Pound Of Feed Research Articles

Oxytetracycline residues in a freshwater recirculating system

When oxytetracycline (OTC) medicated feed is fed to fish in a recirculating aquaculture system, antibiotic residues could accumulate in fish tissue, water, biofilter sand and sediment to a greater extent than in single pass or serial reuse aquaculture systems. In two trials, oxytetracycline-medicated feed (3 g active ingredient per pound of feed) was fed to adult rainbow trout at 1% b.w. per day for 10 days. OTC residues were assayed in fish muscle (with skin attached), water, sediment (e.g., fish feces, uneaten feed) and biofilter sand. For both trials, oxytetracycline was detected during the 10 days of treatment in all matrices assayed. In trout muscle, OTC concentrations increased to an average of 1.8 μg/g by day 10 of treatment and then declined to <0.2 μg/g by 21 days post-treatment. For water entering and exiting the biofilter, OTC concentrations increased to 0.5 μg/ml by day 10 and was not detectable (<0.001 μg/ml) by 21 days post-treatment. For biofilter sand, OTC concentration was approximately 14 μg/g by day 10 and decreased to <2 μg/g by 21 days post-treatment. In sediment samples, OTC concentrations increased to 1900 μg/g by day 10 and declined to <2 μg/g by 21 days post-treatment. In this system, OTC concentrations in trout muscle were well below 2 μg/g by 21 days after withdrawal of the drug. After input of medicated feed to the system was stopped, OTC concentrations in water, sediment and the biofilter declined and did not increase during the post-treatment period.

Impacts of Technology and Structural Change on Agricultural Economy, Rural Communities, and the Environment

Recent advances in biotechnology and information technology could revolutionalize U.S. agriculture. Through embryo transfers, gene insertion, growth hormones, and other genetic engineering techniques, cattle, swine, sheep, and poultry in the year 2000 would produce more meat per pound of feed, dairy cows would produce more milk per cow, major crops would be genetically altered to resist insects and diseases and to produce their own fertilizers and herbicides, and computers and electronics would be widely used on farms to increase management efficiency. These are only a few of more than 150 emerging technologies in 28 areas forecasted in an ongoing study by the Office of Technology Assessment (OTA). These areas of technologies range from plant and animal genetic engineering, plant growth regulators, and animal reproduction, to monitoring and controlling technology and telecommunication. Many of these technologies, such as growth hormones, monoclonal antibodies, super ovulation, embryo transfers, and slow-release insecticides are already in the marketplace, while others are still in the laboratory. When these technologies are adopted by farmers and put into the agricultural production system, they could alter drastically the structure of U.S. agriculture, which has been evolving toward a dual structure, where a few large and very large farms produce most of the total output and capture the majority of net farm income while very many small subsistence and part-time farms produce a small portion of the total'output and receive a very small share of net farm income. (For a more detailed discussion of the movement toward a dual structure, see chap. 4 of the OTA report.) Commercialization of new technologies would further stimulate expansion of farm size and accelerate resource concentration in agriculture for two reasons: (a) the biasness of technology adoption and (b) the downward slope of the average cost curve. Although most of the new technologies are scale neutral, i.e., they are equally applicable to large as well as small farms, their adoption tends to favor large farms. Typically, new technologies are first adopted by large farms because these farms have more access to information and

Methods for improving cereal protein quality.

Three methods for improving cereal protein quality are discussed. Two older methods are supplementation with limiting essential amino acids and with protein concentrates high in those amino acids. The most recent method (since 1964) is the replacement of the normal cereal grain with its high lysine mutant counterpart. Three high lysine cereals are now available, corn, barley, and sorghum. In animal feeding, least cost formulas will determine which of the three improvement methods will be used. In human nutrition, cost, availability, palatability and acceptance are all equally important factors. In animals, pounds of gain per pound of feed will be the final measure of cereal protein quality. In humans, especially preschool children, the most important criterion will be the ability of the improved cereal protein to build a strong immune defense system. Animal studies show that protein quality is more important than calories when calories are restricted to less than ad libitum consumption. It is therefore essential that children restricted in their total energy intake have the best cereal protein quality possible to protect their immune system.

