G. Richter

Effect of the manganese content in laying hen feed with different Ca and mineral levels on the egg shell quality and bone mineralization of hens

Four experiments with 270, 44, 432 and 66800 Leghorn hens were carried out to investigate the influence of various Mn additions to diets differed in mineral or Ca contents on egg shell quality. The addition of 300 mg Mn/kg diet improved significantly egg shell breaking strength by 4 N over one year. The supply of 50-500 mg Mn/kg diet for 10-24 weeks of the second half of laying year did not influence the egg shell quality. Addition of mineral mixture or Ca grit to layer rations with adequate or higher Mn levels did not influence egg shell strength. High mineral content in a low manganese diet increased number of cracks by 3%. Strength, weight and ash content of tibia were significantly reduced by feeding a low mineral level. Addition of 50-150 mg Mn per kg low mineral diet normalized partially tibia stability in young hens. It was concluded that supplied dietary Manganese influences calcification positively only in young hens. High levels of Ca did not influence the effects of Mn. 50 mg Mn per kg layers mixture have been considered as an essential supply.

Einfluß von Flavomycin auf die scheinbare Verdaulichkeit der Rohnährstoffe bei Hammeln, Kennzahlen der Pansenfermentation bei Rindern sowie Futteraufnahme und Lebendmassezunahme weiblicher Jungrinder

Three experiments with five wether each were carried out in order to investigate the influence of various levels of flavomycin (0, 5 and 10 mg per animal and day) on apparent digestibility of artificially dried grass. A short time individual feeding experiment (42 days) with 9 bulls and a long term individual feeding experiment (225 days) with 52 heifers were conducted. Animals consumed 0 or 30 mg flavomycin per day. Parameters of rumen fermentation were investigated. Feed intake and weight gain were measured in the experiment with heifers. Flavomycin did not significantly influence the apparent digestibility of organic matter and crude nutrients as well as parameters of rumen fermentation. Flavomycin did not influence dry matter intake, but increased significantly weight gain (49 g per animal and day, 10.5%) and reduced feed and energy required per kg weight gain (10.6%) in heifers. The reasons of ergotropic effects of flavomycin are mostly unknown at present.

Untersuchungen zum Einsatz des Pansenfermoregulators „Monensin“ in der Mastbullenfütterung

In two digestion experiments with wethers and seven feeding experiments with 198 fattening bulls with rations rich in (greater than 55% of the dry matter intake from roughage), the influence of the antibiotic monensin on the digestibility of the ration, on rumen-physiologic characteristic values and on fattening and slaughtering results was investigated. The digestibility of the organic matter and the crude nutrients was not significantly influenced by the use of monensin (20 mg/kg dry matter). The administration of 200 mg monensin per fattening bull and day resulted in an increase of the molar concentration of propionate in the rumen fluid by 9.7 mol%, the concentration of acetate and butyrate decreased by 7.3 resp. 2.8 mol %. On an average of the seven experiments the intake of dry matter was diminished by 5.1% through the use of monensin, the live weight increase remained almost unaffected (3.0% additional increase), feed and energy requirement per kg live weight were improved by 7.9%. The fattening results do not always correspond in the various experiments. The results of the dressing of the carcass, the composition of the carcass and the quality of the meat remained unaffected by the administration of monensin.

Rapeseed and rapeseed meal as components in diets of laying hens

In an experiment with 405 Hisex white hens rations with 5-20% low glucosinolate rapeseed (RS) or rapeseed meal (RSM) of 00 quality were used. Feed intake, egg production, individual egg weight and live weight gain were reduced in hens fed 5-20% RS and 10-20% RSM. There was a positive correlation between the RS proportion in the ration and the thyroid weight as well as the iodine content of the thyroid. The relation between the iodine content related to one gram of thyroid and the RS proportion was not significant. There were not any significant differences between the RSM groups and the iodine content of the thyroid. The T3 and T4 concentrations in the blood plasma was independent of the RS- or RSM-proportion in the diet. The outward egg quality was not influenced by feeding. The Haugh units were lower when RS or RSM were offered. The fatty acid pattern of the yolk was changed by RS or RSM feeding, particularly the proportion of oleic acid increased. We concluded from the results, RS cannot be recommended for feeding white hens and only a maximum of 5% RSM should be administered.

Untersuchungen zum Vitamin-E-Bedarf der Legehenne

: In 5 experiments with 1,296 laying hybrids at the age of 22-73 weeks producing eggs for consumption a varied supplementation of between 0 and 20 mg vitamin E per kg of a semisynthetic ration was tested. The vitamin E content of the basal ration was less than 1 mg per kg feed. The quotas of selenium and unsaturated fatty acids in the feed were taken into consideration. Vitamin E and Se supplements did not influence, feed intake, laying, performance, feed efficiency/100 g egg development of body weight and mortality. The supplementation of 14% vitamin-E-free sunflower oil caused a significant decrease of the laying performance by 15%. There was no relation between the humoral immune reaction and vitamin E supply. The peroxide value of the abdominal fat and the activities of the creatine phosphokinase, the aspartate and alanine amino transferase in the blood serum were not directionally changed by the vitamin E, Se and oil supplements. There were no significant relations between the vitamin E content of the feed and that of the yolk and the yolk sac of the chicken. A vitamin E requirement of less than 1 mg and a requirement norm, including a safety margin, of 5 mg per kg feed was derived from the results for laying hens for egg production. A supplement of synthetic vitamin E to laying hen feed is thus not necessary.

