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951.
Compensatory growth following metabolizable protein or energy restrictions in beef steers 总被引:2,自引:0,他引:2
J S Drouillard C L Ferrell T J Klopfenstein R A Britton 《Journal of animal science》1991,69(2):811-818
One hundred sixty crossbred steers were used to compare the effects of metabolizable protein and energy restrictions on subsequent compensatory growth. Diets were formulated to impose severe or mild growth restrictions for periods of 77 to 154 d. Steers were realimented on a high-concentrate diet and fed to achieve approximately 1 cm s.c. fat thickness. Finishing performance and carcass characteristics were evaluated relative to unrestricted control animals. All restricted animals, with the exception of those on the mild, brief energy restriction, exhibited compensatory growth relative to controls. A single direct comparison of energy and protein restriction treatments indicated that finishing performance during realimentation was similar for these two groups. Evaluation of the relative effects of protein and energy restriction by multiple linear regression indicated that compensatory growth was influenced by differences in duration or severity of nutrient deprivation to a greater extent for energy-restricted than for protein-restricted steers. Linear contrasts and regression estimates indicated that compensatory growth was influenced more by differences in severity of restriction than by duration of the restriction period. 相似文献
952.
953.
A.E. Wanger DVM MS W.W. Muir III DVM Phd R.M. Bednaraki DVM MS 《Journal of Veterinary Emergency and Critical Care》1991,1(1):14-18
The purpose of this study was to determine whether lingual vanous blood gas samples reflect arterial acid-base gas status in anethetized dogs. Heparinized blood samples were drawn simultaneously from the lingual vein and a peripheral artery in 50 anestheized dogs that were clinical surgical patients, as well as from four experimental dogs in which hemorrahaic shock was being studied. Blood pH, oxygen tension (PO2 ), and bicarbonate (HCO3- )) from the two sources in clinical patients showed significant liner correlation, although arterial PO2 )(PaO2 )) tended to be approximately 110mm Hg higher than lingual venous PO2 ). During hemorrahgic shock, however, PaO2 ) and PaCO2 ) were significantly different from lingual venous PO2 ) and PCO2 ), Lingula venous blood gas analysis may be useful in assessing acid-base and blood gas status in routline cases, but should not be relied upon in dogs with low cardiac output or poor perfusion. 相似文献
954.
955.
Thirty-six mice were inoculated intranasally with Bordetella parapertussis organisms (isolated from sheep with chronic non-progressive pneumonia) to study their deposition and clearance in the lower respiratory tract. The deposition of the organism was greater in the trachea than in the lungs. At 48 hours after inoculation, almost 100% of organisms were cleared from the trachea but only 55% of organisms were cleared from the lungs. This result correlates well with the morphological changes seen previously in the pulmonary parenchyma and airways of mice and lambs experimentally infected with this organism. 相似文献
956.
The early diagnosis of bovine leukosis virus (BLV) infection, the aetiological agent in enzootic bovine leukosis, is important for the implementation of control measures. BLV infection is currently assessed by the detection of circulating antibodies against the viral envelope protein, gp51. However, this approach has shortcomings in the time taken to detect anti-BLV antibodies (three to four weeks after infection), and in the failure to detect antibodies in some animals. Clearly a technique such as the polymerase chain reaction (PCR), which directly detects the presence of viral DNA, has advantages over methods designed to measure host antibodies. The use of PCR for the detection of proviral DNA in an affected DNA sample with as little as 10(-5) micrograms of host DNA using agarose gel electrophoresis followed by ethidium bromide staining is described here. It was possible to improve the sensitivity of this assay by using hybridisation analysis with a BLV gene probe. PCR used in combination with hybridisation analysis will provide a sensitive diagnostic assay to detect BLV when antibody tests give weakly positive or equivocal results. 相似文献
957.
