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Specimens of Acrotelsa collaris were confined on representative paper samples and on filter paper impregnated with milk food. Each stadium was divisible into a feeding and a non-feeding period. Stadial and feeding durations (42 ± 1 and 29 ± 1 days) were not statistically different on the untreated papers except one. On the milk food paper stadial and feeding durations were significantly shorter (27 ± 2 and 18 ± 2 days). However non-feeding periods were not significantly different (12·0 ± 0·5 days). The total amounts of the different papers ingested in a single feeding period were similar. Art and milk food paper were eaten faster. The approximate digestibility values were in the range 63–77 per cent. There was a general loss in body weight, except on milk food paper that was replaced periodically.

SUMMARY Goats were milked hourly for 51 consecutive hours or at 13-hour intervals for 32 consecutive milkings. Milk production, milk fat percentage, somatic cell content, and milk serum proteins were considered as a function of time of day and infection. Milk production and milk constituents were not time-of-day dependent. Infection significantly reduced the milk produced, and increased the fat percentage and somatic cell content. Milk production and cell concentration were inversely related. Hourly milking resulted in a linear increase in milk of 0.57 ml./hour. Cell concentration decreased in a curvilinear manner. When milked at 13-hour intervals, fat percentage decreased linearly at the rate of 0.16 per cent per milking. Percentages of albumin and immuno-G-globulins increased and a-lactalbumin, b-lactoglobulin decreased in milk from infected glands. The lack of diurnal variation in milk cell content is probably explained by the facilitation of cell passage within the mammary gland by oxytocin.

SUMMARY An experiment is described in which 28 lambs reared under worm-free conditions were fed on a low cobalt diet. When the lambs were approximately nine months of age they were randomly divided into four groups, two of which were supplemented with cobalt. Four weeks later the lambs of one supplemented and of one non-supplemented group were given 70,000 H. contortus infective larvae. Though there was no growth response to cobalt administration, liver cobalt levels of non-supplemented lambs were in the range associated with cobalt deficiency. In the early stages of infestation, cobalt-supplemented lambs showed higher egg counts, more severe anaemia and a 43 per cent mortality compared with lambs whose low cobalt diet was not supplemented and in which there was no mortality. It is concluded that a low level of cobalt in the diet of the host is detrimental to H. contortus.

SUMMARY Two experiments with lambs reared under worm-free conditions and fed on low cobalt diets are described. In the first experiment, a group of cobalt-supplemented lambs harbouring a worm burden consisting of Ostertagia circumcincta superimposed on a long-standing Trichostrongylus axei infestation had significantly lower serum vitamin B 12 levels than cobalt-supplemented lambs some of which were worm-free while others harboured only a recently-acquired O . circumcincta infestation. In the second experiment lambs which were infected with O . circumcincta , and in which cobalt deficiency was kept at a subclinical level, showed higher egg counts, lower haemoglobin concentrations and poorer weight gains than similarly infected lambs receiving adequate cobalt. The results indicated that the effects of low cobalt intake and a mild to moderate O . circumcincta infestation were additive.

Eggs of Trichosomoides crassicauda were collected from rat urine on filter paper and placed in capsules covered with Millipore filter paper. When the capsules were fed to rats and either recovered from the feces or removed surgically from the large or small bowel, the eggs were hatched; but if removed while still in the stomach no hatching occurred. Hatching took place within the capsules when they were inserted directly into the small bowel (unless the bile duct was tied off), and when they were in a balloon connected to the small bowel; but no hatching occurred when the capsules were placed free in the peritoneal cavity or in a balloon connected directly to the bile duct. In vitro hatching within the capsules was produced at 37 °C with 0.1 N sodium bicarbonate and 0.03 N sodium dithionite equilibrated with 10% CO 2 to produce a pH of 7.4. Hatching dropped off with pH changes in either direction, but pH adjustment alone without the dithionite did not produce significant hatching.

1. 1. Levels of glucose, pyruvate and α-ketoglutarate were followed in whole blood of domestic animals (horses, cattle, hogs, sheep, rabbits, dogs and cats) and fowl. 2. 2. Glycaemia was assayed by the o-toluidine method 3. 3. α-Keto acids were determined by the 2,4-dinitrophenylhydrazone method and the single hydrazones were separated by paper-chromatography. 4. 4. Mean blood values for glucose and α-keto acids in individual species were tabulated.

IN A previous paper by Baker et al. (1957) the effects of feeding Nicarbazin to laying hens on the yolk quality of their eggs was described. Neither the nature of the damage to the yolk nor the mechanisms involved in causing the damage were known. Experiments were designed to study the possible mechanisms involved. MATERIALS AND METHODS Eggs were obtained from hens fed Nicarbazin. The scoring system used to estimate yolk damage was the same as described previously (Baker et al., 1957). Water uptake of the yolk was determined according to the method of Orru (1939). The intact yolk was dried on filter paper, placed in a tared beaker and covered with the experimental solution. The system was incubated at 37°C. for 3 hours, the fluid drained off and the last traces of solution removed with filter paper by rolling the yolk over the paper. It proved to be practically . . .

