Osseous development and tibial dyschondroplasia in five lines of turkeys.

Tibiotarsi and femurs from five genetic lines of turkeys from 8 to 39 weeks of age were examined to define the characteristics of normal bones. Bone lengths and body weights are presented. Tibial dyschondroplasia (TD) frequently was detected on gross examination and by high-detail radiography. The incidence of TD peaked at 12 weeks of age, when 79% of the toms were affected. This incidence rate dropped until the age of closure of the proximal tibial physis (22 to 24 weeks in toms) but remained 5 to 15%. Deformities of the tibiotarsi were frequently associated with TD in older toms. The incidence of TD and tibiotarsal deformities was highest in toms of the heaviest line.

"Field rickets" in turkey poults: field observations and pathological, radiological, and serological findings.

Two field cases of field rickets in turkey poults were studied. The primary observation was lameness, and the sole necropsy finding of significance was hypomineralization of bone. This finding was confirmed radiographically; thin cortices and wide growth plates were noted. Microscopically, there was failure of osteoid mineralization, failure of orderly progression from cartilage to bone in the growth plate, the formation of bony trabeculae perpendicular to the long axis of the bone, and fibroplasia in marrow spaces. On a routine serological screen for mycoplasma and several viruses, there were no differences between affected and normal poults from the same flock.

Field rickets in turkey poults: biochemical findings.

Two clinical cases of field rickets and one of nutritional rickets in turkey poults were studied. Plasma levels of calcium, phosphorus, alkaline phosphatase, and vitamin D metabolites were determined. Concentrations of calcium, phosphorus, and alkaline phosphatase in affected poults were typical of nutritional rickets. The mean plasma calcium concentration in rachitic poults was not significantly different from that in controls. Mean values for plasma phosphorus were 1.5 to 2.4 mg/dl lower in the rachitic poults, and values for alkaline phosphatase activity were 1.3-1.7 times greater. In assays of vitamin D metabolites, mean 24, 25 dihydroxyvitamin D3 values were consistently lower in rachitic poults.

Health and metabolic responses of young calves housed at -30 degrees C to -8 degrees C.

Newborn, male, Holstein calves, were continuously housed for three weeks in calf hutches at 17 degrees C or in a thermal environment which varied rhythmically on a daily basis either between -20 degrees C and -8 degrees C (experiment A) or between -30 degrees C and -18 degrees C (experiment B). Compared to warm-housed calves, cold-housed calves in experiment A had metabolic rates which were significantly higher (p less than 0.001) in a standing position but which were not significantly different (p less than 0.05) in a recumbent position. Recumbent and standing cold-housed calves in experiment B had an increased (p less than 0.05) metabolic rate compared to warm-housed controls. Heat loss was less (p less than 0.05) for recumbent cold-housed calves in experiment B than for standing calves in a thermoneutral environment. Localized subcutaneous hemorrhages of hindlimbs were a consistent necropsy finding among all cold-housed calves. Average daily gains of cold-housed calves were not significantly different from warm-housed controls. Clinical, physiological and pathological findings indicated that cold treatments used in the present study did not cause serious harm to calves. It was concluded that calves housed in properly managed hutches are remarkably cold tolerant.

Thermal insulation of young calves exposed to cold.

Tissue, external and whole animal insulation values were determined for 12 newborn male Holstein calves continuously housed for two weeks in hutches within environmental chambers in which temperature was maintained at a constant 17 degrees C (three calves) or cycled on a daily basis either between -20 degrees and -8 degrees C (three calves) or between -30 degrees and -18 degrees C (six calves). Three of the six calves at the coldest temperature were outfitted with an insulated coat. The insulated coat provided calves a 52% increase in total insulation. Tissue insulation of cold-housed calves increased 37.2% over the first two weeks of life. It was concluded that the capacity for vasoconstriction improved with age. External insulation did not change significantly except during the first week in cold-housed calves without insulated coats. External insulation values were five to eight times those of tissue insulation values for all treatment groups. This indicated that insulation of structures external to the skin (hair, bedding, ground, etc.) provided most of the insulation for calves.

