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A Meltzer

Publications and source records attributed to A Meltzer.

35 records · Page 2Linked to original sources
PubMed1984

Patterns of peripheral vasomotor function in near-natural conditions in the calf (Bos taurus).

Patterns of ear temperatures were examined in 2- to 45-day-old calves. At variable heat loads, peripheral temperature levels varied with the heat load with little fluctuations. When 2 to 3 days old, high ear temperatures were maintained for 10-14 hr/day at 10-15 degrees C ambient temperatures in 5 of 8 calves. In near-natural conditions, fluctuating ear temperatures were the rule in the vasodilated, intermediate and vasoconstricted states; fluctuations were symmetrical in the two ears in the vasodilated and intermediate states only. The possible occurrence of cold-induced vasodilation at 10-20 degrees C ambient temperature is discussed.

Aging↗
PubMed1984

An improved method for obtaining semen from Muscovy drakes and some of its quantitative and qualitative characteristics.

An improved method for obtaining semen from the Muscovy drake using an "artificial vagina" was developed and employed on a commercial scale. With such a procedure, the ejaculate volume was 1.12 +/- .85 ml, semen concentration was 1.35 +/- .43 X 10(9) cells/ml with 8.6 +/- 6.3% abnormal sperm cells. Average spermatozoal motility was graded as 3.59 +/- .93 on a scale of 0 to 5 and the initial pH was found to be 7.30 +/- .23 within 5 min of ejaculation.

Animals↗
PubMed1983

Thermoneutral zone and resting metabolic rate of broilers.

Metabolic rate was determined once a week in broilers from a commercial source, from 1 to 63 d of age. The equations relating minimal resting metabolic rate (oxygen consumption, ml/bird h, y) and body weight (W) were: males 45 to 497 g, y = 3.2 W0.882; 597 to 3000 g, y = 40.5 W0.483; females 45 to 514 g, y = 2.52 W0.881; 514 to 2500 g, y = 12.3 W0.627. The relationship between lower critical temperature (Tcl, degree C, y) and age (d, x) may be described by the following equations: chicks 1 to 21 d, y = 34.2 - 0.32 x; 14 to 63 d, y = 49.4 x -0.194. The relationship between Tcl and W may be described by one equation for both sexes between 100 and 3000 g, y = 62.15 W-0.135. The equations for Tcl and data for upper critical temperature (Tcu) could be used to obtain maximal performance from broilers, with reduced costs, by providing a suitable environment related to age or body weight.

Animals↗
PubMed1983

The effect of body temperature on the growth rate of broilers.

The effect of body temperature (Tb) on the growth rate of male broilers was studied. Two pens (5 m2 each), one (A) near air inlets and one (B) near air outlets, were erected in a 12.5 m wide cross-ventilated, environmentally-controlled poultry house. Of 100 birds of both sexes in each pen, 18 males were marked and weighed weekly, and in three of these in each pen body temperature was measured by telemetry over 24 h at 50, 54, 55, 58, and 62 d of age. At 62 d group B birds weighed 250 g less than A; implanted birds weighed less than their group means, but relative growth rates were similar. Mean lowest (08.00 to 09.00 h) and highest Tb (11.00 to 17.00 h) in group A were 41.35 degrees C and 42.13 degrees C, and in group B 41.48 degrees C and 42.86 degrees C, respectively. The regression of G (percentage gain in body weight/d) on noon maximum Tb (Tbn) was G = 46.25 - 1.024 Tbn. This study suggests that an air temperature above 32 degrees C depresses body-weight gain of broilers by about 10% between 5 and 9 weeks of age. Therefore, house temperature should not be allowed to increase above 28 degrees C, except if relative humidity also increases to 0.70 or more.

Animals↗
PubMed1982

Thermoneutral zone and resting metabolic rate of growing White Leghorn-type chickens.