Data obtained from screening newborn babies for elevated blood phenylalanine levels by the widely used technique of using punched discs from blood-soaked filter paper coupled with an automated fluorometric procedure revealed a seasonal variation in “apparent” blood phenylalanine concentrations. The variation was shown to be related to variations in relative humidity. The more humid the surrounding atmosphere the more the blood spreads through the filter paper and the less will be contained in a punched disc. The need in certain instances for a more precise means of quantification is discussed.

The free amino acids in the diapausing egg of Teleogryllus commodus were determined during the course of its development from oviposition to eyespot by means of paper chromatography. A total of twenty amino acids were identified at diapause. Changes in the concentration of amino acids during diapause development at low temperature were compared with those that took place during the termination of diapause by treatment with ammonia. The most noteworthy change occurred in the level of glutamine, which showed a marked rise following both treatments. Exposure to an inefficient temperature for diapause termination, namely 23°C, led to only a small increase in glutamine. The only other amino acid that showed a substantial change during diapause termination was alanine, which gradually decreased in level. The significance of these changes, in relation to the process of termination of diapause, is discussed.

Quantitative paper chromatographic determinations of glycerol content in the haemolymph of adult P. brevicornis have revealed seasonal variations in the concentration of this substance. Mean glycerol concentrations in excess of 22 g% have been measured during winter with the values decreasing to less than 1 g% during spring and summer. Acclimation studies gave similar results. In the artificially warmed winter beetles glycerol content decreased to less than 1 g% within 36 hr at 20°C. Glycerol concentrations were closely correlated with the changing supercooling points and haemolymph freezing points in both the naturally acclimatized and laboratory acclimated specimens. Temperature preferences showed a positive correlation with changes in cold tolerance.

Ergot found growing on couch grass in Delaware and Franklin Counties in the central part of Ohio was found to contain above N. F. X limits in ergotoxine content, and below N. F. X limits in ergonovine content. It was also noted that part of the sample was infested with a small beetle-like insect. The infested portions assayed lower in alkaloid and fat content. Evidence was presented by paper chromatography to show the presence of a number of ergot alkaloids and lysergic acid.

One hundred White Leghorn hens in each of two experiments were divided into two groups based on lysozyme content (negative moving fraction at pH 8.5) of the thick egg white. Paper electrophoresis was used to index 260 pullets for experiment 1 and 100 pullets in experiment 2. Fifty birds producing eggs of the highest and 50 with the lowest lysozyme content were used for egg quality studies in each experiment. Data were obtained on an individual hen basis for interior quality of fresh eggs, in Haugh units (H.U.), quality loss during storage, egg weight, shell quality and percent solids of albumen and yolk. Haugh unit values of fresh eggs were similar for high and low lysozyme eggs in both experiments. Differences in shell quality, egg weight and solids content of albumen were not significantly different in either experiment. Quality losses during storage were significantly different in both experiments. Quality losses during storage were significantly (P Differences in solids content of egg yolks were statistically significant (P

The relationship was studied between length of incubation in a liquid synthetic medium, amount of bacterial growth, pH of the culture filtrate and tuberculin yield of a single strain, DT, of Mycobacterium tuberculosis. No simple relationship was found between the total crop of bacteria and the tuberculoprotein content of the culture filtrate. On the other hand, protein release and the pH of the culture filtrate were closely related. In each of two trials the bacterial crop increased rapidly during the early period of incubation, although maximum growth was not reached until 9 and 13 weeks respectively. In each of two trials the bacterial crop increased rapidly during the early period of 5 weeks incubation and then fell until the 10th week; a second rise occurred until the 13th week when the pH dropped again and levelled off slightly on the alkaline side of neutrality. The rate of increase in tuberculin yield was most rapid during the first 7 weeks of incubation. After this, the rate of increase slowed down but the yield was still rising after 18 weeks. It is concluded that for the large-scale production of mammalian tuberculin by the method used in these trials, it is profitable to incubate production cultures for 14 weeks or longer.

1. 1. Acclimatized specimens of Hydrobia ulvae show a linear increase in oxygen consumption with decreasing salinity. The quantity of amino acid tends to decrease with decreasing salinities. 2. 2. Specimens transferred to different salinities may show a temporary increase in oxygen consumption and α-alanine concentrations. The temporary increase in oxygen consumption appears to be a standard increment. The increase in α-alanine presumably reflects quantity of pyruvate, the respiratory substrate. 3. 3. The linear relationship of oxygen consumption to salinity in acclimatized animals is related to osmoregulation. The temporary, incremental increase in oxygen consumption may be related to the cyclical behavioural activity of the prosobranch mollusc H. ulvae under estuaraine conditions.