Myometrial activity during natural and dexamethasone-induced parturition in the cow.

Myometrial activity was monitored during natural and dexamethasone-induced parturition in 8 Holstein dairy cattle, using strain gauge transducers. Four gauges were attached to the serosal surface of the gravid uterine horn, dividing it into thirds. Parturition was induced in 2 of 4 heifers and 2 of 4 cows (group 1); the remaining animals were allowed to calve spontaneously (group 2). Chains of low-amplitude contractions (repeated small deviations from base line) were detected before parturition was induced, and these were more common at distended parts of the uterus. Uncharacteristically sharp peaks followed by small rhythmic contractions, during preinduction recording, indicated that the myometrium was responsive to fetal movement even several days before parturition. By 18 hours before parturition, discrete single contractions appeared independently of contraction chains, and the first tubocervical peristaltic contraction waves were detected. The mean area under recorded contraction curves (uterine work) increased quadratically and the frequency of contractions decreased linearly from 12 hours before parturition to 2 hours after parturition. There was also an increase in the proportion of tubocervical waves over this period, and contraction chains were no longer present. During the second stage of labor, distended and undistended parts of the uterus were equally active, and forceful maternal straining was associated with larger sustained contractions. Fetal membrane rupture was accompanied by a doubling in the rate of passage of contraction waves along the length of the uterus. After the calf was expelled, contractions became extremely regular, and the majority progressed in a tubocervical direction.(ABSTRACT TRUNCATED AT 250 WORDS)

Energy metabolism and hematology of white-tailed deer fawns.

Resting metabolic rates, weight gains and hematologic profiles of six newborn, captive white-tailed deer (Odocoileus virginianus) fawns (four females, two males) were determined during the first 3 mo of life. Estimated mean daily weight gain of fawns was 0.2 kg. The regression equation for metabolic rate was: Metabolic rate (kcal/kg0.75/day) = 56.1 +/- 1.3 (age in days), r = 0.65, P less than 0.001). Regression equations were also used to relate age to red blood cell count (RBC), hemoglobin concentration (Hb), packed cell volume, white blood cell count, mean corpuscular volume, mean corpuscular hemoglobin concentration (MCHC), and mean corpuscular hemoglobin. The age relationships of Hb, MCHC, and smaller RBC's were indicative of an increasing and more efficient oxygen-carrying and exchange capacity to fulfill the increasing metabolic demands for oxygen associated with increasing body size.

Bioavailability of phosphorus in commercial phosphate supplements for turkeys.

Forty-seven commercial phosphorus supplements were obtained from feed manufacturers and subjected to biological phosphorus availability assay using the turkey poult. Bone ash was the response criterion. Compared to a reference source of commercial mono/ dicalcium phosphate (assigned 100), 7 other mono/ dicalcium phosphates averaged 97.1 (range 88.6 to 110.0), 20 dicalcium phosphate sources averaged 90.6 (76.3 to 104.8), and 20 defluorinated phosphate sources averaged 78.4% (68.6 to 89.6) availabilities. Combining equal parts of all sources of each type of phosphorus supplement and using purified grade calcium phosphate monobasic monohydrate as a defined standard, the commercial mono/ dicalcium phosphates, dicalcium phosphates, and defluorinated phosphates averaged (with 95% confidence limits) 93.6 +/- 7.6, 88.3 +/- 8.2, and 70.2 +/- 7.2% phosphorus availability in a slope ratio bioassay. Calculating the requirement intercepts utilizing the blended phosphorus supplements indicated apparent requirements using mono/ dicalcium phosphate, dicalcium phosphate, and defluorinated phosphate of .74, .76, and .83% total phosphorus in the diet, respectively. Considering 1) the variability in availability of the sources, 2) variation in feed mixing, 3) the National Research Council requirement of .80%, and 4) that newly hatched poults are completely dependent on one batch of prestarter feed during 0 to 10 days of life, it is suggested that in certain instances field rickets could result from deficiency of dietary phosphorus.

Studies of methods for in situ observation of gastric motility in domestic turkeys.

