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61.
62.
1. The growing embryo uses about 1% of the total protein available in the egg during the first week of incubation.

2. Injecting the growing embryo with amino acids equivalent to the amount of protein used resulted in higher weight of chicks at all stages up to 56 d.  相似文献   

63.
1. An experiment was done under commercial conditions to investigate the physiological effects of isolating broody turkey hens, for 72 h, in sand and wire floored pens on the third, 10th and 16th weeks of production.

2. Hens identified as broody and removed from the flock had higher plasma prolactin concentrations than the laying hens at each of the three experimental stages.

3. Confinement in sand and wire floored pens, induced a decline in plasma prolactin concentrations. This decline probably impeded immediate development of broody behaviour. Alternately, levels of prolactin higher than those of laying hens were again measured 7 and 14 days after treatment during third week but not after the 10 th and 16th week of production.

4. Confinement did not induce consistent changes in luteinising hormone (LH) and progesterone concentrations from one period to an other.

5. An increase in the plasma concentration of D‐(/?)‐hydroxybutyrate was observed in the hens which had an egg present in the oviduct on day 2, 3 and/or 4 of the treatment. Subsequently, a decrease in ovulation rate was observed in the hens with higher concentrations of D‐(β)‐hydroxybutyrate while under treatment, during the 10th week of production.

6. These data confirm that the effectiveness of the traditional methods for broodiness prevention under commercial conditions is related to the induction of a decrease of prolactin.  相似文献   

64.
Since the beginning of year 1987, the deer "Rusa" breeding has been developing in New Caledonia. In 1988, during a slaughter operation amidst the herds, nearly ninety blood samples were collected in order to define the blood biological parameters (or constants) of this species. Regarding haematology, the study concerns the following parameters: erythrocyte count (9.32 x 10(12)/l), leucocyte count (4.51 x 10(9)/l), various leucocyte lines and their formula, i.e. (neutrophile polymorphonuclear: 2.08 x 10(9)/l [46.6 p. 100]; lymphocytes: 1.75 x 10(9)/l [38.4 p. 100]; monocytes: 0.33 x 10(9)/l [7.5 p. 100]; eosinophiles polymorphonuclear leucocytes: 0.4 x 10(9)/l [7.46 p. 100]; basophile polymorphonuclear leucocytes: 0.01 x 10(9)/l [0.28 p. 100]), hematocrite (36.8 l/l), hemoglobin ratio (14.1 g/dl), mean corpuscular volume (40.3 dl), mean corpuscular hemoglobin rate (15.3 pg/cell), mean corpuscular hemoglobin concentration (38.7 g/dl). In the course of the study, variations of these parameters were detected according to various physiological criteria and to the sampling conditions as deer is a stress sensitive animal.  相似文献   
65.
1. Under summer conditions in north Iraq, 2 000 chicks were reared for 56 d in two broiler houses. One house was provided with two air‐coolers. The birds were housed at densities of eight to 16 birds/m2.

2. Differences in weight gain between birds in cooled and uncooled houses ranged from 101.5 g at eight birds/m2 to 385 g at 16 birds/m2. Food consumption increased gradually with increasing bird density. Food conversion efficiency, meat yield and carcass conformation were much better in the cooled house than under conventional conditions.

3. The financial return/m2 ranged from 2.30 to 4.51 ID1 in the cooled house, compared with 2.01 to 2.77 ID in the uncooled house at different floor densities.  相似文献   

66.
1. Whole broilers and separated legs were stored at ‐12 ± 1 °C, —18 ± 1 °C and — 75 ±2 °C (reference group, whole carcasses only), for up to nine months.

2. Legs cut from the whole birds after removal from store, unpacking and thawing, and legs from the portions were compared in odour preference at four times of examination.

3. After only 1 d the odour of the legs stored as parts at —12 °C was less preferred than that of the reference group; this was also true for legs cut from whole birds after 3 months at the same temperature.

4. After 3 months at — 12 °C the odour of the legs stored as parts was less preferred than the odour of legs obtained from whole birds.

5. Storage of legs as parts at —18 °C resulted in a comparatively less preferred odour after 3 months, while the same was true after 9 months for legs cut from the carcasses.  相似文献   

67.
1. Certain rapeseed meals in the diet of hens laying brown eggs result in the production, from some birds, of eggs which have a “ fishy ” or “ crabby ” odour because of the presence of trimethylamine.

2. Such susceptible birds have been used to demonstrate that the activity can be extracted from rapeseed meal with appropriate solvents.  相似文献   

68.
1. The role of certain fish meals in the production of localised gizzard erosion is confirmed.

2. Lesions typical of gizzard erosion could be produced by the addition of histamine to the diet.

3. The amount of histamine occurring naturally in fish meal depends on the species of fish and the extent and nature of bacterial spoilage.

4. These variables may explain why histamine has not been implicated previously and also why there have not been consistent associations between the condition and geographical source or common factors in bulk consignments of the meal.  相似文献   

69.
王娟  王倩  陈清 《中国蔬菜》2005,(B10):32-35
结球莴苣烧边病是生理性病害,严重影响其品质,制约生产。国内外多数研究者认为钙缺乏导致结球莴苣烧边病的发生,但是现在许多研究表明其他因素也能导致烧边病的出现,例如环境因素、生长速率、内源激素等,所以研究烧边病发生的机制及其与环境因素的关系是防御结球莴苣烧边病发生的关键。  相似文献   
70.
Hormonal asynchronies during oestrus, related to the presence of suprabasal plasma-progesterone (P4) concentrations and a delayed ovulation, interfere with the fertility of repeat-breeder heifers (RBH). Since tubal dysfunction can occur in connection with hormonal asynchronies and constrained availability of fertile spermatozoa at the time of ovulation, the present study tested the hypothesis that frequent sperm deposition from onset of oestrus to ovulation may improve pregnancy rates in RBH. Five RBH and five virgin heifers (VH; controls) were repeatedly artificially inseminated (AI) at 6 h intervals from onset of oestrus to spontaneous ovulation. Hormone analyses revealed suprabasal P4 concentrations and a delay in the occurrence of the luteinising hormone (LH) surge, but a normal cortisol profile in RBH. Compared with controls, RBH presented longer interval from onset of oestrus to ovulation, and therefore, received more AIs. Pregnancy rates in RBH reached control levels (60%; NS), indicating that the hypothesis might be correct. Pregnancy rates in VH were below the expected range, presumably attributed to a deleterious influence of the frequent handling. The study suggests that pregnancy rates can be improved in RBH by frequent AI in relation to spontaneous ovulation. However, this practice of repeated manipulations, while seeming not to show adverse effects, lacks practicality for routine use.  相似文献   
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