Responses of chicks to dietary supplements of copper sulphate

Sixteen groups of 20 1‐d‐old male chicks of a hybrid laying strain were reared for 25 d and given free access to diets supplemented with o, 100, 200 or 350 p.p.m. copper (as CuSO4.5H2O), with or without antibiotic. The unsupplemented diet, based on cereals, fish and soyabean meals, contained 9.6 p.p.m. copper. Live‐weight gains, food intakes and hepatic copper concentrations were measured.

The mean hepatic copper concentration was 10.0 p.p.m. (of dry tissue) in 1‐d‐old chicks, and after 25 d rose to a mean concentration of 15.3 p.p.m. in birds fed the diets without added copper and 17.6, 32.9 and 148 p.p.m. in birds fed diets supplemented with 100, 200 and 350 p.p.m. copper respectively.

In relation to copper supplementation, two trends in live‐weight gain were noted: (1) an increase in weight gain reaching an average of +2.3 per cent at 100 p.p.m. copper, (2) a depression of weight gain at 350 p.p.m. copper averaging ‐7.5 Per cent. Only the latter trend was statistically significant. Chicks given the antibiotic supplement gained 3.6 per cent more weight than those fed the diets without antibiotic.

All these differences in weight gain were associated with differences in food consumption; food conversion efficiency was almost uniform. There were no overt signs of poisoning nor any. apparent relation between the weight gains and hepatic copper concentrations of individual chicks given the 350 p.p.m. copper supplement.     

Food intake and growth in chickens given food in the wet form with and without access to drinking water

1. Individually caged growing chickens were offered a commercial grower food mixed with 1–5 to 2^‐25 times the weight of water and the effects, compared to giving the same food in air‐dry form, on food intake, body weight gain and carcase composition were investigated.

2. Male broilers (24) were given either a grower food in the air‐dry form with access to drinking water or the same food mixed with 2–0 parts of water (700 g water/kg of mixed food) with no drinking water from 28 to 49 d of age. From 49 to 63 d all birds were given dry food and drinking water and were then killed for carcase analysis. Food intake and weight gain were significantly increased during the wet‐feeding period, as was carcase protein but not abdominal or carcase fat at the end of the experiment.

3. Five male broilers were given each of 5 dietary treatments containing 0 (control), 1.5, 1.75, 2.0 and 2.25 times added water (640, 673, 700 and 723 g water/kg) from 28 to 49 d. Food intakes, body weight gains and carcase weights were significantly increased for all water additions compared with dry food, but there were no significant differences between different water additions.

4. Female broiler chicks responded to wet feeding (700 g water/kg) in a similar manner to males and the dry matter approximate digestibility was increased from 0.65 for the dry food to 0.73 for the wet.

5. Cockerels of an egg‐laying strain did not increase their intake of dietary dry matter when it was fed in the wet form (700 g water/kg), but there was a significant increase in body weight gain.

6. Male broilers were offered wet food (700 g water/kg) with or without access to drinking water. There was equal stimulation of food intake, growth and carcase weight with both wet‐feeding treatments.

7. Providing food mixed with sufficient water to give a porridge‐like consistency significantly increased weight gains in each of the five experiments and significantly improved food conversion efficiency in three of the five. It is not necessary to withold drinking water in order to obtain this effect.     

Effect of food and water deprivation on live‐weight shrinkage,eviscerated carcass yield and water absorption during chilling of Turkey carcasses

1. The effect of depriving turkeys of food or both food and water for 12 or 24 h prior to slaughter on live‐weight shrinkage, eviscerated carcass yield and water uptake by the carcass during chilling was studied.

2. Deprivation of both food and water more than doubled the live‐weight shrinkage caused by removal of food alone, and deprivation for 24 h doubled the live‐weight shrinkage caused by 12 h.

3. Reduction in eviscerated carcass yield was small (4 g/kg) when only food was removed for 12 h but was increased by deprivation of both food and water or by depriving for 24 h.