Aortic ruptures in turkeys induced by diethylstilbestrol and dienestrol diacetate.

SummaryHigh levels of dienestrol dia-cetate in the feed of turkeys (512, 526, 1024 mg/lb) caused aortic ruptures and decreased weight gains, while a low level (256 mg/lb of feed) caused no mortality and increased weight gains. Comparable mortality, hyper-lipemia, hypercholesterolemia, and hypotension resulted from the feeding of 16 gm diethylstilbestrol/100 lb and 512 or 1024 mg dienestrol diacetate per pound of feed.

The Effects of B-Vitamin Deficiencies on the Efficiency of Metabolizable Energy and Protein Utilization ,

McClureet al. (1934) were apparently the first workers to investigate the effect of thiamine deficiency on the efficiency of energy metabolism. Working with rats, these investigators reported that a vitamin B supplement added to a vitamin B deficient diet had no effect on improving the efficiency of metabolizable energy (ME) utilization. In contrast, Voris (1937) showed that the efficiency of ME utilization decreased by about 12 percent when rats were thiamine deficient.More recently Sibbald et al. (1961) reported data in which four levels of pantothenic acid, 5.6, 6.8, 14.8 and 28.8 mg. per pound of feed, were fed to chicks. The three lower levels had no effect upon energy metabolism whereas the highest level depressed the efficiency of ME utilization. Sibbald et al. (1962) reported on the effects of riboflavin, niacin, vitamin B12 and methionine as related to the efficiency of ME utilization. The basal diet used in …

Feed Pigments: 1. The Japanese Quail as an Assay Animal for Feed Pigments

CURRENTLY two methods are available for measuring the color deposited in poultry or poultry products from feed pigments. The chick assay measures the pigmentation in the shanks, and the hen assay measures the pigmentation in the yolks of eggs. The chick assay is the least desirable of the two for screening purposes since fat-soluble pigments exist that are not deposited in the skin but will color egg yolks (Fritz et al., 1958). A more desirable assay would depend upon the deposition of color in egg yolks, thereby reducing the possibility of missing an effective pigment intended for this purpose. The hen also appears to be a more sensitive assay animal than the chick. Fritz et al. (1958) found that at least 25 mg. of xanthophyll per pound of feed was required to obtain a dark colored egg yolk, whereas only 10 mg. was needed to give normal pigmentation in broilers… .

Studies on the Vitamin D3 Requirement of the Broiler Chick

THE vitamin D3 requirement of the growing chick has been estimated by the National Research Council (1960) to be 90 I.C.U. per pound of feed. Recent studies by Waldroup et al. (1963b) indicated that dietary vitamin D3 levels of 360 I.C.U. per pound increased body weight and percent bone ash. However, the response to higher levels of this vitamin became less as calcium and phosphorus levels approached optimum. To gain additional information regarding the effect of increased vitamin D3 levels and the relationship of this vitamin to the calcuim and phosphorus content of the diet, three experiments were conducted under conditions of practical-type rearing as well as in battery brooders isolated from sources of ultraviolet light. MATERIALS AND METHODSBattery brooder studies—A factorial arrangement with two calcium levels (0.50 and 1.00 percent), two phosphorus levels (0.50 and 0.70 percent total phosphorus) and seven levels of vitamin D3 was used.…

Effect of Body Size and Dietary Energy on the Protein Requirement of Turkey Breeders

CONSIDERABLE research has been directed toward a more basic understanding of the dietary protein and energy requirements and interrelationships in meat type and egg production strains of chickens. However, little direct information is available on the protein requirement of turkey breeders for maximum productive and reproductive performance in relation to dietary energy density, environmental temperature, genetic differences in body size and productive ability.A brief report by Carter et al. (1957a) in which 16 and 18% protein diets were compared indicated that the 18% protein level fed to large type white turkey females at 800, 900 and 1000 Calories of productive energy per pound of feed resulted in a slight improvement in fertility and hatchability. Robblee and Clandinin (1959) made comparisons between rations containing 15 and 17% protein in combination with productive energy levels of 700, 790 and 880 Calories per pound of feed. They were unable to demonstrate any…