AS THE industry moves toward a program of non-storage eggs the year around, methods of preserving the quality of shell eggs during marketing becomes paramount. The use of oil treatment, carbon dioxide atmosphere, thermostabilization or plastic treatment has been suggested by various investigators (Evans and Carver, 1942; Sharp and Stewart, 1931; Funk, 1943; and Yushok and Romanoff, 1949, respectively). However, a direct comparison of the relative efficiency of these methods under varying seasonal and storage conditions has not been made. Flavor is one of the most important factors in consumer acceptability of shell eggs. Few preservation studies, however, have included flavor as a method of evaluation. Mallman and Davidson (1944) and Shenstone and Vickery (1957) reported that oil coatings did not retard the onset of stale flavors during storage. Sauter, Harns, Stadelman and McLaren (1954) found no significant differences in the flavor of fresh eggs produced in the different seasons.…

INTRODUCTION CHLORINATION of an entire poultry processing plant water system at 10, 20 and 45 parts per million chlorine was studied by Drewniak et al. (1954). Twenty parts per million chlorine significantly reduced the bacterial load on chicken carcasses prior to chilling. These results were confirmed by Patterson (1958), who sampled frozen birds produced in a plant using different levels of chlorination in the entire water supply. Without special precaution, however, long-term chlorination at this level can corrode steel, stainless steel, and brass currently used in poultry plant plumbing systems (Mercer and Somers, 1957). This factor makes whole-plant chlorination at 20 parts per million impractical in many areas without installing either deionizing systems to remove minerals and/or pH adjustment using sodium hydroxide. Ranken et al. (1965) and Barnes (1965) indicated that chlorination at 200 parts per million in the slush ice chilling of birds extends shelf-life slightly and reduces the…

This paper is the first of a series on the craniology of four species of Bos . Here (and in the next paper) Bos taurus in Britain is used to establish a basic craniology for the genus. In the initial sections notes are made on the nomenclature, material available, history, and age assessment of B. taurus . The subsequent section deals with the effects of sex, age and breed on absolute size. The results show that Bos taurus is very variable, particularly in the length of the horncore. Sex influences certain dimensions very greatly, particularly those of breadth. Although the horns of cows are often longer than those of bulls of the same breed the horn cores may be shorter in cows. In studying the effects of age it can be seen that growth rates are initially very high, slowing down at about three years of age. Tooth row length decreases with age and hence it is a particularly unreliable indicator of size. Obviously breed affects size and it has been possible to divide the skulls studied into size groups which correspond well with known body weights.

Laboratory mice, Mus musculus, were bred at two environmental temperatures, namely, 21 °C and −3 °C, and aspects of their behaviour observed. Inbred strains, A, A2G, C57BL and GFF were used; F1 mice were produced by crossing the inbred strains; and an outbred stock was derived by crossing all four. General activity was recorded in three inbred strains, F1 mice from two crosses, and outbred mice, during a period of 5 days, in a cage crossed at three points by a beam of light; breaking the beam activated a counter. C57BL mice were more active than A or A2G; the F1 and outbred mice resembled C57BL or were more active still. Cold reduced activity in all the kinds of mice studied. Activity was usually higher on the first than on subsequent days. “Functionless” gnawing was studied over a period of 7 days (a) by weighing the amount of cubed diet gnawed and wasted, (b) by supplying balsa wood and recording the amount chewed off. The mice were (i) solitary or (ii) in groups of 3. At 21 °C, of the four inbred strains, A2G gnawed most, C57BL rather little. F1 mice (from 7 crosses) usually wasted more food, and always (8 crosses) gnawed more balsa wood, than their parent strains. Outbred mice, when alone, gnawed more balsa wood than inbred strains and more than most F1 types. All kinds of mice gnawed less, when kept in groups, than when alone. No functionless gnawing was observed at −3 °C in any class of mice. “Nest-building” was studied by hanging 24 paper strips over the side of the cage. In simple nest-building there was no nest already present; in double nest-building there was already a nest of cotton wool. All inbred mice were slow to pull down the paper strips; all F1 mice from 10 crosses, and the outbred mice, were quick to respond to them. The rate of response tended to be higher in double nest-building. F1 and outbred mice tended to make better nests, of cotton wool and paper combined, than inbred mice. At −3 °C the response to the paper strips was usually slower than at 21 °C; and the final nests in the cold were, on the whole, no better than in the warm. If “general drive” is defined in terms of output of mechanical energy, then low temperature reduced general drive in these experiments; heterozygosis may have increased it; heterozygosis certainly increased speed of response to new conditions.

Seven virgin female mice of strain RAP (albino) were trained to key-press, using paper as a reinforcer. Their behaviour was recorded when paper was delivered non-contingently, and when it was contingent upon key-pressing on CRF and FR schedules. When the contingency was introduced, the number of pieces of paper taken decreased. As fixed ratio size was increased, the overall response rate remained constant, and the reinforcement rate declined. The sequence of nest-building activities which accompanied delivery of paper was also observed to change as a function of schedule.

This paper is the second of a series reported from the Utah Station on the transfer of dietary DDT to eggs and poultry tissues. The first paper was reported by Bryson et al. (1950) on the accumulation of DDT in poultry products. The published literature on this topic has been reviewed and reported by Bryson et al. (1950). EXPERIMENTAL THE alfalfa hay fed in this experiment was from the same field described by Harris et al. (1949). This alfalfa was dusted with 0, 1, 2, and 4 pounds of technical DDT per acre. The harvested hay was ground into meal and 15 percent of this meal was included in the laying mash. DDT was also added to a similar mash made from untreated alfalfa meal at levels of 0, 50, 100, and 200 p.p.m. These diets are reported in Table 1. The design of this experiment is as follows: A . . .