4. Carcass weight gain during chilling in ice and water was not influenced by pre‐slaughter treatment.     

The relationship of feeding patterns and obesity in dogs

The rates of dog obesity are increasing and a greater understanding of feeding patterns is required to combat the problem. This study examined relationships between dietary patterns and caloric intake, and nutrient content of foods fed as it relates to obesity in dogs in the United States. Sixty‐one owners and their dogs were enrolled, and lifestyle surveys, food frequencies, and 3‐day food records were collected. Significant differences in overall kcal intake per kilogram of body weight were found (p < 0.04). Crude fibre in dog food was positively associated with protein and negatively associated with fat regardless of the dog’s weight (p < 0.001). Lean dogs received significantly more crude fibre in relation to overweight dogs regardless of the number of treats they received (p < 0.01), and their diets had greater micronutrient densities (p < 0.03) suggesting that high fibre influences body condition. Additionally, owners who ate nutrient‐rich, calorie‐poor diets had normal weight dogs, and owners that fed more table scraps had overweight dogs. Regardless of body condition, 59% of dogs received table scraps, which constituted 21% of daily caloric intake. The nutrient density of scraps fed was variable and did not meet National Research Council’s recommendations for micronutrient adequacy.     

Evaluation of crab meal as a dietary ingredient for young Turkeys

Adding 3 or 6% crab meal to the diets of turkeys between 1 d and 4 weeks of age resulted in their average body weight being increased by 5.2 or 6.8% and food consumption by 4.2 or 5.8%. Efficiency of food utilisation was not significantly changed. However, the addition of 5% crab meal to the diets of turkeys between 4 and 8 weeks of age resulted in average body weight gain and food consumption being increased by 1.4 and 1.3% respectively (P>0.05).

By adding 5% herring fish meal to the diets of poults from 4 to 8 weeks, body weight gain was increased by 2.0% (0.05<P<0.1), but food consumption was decreased by 2.3% and efficiency of food utilisation was increased by 4.2% indicating that fish meal contains a larger quantity of metabolisable energy than crab meal.

The addition of erythromycin at a rate of 13.5 or 20.4 mg/kg increased body weight gain by 4.5% and efficiency of food utilisation by 4.4% during the period between 4 and 8 weeks of age. No significant interactions among the dietary factors on the measurements studied in these experiments were observed.     

Influence of food intake and sex on the growth and carcase composition of Pekin ducks

1. The effects of food intake on growth and carcase composition of male and female meat‐type Pekin ducks were investigated between 14 and 56 d of age and between 0.416 kg (14 d) and 2.5 kg live body weight.

2. Males grew faster between 14 and 56 d of age and contained less fat and more protein and water in the eviscerated carcase at 56 d than females.

3. For both sexes, food : gain ratio deteriorated as food intake increased from 0.49 ad libitum intake to ad libitum intake. Growth rate, carcase weight and carcase fat content increased linearly with increase in food intake. Carcase fat content at 56 d was more sensitive to change in the amount of food consumed than either growth rate or carcase weight.

4. Between 0.42 kg (14 d) and 2.50 kg live body weight, growth rate and food :gain ratio improved as food intake was increased from 0.61 ad libitum to ad libitum. Males grew faster and produced leaner carcases than females.

5. Carcase fat content at 2.50 kg live body weight (1.60 kg carcase) increased in a curvilinear fashion with increase in food intake, and the magnitude of the response was lower for females than for males. A similar interaction existed between the effects of sex and the amount of food consumed for the proportions of protein and water in the eviscerated carcase at 2.50 kg live body weight.     

The influence of graded levels of atmospheric ammonia on chickens

Studies have been carried out to ascertain the effects of ammonia on the performance of White Leghorn hens housed in various environments of defined temperature and humidity. At 18° C. and 67 per cent relative humidity, the use of atmospheres containing 105 p.p.m. of ammonia by volume, significantly reduced egg production after 10 weeks’ exposure. No effects were observed on egg quality. However voluntary food intake was reduced in ammoniated atmospheres and live‐weight gain was lower. No recovery in production occurred when the treated groups were maintained for a further 12 weeks in an atmosphere free of ammonia.

When White Leghorn hens were housed at an environmental temperature of 28° C., body weight declined. The decrease in live‐weight was greatest at the high ammonia concentration of 102 p.p.m., and was significant after only 1 week's exposure to ammonia. Food intake of the controls was approximately 25 per cent lower at 28° C. than at 18° C., whilst 100 p.p.m. of ammonia further reduced food intake by more than 10 per cent. In one experiment at 28° C., egg production was significantly reduced after 7 weeks' exposure to ammonia.

In a subsequent trial, a high protein, vitamin and mineral diet prevented the onset of any deleterious effects of ammonia on egg production, even though food consumption fell to 75 g./bird/day at 29° C., 43 per cent relative humidity and 104 p.p.m. of ammonia. When a diet low in energy level was fed to hens subjected to high concentrations of ammonia, their voluntary food intake did not increase, and their production deteriorated rapidly.     