Influence of Triparanol (M/E/R/29®) on Growth, Egg Production, and Cholesterol Metabolism of Chickens

A REPORT by Avigan et al. (1960) shows that triparanol2 lowered serum cholesterol of male rats. The reduction in serum cholesterol varied according to the concentration of triparanol fed and the length of time it was fed. Growth was reduced as dosage was increased. Steinberg and Avigan (1960) postulated that triparanol blocks cholesterol synthesis at the desmosterol to cholesterol step. With in vitro liver homogenates, triparanol treatment inhibited the conversion of desmosterol to cholesterol. Because of the work of Steinberg and Avigan, it was thought that triparanol might also lower serum cholesterol in the chick and possibly even lower egg yolk cholesterol values.EXPERIMENTAL PROCEDUREChick Experiment 1. Duplicate pens of 30 broiler-type chicks, with equal numbers of males and females in each pen, were fed rations containing 0, 25, 50 or 100 mg. triparanol per pound of feed. The basal chick ration is shown in Table 1. The birds …

Protein Energy Relationships in the Diet of the Chick

THE REPORT of Scott et al. (1947) has stimulated a great deal of work on the utilization of high energy rations for the production of broilers. Hill and Dansky (1950) indicated a relationship between the level of protein and productive energy in the diet of chicks. These authors observed a reduced growth rate in chicks fed a diet containing less than 20% protein but high in productive energy. Normal growth was obtained when the level of productive energy was reduced. Combs and Romoser (1955) concluded that the growth rate in broilers to 7 weeks of age was not affected until more than 41.5–42.0 Calories of productive energy per pound of feed were supplied for each pound of protein. The influence of different productive energy to protein ratios upon the growth and feed efficiency of chicks has been reported by many workers. Among these, Vondell et al. (1958) concluded that …

The Influence of Dietary Energy Level, Energy Source, Breed and Sex on Vitamin A Requirement in the Chick

REVIEW OF LITERATURETHE dietary requirement for vitamin A in the young chick has been estimated to be 1,200 U.S.P. units per pound of feed (National Research Council, 1954). Although this estimate is based on work prior to 1954 (Wilson et al., 1936; and Record et al., 1937), which showed that levels of 1,200 U.S.P. units and lower were sufficient for normal growth and health of chicks, considerable question has arisen as to its adequacy under current conditions.The development of the faster growing bird, the advent of the high energy ration and the production of vitamin A supplements of increased stability are among various factors which may be influential in changing the dietary requirement for vitamin A. Thus it is important that the requirements for such nutrients be reevaluated periodically. In some recent work, Scott et al. (1957), found that 400 to 600 U.S.P. units of vitamin A were …

A study of pathogenic factors in experimental bovine oesophagostomosis. I. An assessment of the importance of anorexia

Pathogenetic factors in bovine oesophagostomosis have been investigated by comparing, in calves of the same breed subject to equalized feeding in pairs, the state of health and thriftiness of infected and control groups. Infection was produced by the administration of 7000 Oesophngosfomum rutiintum larvae. The resulting disease varied from mild to moderately severe in its effects, and was of comparatively brief duration. First signs were seen at 3-5 weeks, improvement began at 10 weeks, and the animals were recovering well at 14 weeks. Infected calves developed an anorexia which was first made evident by a rapid reduction in the mean daily feed intake during the fourth week following infection, succeeded by a slow return to the pre-infection level of' intake about 14 weeks later. In control calves, the same reduction in food intake was imposed over the same period by withholding some of the ration. In control calves the only definite departure from normal was a reduction in the rate of gain in body weight that would be expected in similar calves fed ad libitum, and some retardation in growth. Infected calves on the same feed intake as control animals showed a much greater departure from normal in respect of rate of gain in weight, and their growth was more severely retarded. The mean feed utilization of these calves was 0.039 lb per pound of feed, as compared with 0.095 lb per pound of feed for the worm-free controls. Furthermore there was observed, only in the infected animals, diarrhoea, a normochromic normocytic anaemia, and a hypoproteinaemia. The most severe pathological changes in the hosts occurred when the helminths were in the early fifth stage of development. It is concluded that anorexia is a factor which, through reduction of food intake, contributed considerably to pathogenesis. Other factors together exercised an effect almost as great. These other factors have yet to be investigated and defined.

