Feed intake

Lipids present in the diet may become rancid. When fed at high (>4-6%) levels, Hpids may decrease diet acceptabiUty, increase handling problems, result in poor pellet quaUty, cause diarrhea, reduce feed intake, and decrease fiber digestion in the mmen (5). To alleviate the fiber digestion problem, calcium soaps or prilled free fatty acids have been developed to escape mminal fermentation. These fatty acids then are available for absorption from the small intestine (5). Feeding whole oilseeds also has alleviated some of the problems caused by feeding Hpids. A detailed discussion of Hpid metaboHsm by mminants can be found (16). 

Growth Performance Response. The consistent net effect of anaboHc steroid implant use in growing mminants appears to be increased rate of protein and Hve weight gain, and increased Hve weight at which carcass or empty body fat concentration equals that in nonimplanted cattie thus increasing their potential mature size. Increased feed intake is frequentiy observed. 

The more variable responses with growing catde appear to result from lower doses, nutritional constraints, or lesser responsiveness of younger animals, ie, veal calves. A dose-dependent reduction in feed intake in finishing cattle, which also reduced average daily gain, has been observed (84). However, carcass composition was improved in a dose-dependent manner. 

Animal Nutrition. Sulfur in the diets of mminant animals is beneficial to the animals growth (see Eeedsand FEED ADDITIVES). Sulfur increases feed intake, cellulose and dry matter digestion, and the synthesis of microbial protein. This results in increased meat, milk, and wool production (43). The special uses for sulfur in agriculture demonstrate a significant and continuing need for increased use of sulfur (44). 

Additionally, at very high temperatures, above 30°C, there was a 50% depression in feed intake compared with a controlled environment of 20°C. Although the piglets had access to creep feed, they did not compensate for a probable decrease in milk supply by eating more creep feed. Thus the weaning weight of the litter decreased by about 10 kg when animals were kept at 30°C rather than 18°C (Close, 1990). 

Blummel M, Orskov ER. Comparison of gas production and nylon bag degradability of roughages in predicting feed intake in cattle. Animal Feed Science and Technology. 1993 40 109-119. 

Hyun Y, Ellis M and Johnson R W (1998a), Effects of feeder type, space allowance, and mixing on the growth performance and feed intake pattern of growing pigs , J Anim Sci, 76, 2771-2778. 

Valderrabano, J., Delta, R. and Uriarte, J. (2002). Effect of level of feed intake on the development of gastrointestinal parasitism in growing lambs . Veterinary Parasitology, 104, 327-338. 

Hens started to molt and ceased laying. Feed intake decreased about 90%. Zinc concentrations in pancreas increased 7-fold, in liver 6-fold, kidney 3-fold, and were elevated in shell gland and yolk. High Zn levels in kidney reflect high Zn excretion rates high pancreatic Zn (410 mg Zn/kg FW) may suppress the release of insulin by calmodulin inhibition, and could account for the rapid cessation of lay (Verheyen etal. 1990). 

Cessation of egg laying in all treatments. On resumption of egg production, zinc levels in albumin or eggshell were not affected by the treatment or strain Zn levels in yolk increased and depended on feed intake rather than dose. No increase in zinc content in eggs laid after egg production resumed, regardless of dose or duration of zinc treatment (Decuypere et al. 1988). 

The 1000 mg/kg supplement had no adverse effects on milk production, feed intake, body weight, general health, or reproduction there was a moderate increase in Zn content of plasma and milk. Cows fed the 2000 mg Zn/kg diet, however, had decreased milk yield and feed intake after several weeks calf weights were lower adverse effects reversed when excess zinc was removed from diet. 

No effect on milk production, feed intake, body weight, lymphocyte function, or histopathology of spleen, thymus, or lymph nodes. Postmortem examination showed enlarged liver, lungs, kidneys, and adrenals significant loss of renal function (Forsell etal. 1981 Kinzell etal. 1981)... 

Mice were weighed on a weekly basis. Urine was collected in acid-washed containers for each seven days. Feces were collected daily and composited weekly. The animals were fed daily and feed intake was determined weekly by differential weighing. Glass-distilled water was given ad libitum. 

Feed Consumption. Feed consumption can be measured over two to three consecutive days, and the average daily intake calculated. A problem with measuring feed intake in ferrets is their tendency to dig through their feed bowl, which often results in an unacceptable amount of spillage. Use of a feed follower may help reduce the spillage. 

In a 3-week study in which disulfoton was applied to the shorn, unabraded skin of rabbits and left for 6 hours, 5 days/week, little or no feed intake and distinct weight loss occurred up to the time of death in the rabbits that died within 2 weeks during treatment. Necropsy of the rabbits treated with the high dose of 6.5 mg/kg/day (100%) (Flucke 1986). No effects on body weight were found in rabbits similarly treated with <1.6 mg/kg/day for 3 weeks. 

In the Guidance Notes for Analysis and Evaluation of Repeat-Dose Toxicity Studies (OECD 2000b), OECD provides standard values for body weight, daily feed intake, and conversion factors which allow the conversion of the concentration of a substance in the feed, expressed as ppm or mg/kg, into a dose, expressed as mg/kg body weight per day. These values originally derive from Lehrman (1954 - cited in WHO/IPCS 1987) and have previously been published by the WHO (WHO/IPCS 1987). 

The figures in the column are the factors, which the feed intake (expressed as ppm or mg/kg) should be multiplied with in order to obtain the dose (expressed as mg/kg body weight per day). For example, for a rat (weight 400 g), 1 ppm in the feed is equivalent to 0.05 mg/kg body weight... 

The OECD states, as also outlined in the Environmental Health Criteria Monograph No. 104 (WHO/IPCS 1990), if dietary intake is measured, then JMPR evaluations indicate that X ppm (mg/kg) in feed is equal to Y mg/kg body weight per day but if there is inadequate feed intake data and the tabulated conversion factors are used, then it is reported that X ppm (mg/kg) in the feed is equivalent to Y mg/kg body weight per day. 

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