1. Metabolic rate was determined once a week in pullets from commercial flocks of the local White Leghorn strain from the age of 1 d to 13 weeks. 2. The equations relating minimal resting metabolic rate and body weight were: for body weights of 40 to 163 g Y = 1.83 W0.986, and for 163 to 1 200 g Y = 11.64 W0.623, where Y = O2 consumption (ml/bird h) and W = body weight (g). 3. The relationship between lower critical temperature (Tcl) and age may be described by two equations: for pullets of 1 to 21 d of age Y = 35 - 0.286 X, and for 21 to 70 d of age Y = 63.3 X-0.254, where Y = Tcl (degrees C) and X = age (d). 4. Tcl related to body weight is also described by two equations: for body weights of 40 to 163 g Y = 42 - 1.18 W0.480, and for 163 to 800 g Y = 42 - 3.60 W0.260. 5. These equations could be used to calculate the Tcl on a day-to-day basis related to age or body weight.

Animals↗
PubMed1980

The thermoneutral temperature zone and seasonal acclimatisation in the hen.

1. Oxygen consumption, body temperature, respiratory frequency and respiratory water loss of White Leghorn x Rhode Island hens were measured for short periods at six air temperatures between 2 and 32 degrees C. The hens were kept between tests in an open shed. The experiments were carried out over 3 years. 2. The upper critical temperature (Tcu) was estimated by the air temperature at which: 1, respiratory frequency increased above 60 respirations/min and 2, body temperature increased by 0.3 degrees C above that at the lower critical temperature. These responses to the test temperatures were examined as a function of the acclimatisation temperature (Ta) represented by the mean daily temperature during experimental periods. 3. A seasonal change in Tcu was observed, which correlated with Ta(r = 0.836). The seasonal 10 degrees C change in the Ta brought about a 3 degrees C change in Tcu, compared with an 8.5 degrees C change in the lower critical temperature. 4. Thermoneutral temperature zone decreased with increasing Ta; the two critical temperatures tended to merge at a Ta of 32 degrees C. The latter probably represents an upper limit for acclimatisation to heat.

Animals↗
PubMed1979

Seasonal acclimatisation in the hen.

1. The oxygen consumption and body temperature of White Leghorn x Rhode Island Red laying hens, which were being kept in a semi-natural climate, were periodically measured for short periods at ambient temperatures between 2 and 32 degrees C in a suitable chamber. 2. A seasonal shift was observed in lower critical temperature (Tc) and thermoneutral oxygen consumption. The slope of the relationship between oxygen consumption and air temperature at less than Tc was not discernibly affected by season. 3. The seasonal shifts correlated best with mean daily outside temperature Ta) during the experimental periods; a seasonal decrease of 10 degrees C in Ta was associated with a decrease of 8.5 degrees C in Tc and a 12% increase in thermoneutral oxygen consumption. 4. The capacity to maintain body temperature stability at extremes of environmental temperature was improved by acclimatisation to heat.

Acclimatization↗
PubMed1978

Metabolic rate: its circadian rhythmicity in the female domestic fowl.

1. In quasi-natural cyclic lighting, a circadian rhythm was observed in seven fowls; the range of oscillation of the rhythm was 50% of the mean metabolic level. Little variation was present between the individuals. 2. In fowls maintained for 15 days in isolation under 700 lx (ten fowls) or 0.07 lx (four fowls) constant lighting and at constant temperature free-running rhythms were evident; the range of oscillation was about 12% of the mean level. Large variation prevailed between the individuals in the range of oscillation and in the portion of variance accounted for by periodic regression. In dim light, rhythmicity declined to become non-significant by 8 days of exposure. 3. In four fowls maintained in a 6L/6D regimen for 12 days, metabolic rate was entrained to an ahemeral rhythm; there was no evidence of circadian influence on the metabolic response to light. Little variation was present between the individuals. Rhythmicity was maintained over the experimental period. 4. Metabolic levels were similar on 0.07 lx, 700 lx constant light, during the dark phase of the 6L/6D regimen and during night time in the quasi-natural cyclic lighting. They were also similar on the light phase of the 6L/6D regimen and the quasi-natural lighting.

Animals↗