The Effects of Different Protein and Energy Levels on the Growth of Turkey Poults

THE EFFECTS of various protein and energy levels on the growth rate of chicks and turkey poults has been investigated by many workers in recent years. Sunde (1956) fed diets to chicks consisting of 20 and 28 percent protein and with energy levels ranging from 655 to 932 Calories of productive energy per pound of feed. The results of this study indicated that a high protein, low-energy diet produced a reduction in growth rate with a decreased efficiency of feed utilization. When the energy level of this diet was increased, the weight of the birds at four weeks of age was increased and a greater efficiency of feed utilization was realized. A significant increase in the growth rate and feed efficiency of chicks fed a diet containing 10 percent tallow was reported by Aitken et al. (1954) when the protein content was increased from 22 to 25 percent. Biely and …

Restricted Feeding of Broiler Type Replacement Stock

IN RECENT years there has been much interest in the various feeding systems in growing replacement stock for both egg strain and meat strain pullets. These feeding systems have principally been a comparison of full-feeding (allowing the birds to consume all they will eat of a “high” energy type ration) versus restricted feeding (allowing the birds less feed daily than they would consume). Recent emphasis has been on the various means of accomplishing restriction. These means are: (1) limiting the feeding time of the bird, (2) limiting the feed intake of a “high” energy grower formula, (3) limiting the mash feeding to a certain number of days per week, (4) using a grain-mash system, or (5) adding fiber to the formula to give the desired energy level per pound of feed. The latter method, of adding fiber at levels of 6–20% of the ration, is the more recently developed …

The Effect of Diethylstilbestrol-Methimazole and Dienestrol Diacetate on Turkey Broilers

THE ability of administered estrin to produce lipemias in birds was demonstrated by Lorenz et al. (1938). Lorenz (1943) demonstrated that diethylstilbestrol could be used for fattening cockerels when it was implanted subcutaneously. Later Lorenz (1944) reported an increase in abdominal fatty tissue in turkeys when they were treated with diethylstilbestrol. Lorenz (1945) also reported that when diethylstilbestrol pellets were administered to chickens by subcutaneous implantation there was a marked increase in the fat content of the muscle tissue and in the quantity of depot fat. Thayer et al. (1945) found 3,4 dianisylhexene-3 to be more efficient for fattening chickens than diethylstilbestrol when fed orally. Levels of 40 to 50 mg. of dianisylhexene per pound of feed fed for a 3 to 4 week fattening period did not appear to effect growth rate, but body fat was increased. Gassner and Wilgus (1948) found that alpha-estradiol and methoxybisdehydrodoisynolic acid were ineffective …

The Occurrence of Leg Weakness in Mature Turkeys

SCOTT (1950), reported that the occurrence of enlarged hocks at 2 to 4 weeks of age in turkey poults increased the incidence of leg weakness or perosis in mature turkeys. Later, Scott (1953) demonstrated that the addition of 30 mg. of niacin and 5 mg. of alpha tocopheryl acetate per pound of feed completely prevented the early condition. Also, the addition of the same level of alpha tocopheryl acetate and 20 mg. of niacin per pound to the developing ration prevented the mature leg condition in turkeys that showed a high incidence of the leg abnormalities as poults. Single supplementation of niacin or alpha tocopheryl acetate to the developing diet had no beneficial effect.Slinger et al. (1954) fed starting and developing mashes containing all combinations of 0.3, 0.5 and 0.7 percent inorganic phosphorus and 0, 2.5, 5.0 and 7.5 I.U. of vitamin E per pound. Vitamin E and phosphorus …

Development of Rumination in the Young Calf

Summary The activities of 12 Jersey and 14 Holstein calves, with special attention to rumination, were observed for a full day's time each 2 wk. from 1–2 to 15–16 wk. of age. Rumination had begun in 18 of the calves in the first 2 wk., 25 in the second 2 wk., and in all calves in subsequent periods. Rumination time increased rapidly to an average of nearly 5 hr. per day at 6–8 wk. of age. Thereafter, the rate of increase in rumination time was reduced. Rumination time was positively correlated with dry feed consumption, but less time per pound of feed was spent ruminating as the calves aged. The appearance of rumen contents of 17 calves sacrificed at 12–22 days of age indicated that more than half of the calves were ruminating effectively at 2 wk. of age. Observations are also presented of the times spent eating and drinking and lying down, as well as correlations between blood glucose content and rumination time.

