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PubMed2003

Evaluation of nonfeed removal methods for molting programs.

An experiment was conducted using 336 White Leghorn hens (60 wk of age) randomly assigned to one of four treatments that consisted of feed removal for 4 or 10 d or no feed removal with ad libitum access to 95% corn or 95% wheat middlings molt diets that contained supplemental minerals and vitamins. At the end of the 4- or 10-d feed removal period, hens on these treatments were provided with the corn molt diet for 24 or 18 d, respectively. Hens on the corn or wheat middlings treatments were fed the diets for 28 d. At d 28, hens on all treatments were fed a corn-soybean meal (16% CP) layer diet for 40 wk (64 to 104 wk of age). Both feed removal and the wheat middlings treatments resulted in total cessation of egg production within 8 d. Egg production of hens fed the corn molt diet had decreased to 3% by d 28. Body weight loss for hens fed the corn or wheat middlings diet was approximately 15 and 8% at d 28, respectively. Hens fed the wheat middlings diet returned to production slightly faster than hens on the other treatments. Postmolt egg production and egg mass (wk 5 to 44) were generally higher for the wheat middlings and 10-d feed removal treatments than for the corn or 4-d feed removal treatments. There were no consistent differences in mortality, egg weight, egg specific gravity, feed efficiency, and layer feed consumption among treatments. This research indicates that diets with high corn or wheat middlings, particularly wheat middlings, are effective nonfeed removal methods for molting hens.

Animal Feed↗

PubMed2003

Effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on growth and immunological measurements of starter pigs, and the efficacy of a polymeric glucomannan mycotoxin adsorbent.

An experiment was conducted to investigate the effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on growth and immunological parameters of starter pigs. A polymeric glucomannan mycotoxin adsorbent (GM polymer, Alltech Inc., Nicholasville, KY) was also tested for its efficacy in preventing Fusarium mycotoxicoses. A total of 150 starter pigs (initial weight of 9.3 +/- 1.1 kg) were fed one of five treatment diets (six pens of five pigs per diet) for 21 d. Diets included control, low level of contaminated grains, high level of contaminated grains, high level of contaminated grains + 0.20% GM polymer, and pair-fed control for comparison with pigs receiving the high level of contaminated grains. Feed intake and cumulative weight gain of pigs decreased linearly with the inclusion of contaminated grains in the diet throughout the experiment (P < 0.0001). Weight gains recovered, however, during wk 3 (P > 0.05). There was no difference between the pair-fed group and the pigs fed the diet containing the high level of contaminated grains in terms of weight gain or feed efficiency (P > 0.05). Feeding contaminated grains linearly increased the serum albumin:globulin ratio (P = 0.01), whereas serum urea concentrations and gamma-glutamyltransferase activities responded in a quadratic fashion (P = 0.02). When compared with the pair-fed pigs, serum concentrations of total protein (P = 0.01) and globulin (P = 0.02) were decreased in pigs fed the diet containing the high level of contaminated grains. The feeding of contaminated diets did not significantly alter organ weights expressed as a percentage of BW, serum immunoglobulin concentrations, percentages of peripheral blood lymphocyte subsets, contact hypersensitivity to dinitrochlorobenzene, or primary antibody response to sheep red blood cells (P > 0.05). It was concluded that most of the adverse effects of feeding Fusarium mycotoxin-contaminated grains to starter pigs were caused by reduced feed intake. Although supplementation of GM polymer to the contaminated diet prevented some toxin-induced changes in metabolism, it did not prevent the mycotoxin-induced growth depression under the current experimental conditions.

Adsorption↗

PubMed1984

Impact of northern fowl mite on broiler breeder flocks in North Carolina.

The impact of a northern fowl mite (NFM), Ornithonyssus sylviarum (Canestrini and Fanzago), infestation on broiler breeder layers in the field was evaluated by comparing flocks in two adjacent houses (ca. 5,000 birds each). The NFM-free birds produced 3,158.7 dozen more eggs than NFM-infested birds, which was equal to 7.7 eggs per hen housed more than infested birds over the life of the flock. Feed efficiency was affected; feed costs for NFM-infested birds ranged from $ .01 to $ .06/dozen higher than the feed costs for NFM-free birds.