The quantification of the effect of increasing levels of various fats on body weight gain, efficiency of food conversion and food intake of growing chicks

A study, based on data from the literature, was carried out to establish the quantitative effect of increasing levels of various fats on food intake, weight gain and efficiency of food conversion of growing chicks.

The fats concerned were soyabean oil, soyabean soapstock, maize oil, lard, grease and tallow. Their effect was studied by using regression analyses.

It was found that the addition of fat, both animal fats and vegetable oils, diminishes food intake. The food intake decreases significantly with rising percentages of fat according to a linear function. No differences in effect between various fats could be demonstrated.

The incorporation of various fats improves the weight gain, although the increase was not related to the amount of fat added. The improvement in weight gain differs from one fat to an other.

The addition of fats improves efficiency of food conversion, but varies according to the kind of fat. Here the improvement is correlated with the level of fat added.

The difference in improvement of food conversion can be only partially explained by differences in absorbability and metabolisable energy of the fats.

It is concluded that certain fats ameliorate the efficiency of food conversion and, in some cases, weight gain to a higher degree as may be expected from their metabolisable energy content. It might be possible that some fats possess one or more factors which improve the efficiency of metabolisable energy or exert a protein anabolic action.     

Growth and the plasma concentrations of growth hormone and prolactin in chicks: Effects of “environmental enrichment”, sex and strain

1. The effects of including novel objects in the environment ("environmental enrichment “) on body‐weight gain, relative body‐weight gain, gain : food ratio, plasma growth hormone (GH) and prolactin concentrations in male and female broiler and layer chicks was investigated.

2. Environmental enrichment improved body‐weight gain, relative body‐weight gain and gain: food ratio but had no effect on circulating GH or prolactin concentrations.

3. Weight gain and gain : food ratio were greater in the broilers than in the layer chicks, while plasma GH and prolactin (females only) concentrations were less.

4. There were no sex differences in weight gain and relative weight gain but gain : food ratio was significantly greater in females than in males. In both strains plasma GH concentrations were higher in males than in females and prolactin concentrations were higher in male than in female broilers.     

Compensatory growth after under-nutrition in market turkeys

Five levels of protein were fed from o to 6 weeks of age, resulting in groups of poults whose body weights at 6 weeks were depressed by 8, 25 and 50 per cent below maximum. After 6 weeks, all groups were fed adequate amounts of protein and the undernourished poults showed substantial compensatory growth. The treatment which resulted in a mean body weight 25 per cent below controls at 6 weeks gave only a 3 per cent reduction in live‐weight at 14 weeks of age.

Undernourished poults ate more food at any given live‐weight between 6 and 14 weeks of age than did fully fed controls when they were at the same live‐weight. Food conversion was better in undernourished than in fully fed poults in the 6 to 14 week period even after a correction had been made for differences in the food required to maintain different body weights.

Taking the whole period from o to 14 weeks, there was a small improvement in the efficiency of food conversion and a large increase in the efficiency of protein conversion to body weight in favour of the poults which had been undernourished to 6 weeks of age.     

Comparison of performance and intestinal characteristics of broiler chickens fed on diets containing whole,rolled or ground barley

1. In two experiments, no consistent differences in weight gain or food intake appeared between broiler chickens given diets based on whole or rolled barley, but food: gain ratio and gizzard weight as a percentage of live weight were reduced (P<0.05) when barley was rolled. Grit addition did not affect performance or intestinal characteristics.

2. In a third experiment, whole barley diets gave significandy higher weight gain than ground barley diets; this was attributable to the significandy higher food consumption. Gizzard weight as a percentage of live weight increased (P< 0.05) when whole barley was fed, while foodrgain ratio was not significandy (P>0.05) affected by the form of barley.

3. The number of particles in the intestinal contents with sizes larger than 2.4 mm was not significantly (P<0.05) different between broiler chickens fed on whole barley and those fed ground barley, but the number of particles with sizes between 2.4 and 0.7 mm was lower (P< 0.05) when diets with whole barley were fed.

4. Enzyme addition increased (P< 0.05) weight gain and the DM of intestinal contents, and decreased (P<0.05) intestinal viscosity, food:gain ratio and pancreas weight as a percentage of live weight regardless of form of the barley.     

Divergent selection for residual food intake in Rhode Island Red egg‐laying lines: Gross carcase composition,carcase adiposity and lipid contents of tissues

1. A sample of 48 hens and cockerels from generation 17 of a divergent selection experiment on residual food intake was examined to determine whether the large food intake differences between those lines were associated with differences of body composition.