It was predicted in previous papers of this series that adult females with no apparent skin lesions might show appreciable day to day variations in the pH of the skin surface. If such variations do exist, it then becomes important to make numerous determinations on single individuals before comparing one with the other. Five adult females, ages 20 to 25 with no apparent skin lesions, were chosen and pH determinations on six areas of each arm were made as nearly daily as possible over a six months period. The time did not run consecutively in all cases, but in general extended from late summer to early spring. Each individual was measured approximately 120 times. The technique for making the measurements was described in the first paper (1) of this series. In measuring these five individuals it was found that some were more constant than others. In figure 1, there are shown the variations which occurred in the pH readings on the extensor surface of the upper arm for the two individuals who showed the maximum and the minimum daily changes. Note that in one the range is from 4.58 to 6.85 with a maximum change within a 24-hour interval of nearly two units. In the second individual, the range is from 5.00 to 6.12 with a maximum 24-hour change of only about 0.5 units.

I. Introduction The purpose of this paper, which is one of a series on the various problems of the biology and economics of egg production in the domestic fowl, is a presentation of constants showing the relationship between monthly egg production aud annual egg record in the pullet year in the White Wyandotte breed. From the purely biological side the present paper is a contribution of detail to the quantitative measurement of the interrelationship of the variables which must be considered in any comprehensive study of the broad problem of the physiology of egg production. The specific purposes of the determination of the various coefficients have been fully enough stated in preceding papers,* and will not be reiterated here. A comparative discussion of these correlations for the economically more important breeds of fowl is in preparation; the constants here presented will then be discussed in greater detail. In the meantime, . . .

A SURVEY of the literature on the vitamin A requirements of the growing chick revealed that at least eight papers on this subject have appeared since 1926. (Almquist and Meechi, 1939; Bearse and Miller, 1937; Biely and Chalmers, 1936; Record, et al. 1937; Ringrose and Norris, 1936; Sherwood and Fraps, 1936; Tepper and Durgin, 1938; Wilson, et al. 1936). These papers were examined with the following criteria in mind: (1) Practicality of the ration used, (2) Nutritional adequacy of the ration, except for vitamin A, (3) The number of birds per test group, (4) The attainment of what might be considered normal weight at 8 weeks of age, (5) The presence of a group whose growth response is less than normal, (6) The use of a practical source of vitamin A or carotene, and (7) relatively small differences between levels of vitamin A. None of the experiments noted met all . . .

IN THE first paper of this series (Lorenz and Starr, 1952; referred to hereafter as 1) the results of a study of washing eggs by different methods in the laboratory were discussed and pertinent literature was reviewed. The experiment reported here was intended to obtain more extensive information on some of the variables discussed in that paper and to compare washing in the laboratory with washing on the ranch. MATERIALS AND METHODS Eggs from a single nearby poultry ranch only were used in this trial. Three days each week during 4 consecutive weeks the entire day’s production of this ranch was brought to the laboratory immediately after the final collection for that day. These eggs were then segregated at once according to cleanliness, and eggs that had checked or grossly imperfect shells were removed. The sound shelled eggs were then cleaned at once, except for two instances in which washing . . .

This paper supplements a previous article on the same subject which appeared in P oultry S cience , Vol. 6, No. 3. In the former article the data was secured from fourteen White Leghorn hens. The material in this paper was obtained from thirteen Rhode Island Red hens. The experiment was conducted in the same manner as the one previously reported, except that the period over which the hens were trapnested and eggs were examined was of two month’s duration instead of three. The White Leghorn hens used in the other experiment were obtained from a flock in-which practically no, or at least very slight, losses from bacillary white diarrhea were said to have occurred during the past two or three years. On the other hand, the Rhode Island Red hens employed in this experiment came from a flock in which rather heavy losses occurred during the previous spring. The owner of . . .

THE work described in this paper was undertaken in an attempt to obtain further information on comparative physical, chemical and cooking qualities of eggs stored by five different methods of preservation that could be easily duplicated in the home. Methods chosen for study were waterglass, freezing, application of a commercial creamy emulsion, oiling, and coating with a plastic. The eggs were tested at the end of three and six months’ storage. EXPERIMENTAL METHODS Clean, grade AA eggs from New Hampshire hens were delivered daily from the college poultry farm to the laboratory during a three-week period. All eggs except those to be frozen were dated, numbered, weighed and marked with their individual fresh weights. The eggs treated by means of commercial creamy emulsion, oiling and plastic coating were packed, small end down, in paper egg cartons. All eggs were stored in the dark at 50 to 60°F. and at a . . .

THE preceding papers in this series by Cuckler et al. (1956) and Cuckler and Malanga (1956) showed that nithiazide [1-ethyl-3-(5-nitro-2-thiazolyl) urea] was the most effective antihistomonad (blackhead) agent in a series of closely related compounds. Furthermore, nithiazide was found more potent and less toxic than 2-amino-5-nitrothiazole in experimental enterohepatitis. This paper presents the results of studies on the absorption and excretion of nithiazide by turkeys and chickens and the effect of this compound on their growth, maturation and reproduction. These studies have shown that chickens and turkeys tolerated nithiazide better than 2-amino-5-nitrothiazole or 2-acetylamino-5-nitrothiazole, chemically related compounds. MATERIALS AND METHODS The turkeys and chickens used in these studies were obtained from commercial sources when 1 day of age. Straight run Beltsville White turkeys and White Rock cross chicks were used in the laboratory experiments, and the birds were kept in electrically heated battery brooders. The floor-pen growth trials involved White . . .