Animal Feed↗

PubMed1995

Heterosis and overdominance following long-term selection for body weight in Japanese quail.

Although nonadditive genetic variation is more important in crosses among laying stocks than among meat stocks, development of special sire and dam lines to control the release of primary lines results in broilers being the product of three- or four-way crosses. Therefore, nonadditive genetic effects are important in meat stocks because of opportunities to combine stocks that complement each other. Four experiments were conducted to investigate heterosis and overdominance arising from crossing Japanese quail lines originating from the same base population and selected long-term ( > 85 generations) for high 4-wk BW under different selection environments. The different selection environments were established by feeding different levels of CP (28 and 20%) and different levels of thiouracil (0 and.2%). Estimates of heterosis were high for hatch of total eggs ( > 25%) and liveability (12 to 47%), and low for hatch weight (2 to 4%). Overdominance estimates followed similar patterns but were of lower magnitude. Percentage heterosis estimates for BW were high at 1 wk (20 to 30%) and declined linearly to 5 to 10% at 4 wk when quail were fed 28 and 24% CP diets. Contrariwise, when fed low-CP (20%) diets, heterosis values were low initially and remained stable or increased across age. Data obtained from measuring feed intake and feed efficiency indicated that heterosis for BW was closely related to change in feed intake. Heterosis values for feed intake closely followed those for BW, including the decline across age. Conversely, heterosis appeared to be absent for feed efficiency, except at 1 wk. Similar to heterosis estimates, overdominance estimates were high initially and declined across age and were more clearly demonstrated under the 24 and 28% diets. It was concluded that considerable heterosis is present for BW in Japanese quail following the crossing of lines selected long-term for high BW, but that it is dependent on both environment (diet) and age.

Age Factors↗

PubMed1985

Efficiency of feed energy utilization for protein and fat gain in Hereford and Charolais steers.

Two multiple regression models were used to estimate energetic efficiency of protein and fat gain for 84 grade British steers, predominantly Hereford, and 84 Charolais steers using data obtained from a comparative slaughter feeding trial. In Model One, metabolizable energy intake was regressed on energy gain as fat and protein; the intercept was an estimate of maintenance. For Model Two, maintenance requirements were estimated by regression of log heat production (kcal/kg.75) on metabolizable energy intake (kcal/kg.75) and iterating to the point at which heat production was equal to metabolizable energy intake. Energy intake above maintenance was then regressed on energy gained as fat and protein. Results from Model One showed the efficiencies of protein and fat gain to be 10 and 49%, while Model Two indicated these efficiencies were 11 and 58%. Breeds did not appear to differ significantly in the efficiency with which they used metabolizable energy for protein or fat deposition.

Animal Feed↗

PubMed1990

General and histopathological results of a two-year study of rats fed semi-purified diets containing casein and soya protein.

Two semi-purified diets, identical except for protein (soya or casein), and a Purina chow diet were fed to groups of Sprague-Dawley rats and compared over a 22-month period for effects on body weight, organ weight, feed consumption, feed efficiency, protein efficiency, organ-to-body-weight ratios, certain organ mineral levels, gross pathology and histopathology. Feed efficiency, protein efficiency, body weight, and most organ weights were higher in the groups fed soya and casein, while feed consumption and most organ-to-body-weight ratios were relatively lower. Significant increases in the final pathology findings in the groups fed soya and casein included nephrocalcinosis (in females), hepatocellular vacuolization, gastric trichobezoars (hairballs), ulcerative pododermatitis (hock ulcers) and splenomegaly. This study demonstrates that the long-term feeding of semi-purified diets is feasible. Moreover, the differences observed between the protein sources, that is, soya and casein, were minimal, which suggests that either protein source is acceptable for long-term feeding studies.