Beziehungen zwischen der Vitamin-E-Versorgung und der Fruchtbarkeit der Legehennen

: In 4 experiments with a total of 1296 laying hens it was ascertained that a laying hen requires 1 mg vitamin E/kg feed for egg production if the ration contains sufficient selenium and is not rich in multiply unsaturated fatty acids. For the fertilization of the eggs little more of this vitamin is required. There were close relations, however, between the amount of vitamin E supplement to the feed and the number of hatched chickens in % of the fertilized eggs. With the help of the experiments carried out so far the exact requirement could not yet be ascertained. Based on the results of our experiments we recommend 20 mg vitamin E/kg feed for breeding hens of the laying variant. There is a close relation between the vitamin E content of the feed and that of the yolk. A supplement of 7 or 14% resp. of vitamin-free sunflower oil decreases -in dependence on the vitamin E supplement-hatching in particular without diminishing the vitamin E content of the yolk. The vitamin E content of the yolk sac, however, was drastically reduced. The influence of polyene fatty acids in hatching is smaller when sunflower oil rich in vitamin E is supplemented. Vitamin-free sunflower oil has an influence on the vitamin content of the yolk, but it diminishes drastically the vitamin content of the yolk sac and, provided that vitamin E supply is low, prevents hatching.

Prüfung von Legehennenfutter mit varüerter Vitamin-E-und Antioxydans-Supplementation

: In two experiments with 1,250 laying hybrids the influence of the elimination of vitamin E and antioxidant supplements to the laying hen feed was tested. With mixed feed according to official quality requirements but without vitamin E and antioxidant supplements laying hens achieved the same laying performance and individual weight as the control group. There was no influence on feed consumption, feed expenditure per 100 g egg, mortality, development of body weight, the tensile strength of the eggs and the fat quality of the body either. Vitamin E content in the yolk increases with the growing vitamin E content in the feed. The vitamin E requirement norm of laying hens for consumer egg production is achieved at a native vitamin E content of 7 mg/kg laying hen feed. The supplement of synthetic antioxidant is unnecessary.

Untersuchungen zum Einfluß von Avoparcin auf scheinbare Verdaulichkeit, Kennzahlen der Pansenfermentation sowie Mast- und Schlachtleistung wachsender Hinder

Four digestion experiments with 5 wethers each (0, 15, 30 or 60 mg avoparcin per animal and day), three individual feeding experiments (28, 18 or 56 bulls per experiment; 0 and 150/200; 0, 250 and 500 or 0 and 200 mg avoparcin per animal and day in the experiments 1, 2 or 3) and two group feeding experiments (60 bulls and 161 heifers per experiment; salt lick stones without or with 2.5 g avoparcin per kg) were carried out in order to investigate the influence of avoparcin on apparent digestibility, figures of rumen fermentation, fattening and slaughtering results as well as protein, fat and energy retention. Avoparcin supplementation did not significantly influence the apparent digestibility of organic matter and crude nutrients. Concentration of acetate of rumen liquid was decreased (16 or 36) and that of propionate was increased (25 or 50 mmoles per mol) when 200 or 500 mg avoparcin per animal and day were added. Acetate:propionate ratio decreased from 4.2 to 3.5 and 3.1:1. Avoparcin did not influence feed intake, enhanced daily weight gain (37 to 174 g per animal and day) and improved feed efficiency (5 to 26%). Salt lick stones with avoparcin increased weight gain (58 and 96 g per animal and day). Slaughtering results and body composition of bulls were not influenced by avoparcin. Daily retention of protein, fat and energy was significantly increased (16 to 18%; P less than 0.05) when avoparcin was supplemented.

Untersuchungen zur Vitamin-A-Versorgung der Legehennen einschließlich Aufzucht

In seven experiments with 46,310 young animals from hatching to the 21st week the vitamin A supplement varied between 0 and 10,000 IU per kg mixed feed. Feed intake was significantly diminished in three out of seven experiments when chicken feed was given without vitamin A supplement. In the young chicken period 1,500 IU vitamin A supplement were sufficient for optimal body weight development, in the young hen period native carotene was sufficient. The variation of the body weight of the individual animals on the 126th day did not show any connection with vitamin A supply. The carotene content of the rations was sufficient to prevent deficiency symptoms. The livers and yolk sacs of one-day-old chickens on average contained 114 and 56 IU vitamin A/g substance when the parents had received mixed feed with 15,000 IU vitamin A/kg. There is a positive relation between the vitamin A supply of the young chickens and hens and the vitamin A content of the liver.

Influence of dietary niacin on volatile fatty acids in rumen liquid of sheep and rumen dry matter degradability of untreated and ammonia-treated wheat straw

Three rumen fistulated sheep were fed with roughage (1200 g artificially dried grass) or a concentrate/roughage diet (600 g concentrate, 400 g artificially dried grass per animal and day). The diets were unsupplemented or 0.5, 1 and 2 g niacin per animal and day were added. After a 14-day adaptation period samples of rumen liquid were taken 0, 1, 2, 3, 4 and 6 h after morning feeding. In a second experiment untreated and NH3-treated wheat straw were incubated in nylon bags for 6, 12, 24, 48 and 72 h in the rumen of 5 sheep fed with 1.2 kg artificially dried grass and unsupplemented or supplemented with 1 g niacin per day. Niacin did not significantly influence the total concentration of volatile fatty acids, acetate and branched chain fatty acids in both types of diet (P less than 0.05). 0.5 and 1 g niacin in the roughage and 0.5 g niacin in concentrate/roughage diet increased the propionic acid concentration and reduced the butyric acid concentration in rumen liquid of sheep (P less than 0.05). Niacin resulted in a small decrease (P greater than 0.05) of dry matter degradability in rumen. After 48 h incubation time, the dry matter disappearance of untreated and NH3-treated wheat straw amounted to 35.4 and 46.2% resp. The effects of niacin on rumen fermentation may be useful in avoiding ketogenic situations in dairy cows.