INTRODUCTION SELECTION is considered to be the best tool for genetic improvement in a given population. Heritability of a character is an important factor affecting genetic improvement. In a previous paper, Issawi et al. (1963) studied heritability of fertility and hatchability in Fayoumi. The present paper deals with the study of heritability of body weight in Fayoumi. REVIEW OF LITERATURE Many investigators estimated heritability of body weight in chickens. Spector (1956) summarized the different estimates of this character and concluded that it was highly heritable. In Single Comb White Leghorn, Lerner et al. (1949) stated that heritability of body weight at twelve weeks of age was 0.475, and 0.597 and 0.506 on the basis of the contribution of sire, dam, and both, respectively. Fagan (1949), reported similar figures for heritability of body weight at twelve weeks of age, being in the range from 0.35–0.50. El-Ibiary and Shaffner (1951), reported…

Strictly aerobic metabolism in Iguana iguana during walking was highly temperature-dependent, as was the maximum rate of walking without the incurrence of an oxygen debt. The absolute maximum rate of walking aerobically correlated with the temperature of the maximum metabolic scope. 2. The energetic cost of walking did not increase with temperature, but rose curvilinearly with speed, the efficiency being greatest at the higher rates of walking. 3. Diving iguanas could remain submerged for up to 4½ hr, tolerating blood lactate levels as high as 320 mg per cent. THIS paper will deal with the study of metabolism and its side-effects in iguanas actually engaged in types of activity to be expected in nature. The two activities considered are diving and walking. Both had to be studied under artificial condi- tions because of the nature of the parameters being measured, but it is believed that the data obtained are relevant to natural situations. Walking at a measured rate is of particular interest because it is an activity regularly undertaken in the field by iguanas. It is also convenient to study as the duration and severity of the exercise are easy to regulate. According to Fry's (1947) hypothesis, discussed in the previous paper (Moberly, 1968), the temperature where the metabolic scope is greatest should correspond with the temperature where that animal can sustain the highest rate of movement for the longest length of time. In the iguana this should occur at about 32°C (Moberly, 1968). Other parameters of interest can also be observed in walking experiments. These involve the relative efficiencies of muscular exercise at varying speeds and temperatures. For instance, man's efficiency in running increases up to a point as the rate increases, after which it begins to decrease (Karpovich, 1965). In sock-eye salmon (Oncorhynchus nerka), the efficiency of swimming shows much the same sort of phenomenon. An addi- tional consideration is applicable to poikilotherms. In sock-eye salmon, the cost of

This paper is a preliminary report on some results obtained in attempting to estimate the gross maintenance requirement of White Leghorn chickens from data obtained from feeding experiments specially planned for that purpose. The expression, “gross maintenance requirement,” as employed here, is used to designate that weight of feed (in grams) which a chicken requires each day for all purposes, except for increasing its live weight and for producing eggs. The feeding experiments were so planned that a number of pens of chickens were fed at levels of feed intake which differed from one another by a fixed amount, all the levels of feed intake being less than that required for maintaining live weight. The daily allowance of feed for each pen was weighed and placed in small paper bags before the experiment was started, and each morning during the experiment proper one of these bags was emptied into the . . .

IN A previous paper (Shao and Hill, 1968) it was reported that thiouracil as a dietary supplement reduced the concentration of free lysine, threonine, tryptophan, methionine and leucine in the blood plasma of chicks. The present paper gives the results of experiments in which thiouracil and/or iodinated casein were added to a basal diet and extends the observations to several additional amino acids. EXPERIMENTAL The basal diet, essentially a wheat, corn soybean meal mixture, was described in detail by Shao and Hill (1968). White Plymouth Rock pullets were fed this diet from day old to 7 days of age and then divided on the basis of weight into lots of 12 chicks each. The experimental diets were assigned to these lots at random, each diet to 4 lots and the experiments continued for another 14 to 15 days. Blood samples were removed from each chick in two lots per treatment…

THIS paper presents an analysis of a set of feather measurements obtained at the Beltsville Research Center during the course of an experiment designed to determine the effects of certain mineral supplements, particularly inorganic sulphur compounds, on the molt of White Leghorn hens. Since the molt is usually accompanied by a cessation of egg production, the importance of favorably influencing the growth of feathers, if it is possible to do so, is obvious. In view of the fact that feathers contain considerable amounts of sulphur, it was thought that the feeding of sulphur compounds might have some effect on the rate of growth and mature length of the new tail and wing feathers which were grown after the old feathers were dropped during the molt. The general plan of this experiment, including a description of the sulphur compounds fed, has been given in an earlier paper (Hendricks, 1933). Three groups . . .