Animals↗

PubMed1989

Effect of testosterone propionate on performance and carcass characteristics of heifers and cows.

Two experiments were conducted to evaluate the effect of testosterone on growth and composition of cattle. In the first experiment, crossbred yearling heifers (n = 48) were assigned to four treatments: 1) control (no implant), 2) Synovex-H implants on d 1 and 84, 3) one testosterone propionate implant administered on d 1 and a second on d 84 and 4) two testosterone propionate implants administered on d 1. Heifers were fed a high-energy diet for the 157-d study. Implanting with the high-testosterone treatment improved (P less than .05) daily gain and feed efficiency compared with the other treatments. Marbling score was reduced (P less than .05) with the high-testosterone treatment. In Exp. 2, mature cows (n = 36) were assigned to one of three feeding periods (0, 42, or 84 d) with the cows fed 42 or 84 d subdivided into two groups (implanted with testosterone propionate or nonimplanted control). Cows were fed a high-energy diet and slaughtered at the end of each feeding period. Testosterone did not influence (P greater than .05) feedlot performance. Increased time on feed reduced (P less than .01) daily gain (live weight basis) and feed efficiency but did not influence feed intake. Testosterone treatment had little influence on the fat and moisture contents of the carcass soft tissue or on the palatability characteristics of loin steaks. Time on feed increased lean muscle mass and carcass fat (P less than .05). Sensory traits were improved at 42 d on feed (P less than .05), but no further sensory improvement was observed at 84 d.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Research note: nutritive value of poultry by-product meal. 3. Incorporation into practical diets.

Studies were conducted to investigate the value of poultry by-product meal (PBPM) when incorporated into practical diets at low levels (5 to 10%). Samples from one plant, a Monday morning sample (fresh broiler waste) and a Friday afternoon sample (broiler and hatchery waste and dissolved air flotation sludge) were compared to a sample from another plant (fresh broiler waste). When the samples were incorporated at the 5% level into isocaloric, isonitrogenous corn-soy meal-based practical diets, no differences in 20-day gain or feed efficiency could be detected between the samples or in comparison with the effects of feeding an all-plant-based control diet in two experiments. Chick growth and feed efficiency were significantly depressed when PBPM was incorporated into the diet at the 10% level.

Animal Feed↗

PubMed2001

Effects of water sulfate concentration on performance, water intake, and carcass characteristics of feedlot steers.

Two hundred forty single-source, cross-bred steers (304 kg) were used to evaluate the effects of various water sulfate concentrations on performance, water intake, and carcass characteristics of feedlot steers. Cattle were stratified by weight and assigned within weight blocks to five water treatments. Averaged over time, actual water sulfate concentrations (+/- SEM) were 136.1 (+/- 6.3), 291.2 (+/- 15.3), 582.6 (+/- 16.9), 1,219.2 (+/- 23.7), and 2,360.4 (+/- 68.2) mg/L, respectively. Weather-related data were recorded. Increasing water sulfate concentration resulted in linear decreases in ADG (P < 0.01) and gain:feed ratio (P < 0.01) and a quadratic effect on water intake (P = 0.02) and tended to quadratically increase then decrease DMI (P = 0.13). Sulfate x period interactions were evident for DMI (P = 0.01), ADG (P < 0.01), and feed efficiency (P < 0.01). Time had quadratic effects on DMI, water intake, ADG, and feed efficiency (P < 0.01 for all models). Increasing water sulfate concentration resulted in linear decreases in final weight, hot carcass weight, and dressing percentage, a linear increase in longissimus muscle area, and a quadratic effect on fat thickness over the 12th rib and predicted yield grade (P < 0.05 for all dependent variables). Mean daily temperature explained 25.7% of the observed variation in water intake. Other factors that explained a significant (P < 0.01) amount of variation in water intake were BW, DMI, water sulfate concentration, barometric pressure, wind speed, and humidity. High water sulfate concentrations had a significant and deleterious effect on performance and carcass characteristics of feedlot steers. Increasing the sulfate concentration in water may have resulted in a functional water restriction early in the trial when ambient temperatures were greatest. However, toward the latter stages of the trial, cattle supplied higher-sulfate water had higher ADG and FE. These improvements later in the trial may represent compensatory gain associated with decreased ambient temperature and water requirements. Averaged over time, a water sulfate concentration of greater than 583 mg/L, equivalent to 0.22% of the diet, decreased feedlot performance.