S J Duffy R B Morrison D G Thawley 《Journal of the American Veterinary Medical Association》1991,199(1):61-65
In theory, pseudorabies virus (PRV) may be eliminated from any size of breeding herd by phased test and removal if replacement gilts are not infected with PRV, culling decisions are partially based on PRV status, and the cull rate is higher than the incidence rate of PRV. Annual cull rates are commonly at least 50%, but little information exists on the incidence of PRV within enzootically infected swine herds. The purpose of this study was to develop a method by which spread of PRV could be detected among breeding swine within enzootically infected herds and to determine the incidence of PRV infection in these herds. Data were collected from 17 herds that were quarantined for PRV and ranged in size from 120 to 1,100 sows. At each herd, within the first 5 days of introduction, a group of approximately 30 replacement gilts was identified, vaccinated with a glycoprotein X-deleted PRV vaccine, and blood sample was collected. The owner of 1 herd had a nonvaccinated breeding herd and elected to leave incoming gilts nonvaccinated. After vaccination, blood samples were collected every 1 to 2 months for an average of 13.6 months. Serum samples from vaccinated gilts were tested for antiglycoprotein X antibodies by a specific differential ELISA. Samples from nonvaccinated gilts were evaluated by serum neutralization test. Product-limit method was used to estimate the probability of not becoming infected with PRV. Spread was detected in 7 of 8 herds that had more than 400 sows and in 2 of 9 herds that had less than 400 sows.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
958.
D G Atwell N R Merchen E H Jaster G C Fahey L L Berger 《Journal of animal science》1991,69(4):1697-1706
Five crossbred wethers (58 kg) fitted with cannulas in the rumen, duodenum, and ileum were used in a 5 x 5 Latin square design to study effects of feeding combinations of alkaline hydrogen peroxide-treated wheat straw (AHP-WS) and alfalfa hay at restricted intakes on site and extent of nutrient digestion. Additionally, flows and disappearance of N and amino acids (AA) in the small intestine were regressed on alfalfa nitrogen intake (ANI) to estimate alfalfa's contribution to postruminal N and AA supplies. Diets consisted of 80:20 forage:concentrate mixtures; diet designations were 80:0, 80% AHP-WS and no alfalfa; 60:20, 60% AHP-WS and 20% alfalfa; 40:40, 40% AHP-WS and 40% alfalfa; 20:60, 20% AHP-WS and 60% alfalfa; and 0:80, no AHP-WS and 80% alfalfa. A modest positive quadratic (P less than .05) response was noted for total tract digestibility (TTD) of OM; values were 76.5% for diets 80:0 and 0:80 vs 78% for diet 40:40. Ruminal digestibility (percentage of intake) of NDF and ADF increased in a quadratic manner from 43 and 30%, respectively, for diet 0:80 to 71 and 70%, respectively, for diet 80:0. Ruminal digestibility of fiber may have been enhanced due to linear (P less than .05) decreases in liquid and particulate dilution rates, resulting in increased ruminal residence time of fiber as alfalfa hay replaced AHP-WS. Liquid and particulate dilution rates decreased linearly from 6.4 and 5.2%/h, respectively, for diet 80:0 to 5.4 and 3.4%/h, respectively, for diet 0:80. Regression analysis of N data indicated that alfalfa N had a ruminal escape value of 26%. 相似文献
959.
960.
In situ neutral detergent insoluble nitrogen as a method for measuring forage protein degradability.
A method of estimating the undegraded intake protein (UIP) concentration of forages was developed and validated with a series of in situ experiments. The hypothesis was that UIP calculated from in situ neutral detergent insoluble N (NDIN) is equal to total in situ N minus the microbial N that is estimated from purines (MN). The in situ disappearance rates of total in situ N (TN), MN, and NDIN were measured for six hay samples and two range masticate samples. Hypothetical rates of passage (2 or 5%/h) were used to calculate UIP (% of DM) for each N pool. Estimates of UIP from TN were higher (P = .0001) than those from either MN or NDIN, and MN estimates of UIP were similar (P = .48) to NDIN estimates. A low-N fiber source (solka floc) was incubated in situ for 8 h. Analysis of the residue detected purines before, but not after, neutral detergent extraction. Several in situ incubation (i.e., Dacron bag size and number of Dacron bags in a mesh bag) and neutral detergent extraction conditions were tested. None of the factors tested affected in situ NDIN disappearance (P > .05). The hypothesis that NDIN is completely digestible in the rumen was tested. Estimates of the extent of NDIN digestion were made using 96-h in situ incubations, and UIP was recalculated for the test samples. Mean in situ UIP concentration decreased upon recalculation (P = .05). In situ NDIN provides estimates of forage UIP that are equal to estimates from MN. Forage UIP estimates are less when extent of N degradation is estimated and included in the calculation. 相似文献