003,80(5):623-626

The adoption of Statistical Process Control (SPC) in the Chinese feed industry to reduce finished feed protein and moisture content variation can improve feed quality and profitability. Two studies were conducted to characterize protein variation in the Chinese feed industry. Study I involved four participating feed mills where we collected three samples per bag from four bags per lot of soybean meal, rapeseed meal, fish meal, corn gluten meal, meat & bone meal, and cottonseed meal. We analyzed these ingredients for protein and moisture content. Cottonseed meal and meat & bone meal displayed the highest protein variability between bags and within bags compared with other protein ingredients. We found no significant difference for within‐bag protein variance of the other feed ingredients; however, soybean meal had a significantly lower between‐bag variance (0.04%). Study II assessed the effect of adopting SPC. Five feed mills provided data for one year of finished feed protein and moisture content before and after adopting SPC. Three of the five feed mills experienced a significant (P < 0.10) reduction (0.20, 0.52, and 0.70%) in the absolute finished feed protein variation after adopting SPC. The two feed mills that did not display a significant reduction in absolute protein variation were already manufacturing feed with a low (<0.4% protein) absolute deviation from the target. These data demonstrate that feed mill managers can control finished feed variability through a number of management techniques including SPC.  相似文献