Age Factors↗

PubMed1984

The effect of light regime on growth and pattern of body fat accretion of broiler chickens.

A seven week serial slaughter experiment was conducted with male and female broiler chickens to determine the effect of photoperiod on body growth rate and pattern and rate of fat deposition. The two light regimes compared were constant light and a 16 hour light:8 hour dark photoperiod. Males grown under the 16L:8D photoperiod consumed less feed and grew less rapidly than males under constant light. The slower rate of growth was apparently due entirely to less feed consumption, since feed efficiency of males was unaffected by light treatment. Females reared under 16L:8D also grew less rapidly than under constant light. However, the difference was much more pronounced than in males, and was not due to reduced feed consumption, rather to less efficient feed utilization. Females grown under 16L.8D exhibited a slower rate of increase in percent daily fat gain than did females grown under constant light. At seven weeks of age, total body fat content of females averaged 12% less when grown under 16L:8D. Rat and pattern of fat gain in males was unaffected by light treatment. The incidence of leg abnormalities was substantially lower for both sexes reared under 16L:8D.

Adipose Tissue↗

PubMed1984

Effects of dietary thyroid hormones on growth and serum T3, T4, and growth hormone in sex-linked dwarf chickens.

Dwarf pullets fed with either T3 or T4 at 0.1, 1.0, and 10.0 ppm for 2 weeks showed no improvement in their body weight gain as compared with birds that were fed a control diet. Birds fed T3 or T4 at 10.0 ppm showed poorer growth, body weight gain, and feed efficiency than control birds. Pullets fed 1.0 ppm of T3 showed significantly better feed efficiency than control birds. Serum T3 concentrations were significantly higher when birds were fed 1.0 ppm of T3 or 10.0 ppm of T3 or T4. Plasma T4 concentrations were also higher in T4 fed birds (1.0 ppm and 10.0 ppm), but were significantly lower in T3 fed birds (1.0 ppm and 10.0 ppm) than in control birds. In birds fed T3 or T4 at 1.0-ppm and 10.0-ppm levels serum growth hormone concentrations were significantly lower as compared with control birds. In conclusion, exogenous T3 and T4 did not correct the sex-linked dwarfism of dwarf chickens. Such dwarfism is characterized by low circulating levels of T3 and T4.

Animals↗

PubMed1975

Debeaking method for Bobwhite quail.

Four experiments were conducted to determine the suitability of various debeaking procedures for Bobwhite quail at hatching or at one week of age. Two experiments were conducted using a "precision" type debeaking method with the following treatments: control; debeaked at hatching with debeaker guide plate holes of 2.38 or 2.78 mm; debeaked at seven days of age using guide plate holes of 2.38, 2.78 or 3.18 mm. Two experiments tested a "touch-burn" method at hatching with the following treatments: control; burned 1/4 distance to nares; and burned 1/2 distance to nares. The "precision" type methods at hatching or seven days of aged reduced mortality from cannibalism; however, these methods were found to be relatively slow and difficult, and the birds lacked uniformity in beak and body size at five weeks of age. Burning 1/2 distance to nares was too severe, causing a reduction in body weight and poor feed efficiency. Burning 1/4 distanct to nares gave the most favorable results: growth and feed efficiency as good or better than controls, uniform birds and decreased cannibalism.

Animals↗

PubMed1991

Divergent selection for growth in Japanese quail under split and complete nutritional environments. 5. Feed intake and efficiency patterns following nineteen generations of selection.