2. Adiposity and lipid contents of various parts of the carcase were higher in the low residual food intake line than in the high residual food intake line, both in males and females, with the cockerels of the high residual food intake line markedly lean.

3. On an equal weight basis obtained by linear correction for body weight differences, males had heavier thigh, drumstick and bones, but less adipose tissue and smaller amounts of lipids in the liver, meat, skin and abdominal adipose tissue than females.     

Growth,food conversion,carcass yields and their heritabilities in ducks (anas platyrhynchos)

1. Live weight, food consumption, eviscerated carcass weight, breast muscle mass and ratios of these traits were measured in a strain of ducks of known pedigree. Heritabilities, genetic and phenotypic correlations were estimated for all traits. From the results the following conclusions are drawn.

2. Selection for live weight at market age would be simplest and most effective in improving growth rate and food conversion efficiency though would not necessarily markedly improve carcass lean meat.

3. Selection to increase the proportion of breast muscle (heritability (h ² ): 0.55) should be effective but might depress body weight as a correlated response. The effect on fat content is uncertain.

4. Selection for food conversion efficiency (h² : 0.21) might be expected to increase body weight, but its effect on carcass lean meat (proportion of breast muscle) is uncertain.

5. Selection for breast muscle mass (h ² : 0.41) should improve body weight and food conversion efficiency but its effect on proportion of lean meat is much less certain (rG = 0.45 + 0.17).     

Food consumption records for the genetic improvement of income over food costs in laying flocks of white leghorns

1. A study of genetic parameters of egg mass based on the weights of all eggs laid, individual food consumption, body weight and age at first egg was made. Data from three populations differing in average egg weight were available over two production periods, from 20 to 40 and from 40 to 60 weeks of age, respectively.

2. Selection indexes designed to maximise income over food costs (IOFC) were used to evaluate the usefulness of food consumption data for the genetic improvement of laying flocks.

3. Given reliable estimates correlating food consumption to egg mass, body weights and age at first egg it is possible to construct highly efficient selection indexes for genetic improvement of IOFC without the direct use of food consumption data.

4. Selection for genetic gains in egg mass appears to be the most important factor for genetic improvement of IOFC. Correlated increases in egg weight were observed for two of the populations.

5. Body weights showed very small and inconsistent genetic responses under index selection suggesting that a reduction in body weight need not be necessary for more efficient egg production.

6. Indexes which showed greatest genetic improvement also resulted in an increase of food consumption. Thus genetic efficiency in egg laying flocks would be achieved by increasing egg mass through earlier sexual maturity, larger eggs and higher production rates with increased food consumption and only slight, if any, reduction in body size.

7. Estimates of heritabilities and genetic correlations indicate that food consumption measurements can be based on partial records; high heritabilities were found for egg mass and food consumption measurements in both early (20 to 40 weeks) as well as late (40 to 60 weeks) production periods.     

Size of food bowl and scoop affects amount of food owners feed their dogs

The incidence of canine obesity appears to be increasing dramatically and understanding factors impacting the amount of food pet owners provide their dogs may improve weight management. Human research has shown the size of food bowls, plates and utensils can significantly impact the amount of food portioned and consumed. This effect can be attributed to both the Delboeuf optical illusion and the Ebbinghaus-Titchener size-contrast illusion. To investigate the existence of a similar effect with dog owners, 54 dogs and their owners were recruited for a four treatment randomized prospective trial. Owners scooped out a normal kibble-based meal using a small bowl and small scoop, small bowl and large scoop, large bowl and small scoop or a large bowl and large scoop. Each treatment was used once per owner over four visits. Repeated measures anova revealed the mean amount of food portioned using the small bowl and small scoop was significantly less than all other bowl and scoop combinations (150.7 g vs. 171.5 g vs. 172.7 g vs. 184.5 g, p < 0.05). The small bowl and large scoop combination did not differ from large bowl and small scoop (171.5 g vs. 172.7 g, p > 0.05). Owners were more likely to portion a larger amount of food with a large bowl and large scoop. Results are consistent with human data and emphasize the need for owners to use standard measuring cups. Results also suggest owner compliance during weight loss programs may be improved with smaller bowls and serving scoops.     

Effects of diurnally cycling versus constant temperatures on chicken growth and food intake

1. Male broiler chickens were exposed in separate experiments to: (a) constant ambient temperatures (Ta) ranging between 10 and 35°C; (b) 12 h: 12 h diurnal high‐low temperature of 10:30°C, 15:35°G and 15:30°C in different trials; and (c) 12 h of 30 or 35°G and 12 h of variable lower temperature.