SEASONAL variation in the rate of egg production is associated with seasonal variation in length of day. The excellent paper of Whetham (1933) summarized a very large amount of data from a wide range of latitudes, all showing correlated changes in day length and rate of egg production. Kennard and Chamberlin (1931) showed that seasonal variation can be modified by use of supplementary artificial light, confirming the work of several earlier laboratory workers and of many poultrymen. Kennard and Chamberlin also showed the close relationship of body weight and rate of egg production. A good review of the earlier literature is contained in the paper of Callenbach, Nicholas and Murphy (1944). Several analyses of egg production data for the purpose of describing the relation of time in production and rate of production have been made. Harris et al. (1921) reported that annual production within a genetically similar flock maintained under . . .

Individuals participating in the Tecumseh Community Health Study, in 1959–1960 (TCHS I) and 1962–1965 (TCHS II), had serum uric acid determinations by an enzymatic spectrophotometric method, SUA(ES), as part of a comprehensive health examination. Among the 1633 male and 1725 female subjects, the mean serum uric acid concentration had increased by 0.32 mg per 100 ml for males, and by 0.18 for females, over the the average of 4.1 yr between determinations. It was found that, approximately, 40 per cent of subjects had a decrease, and 56 per cent, an increase, in serum uric acid concentration. The change was greater than plus or minus 2.0 mg per 100 ml for 28.7 per cent of males and 19.4 per cent of females. Decreases of as much as 8.2, and increases of as much as 9.9 mg per 100 ml were observed. How much of the average increase, in an average 4.1 yr interval between tests, is due to ageing, except for males in the age range of 10–19 yr, is problematical. It seems probably that most of the average increase was due to technical factors in performance of the test. In the study of 1962–1965, serum uric acid determinations were done by two methods. An automated colorimetric method was compared with an enzymatic spectrophotometric method. Both methods showed the same types of distribution curves of serum uric acid concentrations and curves of age-sex specific mean serum uric acid. The values obtained by the automated colorimetric method were slightly, but, consistently, higher to a statistically significant degree than those of the enzymatic spectro-photometric method. For 2092 male subjects, the mean SUA(AC) was 0.21 mg per 100 ml greater than the mean SUA(ES), while for 2104 females subjects, this difference was 0.14. Of 4196 study subjects, whose sera were tested by both methods, about 90.0 per cent showed an agreement of the two values within ± 0.9 mg per 100 ml. However, 1.9 per cent of males and 1.6 per cent of females, had ES values which exceeded AC values by 2.0 mg per 100 ml, while 2.8 per cent of male and 2.3 per cent of female subjects had AC values greater than ES values by 2.0 mg per 100 ml. The extremes of differences range from 4.4 to 7.3 mg per 100 ml. The data in this paper gives us increased confidence in the essential validity of the mean age and sex distributions of serum uric acid values, from the Tecumseh Community Health Studies, published in an earlier paper [2]. It is concluded that, for the purposes of population studies, the automated colorimetric method is more advantageous than the enzymatic spectrophotometric method, because of its lesser cost. Comparison of the results of the two studies emphasizes the problems of definition of hyperuricemia. Further mathematical analysis of the distribution curves obtained in such studies may lead to definitions of normo- and hyperuricemia of greater precision for clinical purposes.

WORK leading to the development of a ration for the uniform production of perosis (slipped tendon) in chicks was presented in the previous paper. In this paper we wish to give the results obtained from studies on factors which prevent the development of this syndrome. Jukes (1937) has recently reviewed the meager work available on the perosis-preventing properties of certain feeds. EXPERIMENTAL Day-old White Leghorn chicks were divided into groups of five chicks each and placed in suitable cages. In the majority of the work ration 604 was used as the basal ration, but results obtained with other closely related rations are also included. The supplements tested were added at the expense of the whole ration. The results are tabulated in Table 1. It is readily evident that the addition of 15 percent of rice bran gave complete protection in all trials. The result checks quite well with the conclusion . . .

THE first of the experiments discussed in this paper was started soon after the discovery that one of the commercial vitamin B12 supplements contained an unknown factor that stimulated the growth of young chickens (Stokstad et al., 1949). After it was found that the factor was an antibiotic (Stokstad and Jukes, 1950), the second experiment was conducted to determine whether the inclusion of an antibiotic in their diet during hot weather would stimulate the growth of young White Leghorn pullets fed a diet containing cottonseed meal as the chief source of protein. Because the stimulation of growth in the second experiment was relatively small in comparison with some of the results that were attributed to the antibiotics, it was considered advisable to conduct other experiments during cool weather. The data from the four experiments at the Southwest Poultry Experiment Station, Glendale, Arizona, are given and discussed in this paper. PROCEDURE . . .

IT IS common experience that chickens and other domesticated birds grow better if hatched at certain seasons than they do if hatched at other seasons of the year. Thus Goodale (1926) found that chicks hatched in the early part of the season grew more rapidly, to 30 days of age, than did those hatched later. Upp and Thompson (1927) likewise observed that there were differences in the rate of growth of chicks hatched at different seasons of the year. They conclude that weather has an influence on the growth of chickens. Somewhat similar results are reported in this paper for turkeys hatched only a few weeks apart. There is also a distinct indication of compensatory growth of the later hatched, initially slower growing birds. The same phenomenon has been demonstrated in the growth of razor clams by McMillin and Weymouth (1935). MATERIALS AND METHODS The data presented in this paper . . .