The normal gastroduodenal contraction cycle of turkeys is believed to be controlled and coordinated by the myenteric plexus which lies just under the serosa of the muscular stomach. Methods which would permit direct application of chemical and physical stimuli to these gastric nerves were studied in intact and decerebrate turkeys using both radiographic and direct observations to monitor contraction cycles. In intact turkeys, general anesthetics (sodium pentobarbital, halothane; and ketamine hydrochloride) inhibited gastric motility. A local anesthetic (lidocaine hydrochloride) injected into the skin and abdominal muscles caused a depression of motility. In both intact and chronically decerebrate turkeys laparatomy (after local anesthetic in intact birds) and a neuromuscular blocking agent (gallamine triethiodide) also depressed gastric motility. Motility was slightly reduced by artificial respiration and exposure of the serosal surface of the stomach and intestines to air via an abdominal fistula.

Acquired resistance in turkey poults to Pasteurella multocida (P-1059 strain) during aflatoxin consumption.

The potential for impairment by aflatoxin of the development of acquired immunity to fowl cholera in 8 week old turkey poults from a commercial flock was investigated by challenge of vaccinated poults at 10, 12, and 16 weeks of age. Sixty poults were allotted to 4 groups: A) aflatoxin fed, nonvaccinated; B) aflatoxin fed, vaccinated; C) control fed, nonvaccinated; and D) control fed, vaccinated. Aflatoxin B-1 (.5 ppm) was added to the control ration of groups A and B from 49 to 70 days of age. The avirulent CU (Clemson University) strain of Pasteurella multocida drinking water vaccine was given for one day to groups B and C. Challenge (5 poults from each group) was by administration of the virulent (P-1059) strain of P. multocida in the drinking water for 4 consecutive days. The presence of aflatoxin B-1 (.5 ppm) in the feed during oral vaccination with the avirulent strain of P. multocida did not impair the development of acquired resistance to later challenge with the virulent strain. Results indicate that age of poults and method of vaccination may be important factors in the development of acquired resistance to fowl cholera when aflatoxin is present in the diet.

Digestive parameters in young turkeys fed yucca saponin.

Yucca saponin fed in a concentration of 63 ppm to turkey poults at 6 to 14 weeks of age did not significantly improve weight gains, feed conversion, or digestive coefficients. Compared with nonstressed control groups, saponin-fed poults did not have significantly greater average weight gains or feed intakes when stressed by crowding (3 poults per cage) or by adding ammonia to the atmosphere (30 to 35 ppm).

Effect of dietary sodium fluoride on growth and bone development in growing turkeys.

Large White male turkeys were fed rations containing 0, 12.5, 25, 50, 100, 200, 400, and 800 ppm added fluoride (F) from sodium fluoride in a corn-soybean assay diet containing tricalcium phosphate and 3 to 5 ppm F. The 800 ppm treatment was discontinued at 8 weeks because of low weight gains and a high incidence of leg disorders. Turkeys receiving defluorinated phosphate (32% calcium, 18% phosphorus) had significantly higher 4-week body weights than turkeys receiving tricalcium phosphate. Turkeys fed 0, 400, and 800 ppm F had significantly lower body weights at 8 weeks than turkeys fed 50 ppm F. A similar weight pattern was seen at 18 weeks, although the differences were not statistically significant. Based on growth response in this study, a requirement of 20 ppm F is proposed. Increasing levels of dietary F resulted in large increases in tibia F. Removal of high dietary F in certain groups at 8 weeks resulted in growth recovery and reduction in tibia F by 18 weeks. Elevated plasma alkaline phosphatase activity was observed with added dietary F of 400 and 800 ppm. At 4 weeks, tibiae from turkeys receiving high F had a trend (not statistically significant) toward lower percentage ash and a significantly lower breaking strength than controls. Compared to controls, tibiotarsi from turkeys on high F rations were significantly shorter, had thinner cortices, and had a narrower proliferative zone of proximal growth plates. A high incidence of tibial dyschondroplasia was observed, but it was not correlated with dietary treatment.