2. A progressive decline in weight gain and food intake was obtained as Ta increased from 18 to 35°C. Under diurnally cycling temperature, weight gain and food intake were lower than in the average corresponding constant temperature, with the exception of chickens exposed to 15:30°C, where weight gain and food intake were not significandy different from those of the constant average temperature.

3. As the diurnal cold period was made colder, chickens exposed during half of the diurnal cycle to high temperature (30, 35°C) demonstrated a significant (P ≤ 0.05) increase in weight gain and food intake.

4. There was a good correlation between plasma triiodothyronine (T3) and Ta. The correlation between T3 and food intake was highly significant, but that between T3 and weight gain was poor.

5. The results indicate the difficulties in predicting the performance of broilers exposed to diurnally cycling temperatures from knowledge of the average temperature.     

Thermoregulation and Water Balance as Affected by Water and Food Restrictions in Sudanese Desert Goats Fed Good-quality and Poor-quality Diets

Nine desert goats were used in a 3 x 3 Latin square design in which they were subjected to (a) ad libitum water and food (control), (b) ad libitum food and water restricted to about 40% of the control, and (c) ad libitum water and restricted food (same amount as given to group b). Parameters measured were dry matter intake (DMI), water intake, rectal temperature (Tr), respiration rate (RR), water balance and body weight (BW) changes. The acute effects of the above treatments on these parameters were monitored during the dry summer using two types of feed. The ratio of DMI to water intake decreased (p < 0.01) due to water restriction but increased (p < 0.01) with Lucerne hay compared to grass hay. With both feeds, BW decreased (p < 0.01) with water restriction, with a further decrease (p < 0.01) observed with food restriction. The control group showed a higher (p < 0.01) gain with Lucerne hay than grass hay. Tr and RR increased (p < 0.01) from morning to afternoon; Tr decreased due to food restriction during both morning and afternoon with Lucerne hay (p < 0.05) and grass hay (p < 0.05), whereas RR decreased (p < 0.01) with both types of feeds. For all groups of animals, Tr was higher (p < 0.05) with Lucerne hay than with grass hay, this effect being more pronounced (p < 0.01) with the control group. With both feeds, water restriction decreased (p < 0.01) water turnover rate and evaporative losses, with decreased (p < 0.05) faecal losses observed in the water-restricted groups on Lucerne hay but higher (p < 0.05) losses of urine. The tolerance of desert goats to thermal stress and their coping with shortage of water and food depended on their capacity to lose heat through panting and cutenaous evaporation as well as their ability to concentrate urine.     

Imprecision when using measuring cups to weigh out extruded dry kibbled food

Many pet cats and dogs are fed dry extruded kibbled food by measuring cup, yet the precision and accuracy of this feeding strategy is not known. Over 12 studies, we assessed precision and accuracy of weighing out food portions, of various dry kibbled foods, by measuring cup. Poor precision was noted in all studies, with intra- and inter-subject coefficients of variation ranging from 2 to 13% and 2 to 28% respectively. Variable accuracy was also noted, which ranged from an 18% under-estimate to an 80% over-estimate in portion size. No specific factors were associated with imprecision, but the degree of inaccuracy was negatively associated with portion size (R = -0.67, p = 0.022), and positively associated with the number of subjects participating in the study (R = 0.60, p = 0.048). This is the first study to document imprecision and inaccuracy of using measuring cups to estimate portions of extruded dry kibbled food. Over time, such errors could contribute to insidious weight gain in companion animals, potentially contributing to the development of obesity. Imprecision in measuring food portions could also contribute to failure of weight management programmes for obese animals.     

Selection for efficiency of food utilisation in laying hens: Direct response in residual food consumption and correlated responses in weight gain,egg production and body weight

1. Two‐way selection was performed in a White Leghorn population for percentage residual food consumption, defined as the percentage deviation of the observed from the expected food consumption. Expected food consumption was estimated using a multiple regression equation including weight gain, egg production and metabolic body size as independent variables.

2. Three selection lines were established from a common population, two low lines and one high line. In addition, one control line was kept. The generation interval was one year and the experiment lasted for 4 generations.

3. The direct selection response was considerable and the realised heritability was close to 0.5. Food intake and food conversion (FCR) were lower in the low lines than in the high line.

4. The correlated selection responses showed no phenotypic or genetic correlations between percentage residual food consumption and egg production, but one of the low lines had a heavier adult body weight than the high line. No undesirable correlated responses were observed.