Rubin, Bird, and Rothchild (1946) reported that hen feces contained a factor essential for maximum growth of chicks fed a cereal grain-soybean oil meal diet containing adequate amounts of the known growth factors. The discussion in the paper by Rubin et al. (1946) indicates that these workers believed the chick growth factor was synthesized in the intestinal tract of the hen. However, it was pointed out that the possibility of synthesis after voiding of the feces could not be ruled out. Since no description of the manner of collecting the feces or the time and temperature of holding before drying was given in the paper by Rubin et al. (1946) it was considered desirable for us to determine whether fecal material reduced to temperatures too low for bacterial growth immediately after voiding would contain chick growth promoting properties. Feces were collected from White Leghorn hens kept in an unheated house . . .

Ah&met--1. Metabolic rate (cm3 Odhr and log cm3 Odhr) of Vivipaw con~ec~oide~ is dependent on weight and log weight at levels of minimum and intermediate activity in males and minimum activity in females. 2. Weight specific oxygen consumption and log weight specific oxygen consumption of I’. contectoides is dependent on weight and log weight at levels of intermediate and maximum activity in males and at all activity levels in females. 3. Respiration coefficients are affected by activity level or time of day. They decrease significantly with increasing activity level in males. Respiration coefficients are generally lower than literature values. 4. The relationship of oxygen consumption to weight is similar for males and females at each level of activity. 5. Mean absolute oxygen consumption (cma/hr) is greater for females than males at each activity level. Mean weight of females is greater than mean weight of males. fN”IXODUCIION METABOLIC rates of animals are influenced by many factors, including ambient temperature, time of day, time of year, sex, age, level of activity, weight, etc. Additionally, oxygen consumption of aquatic invertebrates may be influenced by pH, osmotic pressure, dissolved oxygen availability. substrate composition, etc. This is the tirst in a series of papers dealing with the effects or relationships of most of the above parameters to bioenergetics of a prosobranch snail, Viviparus confecfoides.

This paper describes a simple test system for studying the ability of ewes and lambs to recognize each other, and for elucidating the senses involved in the recognition. The system consists of an enclosure into which the ewe and lamb are simultaneously released from opposite ends, and the degree of interest each displays in the other is rated. The results are presented from tests on Clun Forest, Finnish Landrace, Jacob and Soay ewes and lambs, sheep with a wide range of coat colour and colour pattern. Discrimination, by both ewes and lambs was made more readily when the test partner was of dissimilar colour or colour pattern to the natural partner, and this difference tended to persist even when the alien partner was of the same breed as the natural partner. The results suggest that mutual recognition of ewes and lambs is to some extent based on vision. Contrary to expectation, a high proportion of lambs of these breeds recognized ewes as aliens even on the first day of life. When the aliens were dissimilar in appearance to the lamb's own mother the ability to discriminate clearly improved with age. The ewe's ability to discriminate did not improve as the time since parturition increased, but ewes tended to be more interested in young lambs than in lambs 1–3 weeks old.

This paper describes the standard practices developed and repeated successfully to induce spawning annually under controlled conditions. The method for sampling ova in vivo and the stages of egg development are described and illustrated. Hypophysation of the gravid females begins when intraovarian oocytes are at the tertiary yolk globule stage. For best results mean egg diameter is at least 600 μ, and preferably larger than 650 μ before inducement begins. For small and less-developed eggs, hypophysation can be induced by varying the dosage and the injection sequence as outlined. Partially purified salmon gonadotropin required to induce spawning is given in two injections, one-third of the total dose is given initially followed by the remaining two–thirds 48 h later. The total dose is inversely proportional to the initial egg diameter of recipient females and varies between 12–21 μg/g body weight. An illustrated diagram for calculating dose level is provide. Fertilization procedures are also described.

This paper outlines the major principles involved in beef production from grassland. It reviews the major management systems and discusses the factors influencing the variations in efficiency and profitability. The data and conclusions are largely based on information collected by the British Meat and Livestock Commission. The main aspects are: 1. (1) High concentrate prices are forcing farmers to use grass more efficiently. 2. (2) Beef systems can utilise a wide range of grassland types. In particular beef cows can use poor pastures in difficult environments. 3. (3) A brief outline of the United Kingdom beef industry is given together with detailed descriptions of different production systems. The choice of system should depend on the available physical and financial resources. 4. (4) These systems are based on target levels of performance, they are not rigid but may be adapted to suit individual farm situations. 5. (5) Within a single system there is a wide range is performance and profitability and a direct relationship between daily liveweight gain and gross margin per animal. It is important to obtain maximum gains during the grazing season. 6. (6) There is a wide variation in the effective use of grass. In practice there is no relationship between the use of nitrogen and output per hectare, nor between stocking rate and daily gain per animal. There is a strong relationship between stocking rate and gross margin per hectare. 7. (7) As more grass and less concentrates are used the growth rate decreases and the slaughter weight increases. Producers with the best financial results within a system use less feed but achieve better liveweight gains.