High (H) and low (L) quail lines divergently selected for 4-wk BW under complete-diet (CD) and split-diet (SD) environments were evaluated to examine changes in feed intake and feed efficiency before and after the age at selection. Progeny from the four quail lines (H-SD, L-SD, H-CD, L-CD) were fed the CD in Generation 17 and the SD in Generation 19. The BW of H-line quail were highest under their respective selection environments, and the BW of quail in the L lines were highest under reciprocal environments. However, the BW of the two H lines were similar as were those of the two L lines. Relative growth rates of H-line quail were superior to those of L-line quail for the first 2 wk posthatch but L-line rates were superior after Week 4. However, the BW of H-line birds were always higher than for the L-line birds. Adjusted feed intake (grams of feed per 100 g of BW) values for the H lines were similar but lower than values for the L lines. Differences in adjusted feed intake between the H and L lines from 1 to 10 wk remained constant, although adjusted feed intake declined with age in all lines. Feed efficiencies (grams of gain divided by grams of feed) were superior in the H lines for Weeks 1 through 3 and superior in the L lines for Weeks 5 through 9. The same relative shifts between lines were observed in relative growth rates. Therefore, feed efficiency, in addition to feed intake, appears to play an important role in the divergence of BW in the H- and L-quail lines.

Abdomen↗

PubMed1981

Effect of feed or water restriction on basal and TRH-stimulated growth hormone secretion in the growing turkey poult.

Both feed and water restriction of growing turkeys resulted in an increase in the basal levels of plasma growth hormone (GH). Restricted birds also showed an increased response to thyrotropin-releasing hormone (TRH) stimulation. These changes were significantly greater in feed-restricted birds than in the water-restricted birds. After return to ad lib conditions, basal plasma GH levels remained elevated above control levels in both previously restricted groups. However, the GH response to TRH stimulation returned to normal during this period. The increase in GH secretion during undernutrition is a metabolic adjustment consistent with the known role of GH in glucose, protein and fat metabolism. The elevated GH levels present after return to adequate nutrition may aid compensatory growth. Feed and water restriction were equally effective in limiting the growth of young turkey poults. Body weight gain and feed efficiency were severely affected during the first 3 weeks of restriction, but improved during the 4th week. Return to ad lib conditions resulted in compensatory growth and markedly improved feed efficiency in both restricted groups. Feed-restricted birds showed a significant increase in water consumption after 8 days of restriction. This polydipsia may result from intermittent feeding of hungary animals. Water consumption returned to normal after 1 week of ad lip feeding. Birds restricted in water consumption voluntarily limited their feed intake to a level only slightly higher than that of the feed-restricted group. When water was supplied ad lib, these birds immediately resumed normal feed consumption.

Animal Feed↗

PubMed1977

Protein for calves on a limited milk-early weaning system.

Complete pelleted calf starter rations were fed to Holstein heifer calves on a limited milk-early weaning program from 3 days to 12 wk of age. Five rations fed to each of 10 calves were to contain crude protein percentages of 10, 12.5, 12.5 with 97% urea, 15, and 15 with 1.1% urea (as fed). The digestible protein:digestible energy ratios (g digestible protein/Mcal digestible energy) of the rations (in same order) were 23.4, 30.7, 28.8, 36.4, and 41.5. Average birth weight was 42.9 kg and weaning weight at 4 wk, 52.8 kg. Treatment effects on feed intake, average daily gain, and feed efficiency were analyzed after adjustment of birth weight and removal of effects of block and location. Feed intake for 12 wk was greater for 15% crude protein with 1.1% urea than for either 12.5% ration but not different from 10% protein. Average daily gain was increased for 15% protein rations compared to 10 or 12.5% protein. Gain by claves fed 10% protein was equal to that by those fed 12.5% protein. Feed efficiency during wk 5 to 12 was improved for 15% with vegetable protein compared to 10% crude protein or the 12.5% crude protein ration with vegetable protein. There were no differences in intake, gain, or efficiency between urea and vegetable protein.

Animal Feed↗

PubMed1987

Effects of different methods and severity of growing period feed restriction on growth and laying performance of white Leghorns.