Effects of Certain Antibiotics on Protein Utilization by Broilers

ABSTRACT RESULTS indicative of a possible “sparing” effect of low levels of certain antibiotics on the protein requirement of broilers were reported by Machlin et al. (1952), Weakley et al. (1953), and West and Hill (1955). The work of Scott et al. (1952), Slinger et al. (1952), Biely et al. (1952) and Matterson et al. (1952) indicated that no sparing effect of antibiotics on protein occurred in chicks. White-Stevens and Zeibel (1954) found that low levels of aureomycin produced the greatest effect on growth at a protein level of 16 percent, but that high levels of aureomycin gave the greatest effect on growth at a protein level of 22 percent. Energy levels were held relatively constant for the different protein levels, varying from 900 to 950 Calories of productive energy per pound of feed. The work of Combs and Romoser (1955) showed that the protein needs of the young chicken varies . . .

The Effect of Different Levels and Prolonged Supplementation of Chlortetracycline upon Roughage Digestion by Sheep

Three experiments were conducted with 38 wether lambs, that weighed an average of about 65 lb. each, to determine the effect of chlortetracycline on the apparent digestibility of feed constituents of a ration which consisted primarily of low quality roughage. The rations were composed of 80% ground corncobs and 20% concentrate mixture. In Experiment 1 the basal ration was supplemented with 10 mg. of chlortetracycline and chlortetracycline as Aurofac 2A per pound of feed. In Experiment 2 the basal ration was supplemented with chlortetracycline and chlortetracycline as Aurofac 2A, each at the 1 and the 2-mg. levels per pound of feed. Experiment 3 was a repetition of Experiment 2, except the levels of antibiotic fed were increased to 5 and 10 mg. per pound of feed, and the collection period consisted of three consecutive 10-day collection periods. In all experiments the initial supplementation of 5 and 10 mg. of chlortetracycline or Aurofac 2A caused a loss of appetite within 40 to 72 hours. All levels of chlortetracycline supplementation significantly decreased the apparent crude fiber digestibility except the 1 mg.level of chlortetracycline as Aurofac 2A in Experiment 2. This same trend was present for dry matter, organic matter, and nitrogen-free extract. As the level of chlortetracycline was increased from one to two and from 5 to 10 mg. the decrease in apparent digestibility of ration constituents became greater. In Experiment 3 there was a definite period effect in the chlortetracycline supplemented groups with a recovery of apparent digestibility of ration constituents in Period 3. The average apparent digestibility of crude fiber for both sources of chlortetracycline at the 10-mg. level for Periods 1, 2 and 3 in Experiment 3 were reduced by 18.4, 11.5 and 5.4%, respectively. This same trend of recovery was present for dry matter, organic matter and nitrogen-free extract. The implications of these findings are discussed.

Response to Diethylstilbestrol Injections of Growing Chicks Fed Various Protein Levels

LORENZ (1943) demonstrated that diethylstilbestrol could be used for fattening cockerels when it was implanted subcutaneously. Thayer et al. (1944) reported that feeding estrogens in fattening rations produced high quality, fully fattened market chickens. Thayer et al. (1945) found 3, 4 dianisylhexene-3 to be more efficient for fattening poultry than diethylstilbestrol when fed orally. Levels of 40 to 50 mgs. of dianisylhexene per pound of feed, fed for a 3 to 4 week fattening period, did not appear to affect growth rate but body fat was increased. Improvement in the market quality of birds was noted by Sykes et al. (1945) when the birds were fed diethylstilbestrol up to 12 weeks of age. No consistent difference in feed consumption or feed utilization of the lots was reported by these workers. Glazener and Jull (1946) have shown that diethylstilbestrol fed for a three-week period improved dressing appearance and rate of gain …