A total of 1127 breeding soundness examinations was conducted on 1005 bulls utilizing the method of examination and criteria for classifying bulls of the Society for Theriogenology. Classification of bulls according to breeding soundness potentials was as follows: 83.5% of the bulls were satisfactory, 9.0% of the bulls were questionable, 6.9% of the bulls were unsatisfactory and .6% of the bulls could not be classified. There were no breed differences in classifications. After 60 months of age there was a greater incidence of unsatisfactory potential breeders. Of the 178 questionable and unsatisfactory bulls, 54 were re-evaluated after a rest period of approximately 72 days. Questionable and unsatisfactory bulls less than two years of age improved to satisfactory status on subsequent examinations more often than bulls greater than 2 years of age (P Breeding stock has for years been selected on the basis of conformation, carcass quality, rate of gain, feed conversion, mothering ability, and color markings. Many producers are now including breeding soundness examinations as a basis for selecting breeding animals. Although there have been many papers published describing various methods of clinically determining breeding potential in bulls, there are only a few reports summarizing the results when any of the described methods have been applied to large numbers of bulls. The University of Missouri Veterinary Clinic has been one of the major collection centers in the State of Missouri for conducting breeding soundness examinations for a number of years due to its central location and close proximity to many of the state-tested bull sales. A summary of 1127 breeding soundness examinations is being reported.

Preliminary techniques of mass propagation of grey mullet were established in Taiwan some years ago. Among the many problems concerned, the cryogenic preservation of grey mullet sperm has been studied since 1971. The aim of this study is not only to ensure the availability of mullet semen anywhere and anytime it is needed, but also to contribute to the international cooperation of cross breeding of grey mullet in the future. Results of the study on cryogenic preservation of grey mullet sperm made during the experimental mass propagation of mullet in the Tungkang Marine Laboratory for the past 3 years are summarized in this paper. The gonadosomatic index (GSI) of male grey mullet migrating near the coast of Tungkang ranged from 4 to 20 during the spawning season. The pH value of the semen was 7.4. Each spermatozoon was composed of a head part measuring 2.3 μ × 1.4 μ and a tail part four to five times as long as the head. There were about 5.3 × 1010 sperms in each ml of semen. Eosin-nigrosin staining was used for clearer identification. Sperm motility was preserved for up to 23 days in the case of raw semen at 5° C. Cryoprotective agents were needed at the ultra-low temperature (−196° C) of preservation in liquid nitrogen. Feasible procedures of freezing the grey mullet sperm were determined. Fresh semen diluted with cryoprotective agents was dispensed into 0.5 ml straws which were then sealed. These pretreatments prior to cryopreservation had to be done within the correct equilibration time of 1 h or less. Semen in straws was precooled in liquid nitrogen vapor until a temperature of −80° C was reached. Straws in the canister were then put into liquid nitrogen for long-term preservation. The optimum effect of cryoprotective agents was found with 5–10% glycerine or dimethylsulfoxide (DMSO) at 1:1, 1:5, and 1:10 dilutions. In this condition, both good motility and fertility before freezing and cryoprotection were obtained. So far the best result of frozen thawed mullet sperm was moderate motility and 2.7% fertility of the semen cryopreserved for 1 year and 4 days.

This paper describes experiments in which nine species of prawns were compared for their suitability for intensive culture in closed systems. The species tested were: Macrobrachium rosenbergii, Penaeus aztecus, P. indicus, P. japonicus, P. monodon, P. occidentalis, P. orientalis, P. schmitti and P. setiferus. Tanks with a bottom area of 0.6 m2 and water depth 20 cm were stocked with juvenile prawns (0.2–0.5 g mean live-weight) of each species at two stocking densities, equivalent to 25 and 166 prawns/m2. Water conditions were maintained at 28±2°C and 28–30‰ (M. rosenbergii was reared in fresh water), and growth and survival were monitored during 16 weeks. Fastest growth was recorded for P. monodon and P. orientalis, which reached mean live-weights of 25.43 g and 22.80 g respectively at the low stocking density and 12.95 g and 14.63 g at the high stocking density. Best survival was recorded for P. monodon, which was considerably better than any of the other species. It was concluded that P. monodon and P. orientalis merit further consideration as candidates for intensive culture.

A suction trap was run continuously in a Nigerian store containing cowpeas in order to capture flying adults of Callosobruchus maculatus . Of the 211 adults caught, 149 were females and 133 of these were of the active form. Adults were also removed from in all, 8 kg of cowpeas sampled on four occasions from the store and in these only one-third of the adults were active females. The numbers of adults caught by the traps were recorded hourly and from these records, using probability paper, two peaks of flight activity were detected, a small one with a mean at 07·20 hr ± 260 min and the main one at 17·50 hr ± 110 min. The beetles flew throughout the day and night with no inhibition by low light intensity. Temperature appears to be the most important factor and peak flight activity occurred at highest temperatures and low relative humidity. The first small peak activity in the morning was ascribed to the rise in temperature above the low ambient night temperatures which are probably lower than the threshold for the species.