Two experiments were conducted to study the effects of different methods of feed restriction and severity of feed restriction during the growing period on pullet growth and laying performance of White Leghorns. In Experiment 1, ad libitum feeding of the low protein diet (supplemented with amino acids) was the only treatment among four feed restriction treatments that did not significantly (P greater than .05) influence growing period feed consumption and body weight gain. The smallest body weight gain was obtained among birds subjected to the daily restrictive feeding (DRF) treatment. Ad libitum feeding of the low energy diet resulted in a significantly (P less than .05) poorer growing period feed efficiency than any other treatment. Both energy and protein utilization efficiencies for body weight gain were significantly (P less than .05) hindered by the skip feeding treatment. Although DRF birds consistently had higher egg production from 36 to 76 weeks of age than birds in any other group, overall average percent hen-day egg production from 20 to 76 weeks of age was not significantly (P greater than .05) improved by the DRF treatment. Also, in Experiment 2, various levels of DRF during the growing period did not significantly (P greater than .05) improve average percent hen-day egg production. Laying house mortality, feed efficiency, and egg weight were not significantly (P greater than .05) different among treatments (Experiments 1 and 2). Results of these experiments indicate that DRF was the most effective method of controlling growth rate and that neither method of feed restriction nor severity of feed restriction during the growing period significantly (P greater than .05) improved laying performance.

Animals↗

PubMed1987

Immunologically mediated growth depression in chicks: influence of feed intake, corticosterone and interleukin-1.

The effects of an immune response on growth and feed efficiency in chicks and the role of interleukin-1 (IL-1) and corticosterone (Cort) as mediators of the response were investigated. Daily injections of either sheep red blood cells or the inflammatory agent Sephadex resulted in significantly (P less than 0.05) lower rates of weight gain, feed intake and efficiency of feed utilization than controls fed ad libitum, indicating an immunologically mediated stress. Feeding control chicks the same amount of diet as that consumed by immunologically challenged chicks did not completely equalize rates of weight gain. Injections of a crude preparation of IL-1, but not Cort, resulted in weight gain, feed intake and efficiency of feed utilization that were similar to those of immunologically challenged chicks. The concentrations of IL-1 and Cort, measured by bioassay and radioimmunoassay, respectively, in serum from immunologically challenged chicks were significantly higher than in nonchallenged chicks. To determine the influence of IL-1 and Cort on protein accretion in skeletal muscles, the extensor digiti communus and ulnaris lateralis were incubated in the presence of these two hormones at concentrations similar to that seen in serum after an immunologic challenge. Cort did not affect the rate of protein degradation but resulted in rates of protein synthesis that were significantly lower than controls. IL-1 did not affect the rate of protein synthesis but resulted in rates of protein degradation that were about 24% greater than controls.

Animals↗

PubMed2000

Inactivation of the mouse melanocortin-3 receptor results in increased fat mass and reduced lean body mass.

Genetic and pharmacological studies have defined a role for the melanocortin-4 receptor (Mc4r) in the regulation of energy homeostasis. The physiological function of Mc3r, a melanocortin receptor expressed at high levels in the hypothalamus, has remained unknown. We evaluated the potential role of Mc3r in energy homeostasis by studying Mc3r-deficient (Mc3r(-/-)) mice and compared the functions of Mc3r and Mc4r in mice deficient for both genes. The 4-6-month Mc3r-/- mice have increased fat mass, reduced lean mass and higher feed efficiency than wild-type littermates, despite being hypophagic and maintaining normal metabolic rates. (Feed efficiency is the ratio of weight gain to food intake.) Consistent with increased fat mass, Mc3r(-/-) mice are hyperleptinaemic and male Mc3r(-/-) mice develop mild hyperinsulinaemia. Mc3r(-/-) mice did not have significantly altered corticosterone or total thyroxine (T4) levels. Mice lacking both Mc3r and Mc4r become significantly heavier than Mc4r(-/-) mice. We conclude that Mc3r and Mc4r serve non-redundant roles in the regulation of energy homeostasis.

Adipose Tissue↗