1. Direct and correlated responses were determined after five generations in four lines of chickens selected either for increased body‐weight gain (line W), for increased food consumption (line F), for decreased food conversion ratio (line E), or at random (line C).
2. Realised heritability estimates calculated after five generations of selection were : 0–37 + 0.04 for weight gain (WG); 0.44 + 0.05 for food consumption (FC); 0.21 + 0.04 for food conversion ratio (FCR).
3. Realised genetic correlation estimates were: WG and FC, +0.71 ±006; WG and FCR, ‐0.40±0.09; FC and FCR, +0.27 + 0.09.
4. Zero‐generation heritability and genetic correlation estimates were greater than the realised estimates, and sex linkage appeared to be important in the expression of all three traits.
5. The genetic correlation between FC and FCR was asymmetrical with considerable positive response in FCR in line F (rg = +0.79) but negligible response in FC in line E (rg = —0.01).
6. There was an apparent plateau in response in FCR in line E from the third to the fifth selected generations. 相似文献
1. The decrease in strength of an egg shell which is known to accompany an increase in the period of time over which a load is applied might come about by either of two mechanisms: a decrease in the strength of the material constituting the strong, outer layer of the mineral shell, or a decrease in the thickness of this layer brought about by deepening of the crevices that are normally present between adjacent crystal columns in the weak, inner layer of the shell.
2. Experiments designed to discriminate between these mechanisms are described: the results indicate the second mechanism.
3. This mechanism offers explanations for various other shell phenomena, including delayed fracture under a static, cyclical or recurrent load.
4. The main implication for the poultry industry is that any external insult to a shell is likely to weaken it by doing damage that is local, internal, irreparable and cumulative, even though it may be invisible from the outside. 相似文献
An 11-month-old male Miniature Poodle was found to regurgitate small volumes of fluid and food particles due to a diverticulum in the thoracic oesophagus. The diverticulum was removed surgically. Histologically the wall contained extensive scar tissue. Longterm recovery was uneventful and 5 months after surgery the dog is in good health 相似文献
Summary The first Newcastle disease epidemic in Cyprus was reported in 1949 to 1950 and between 1953 and 1959 there was a second. In November 1977 another Newcastle disease outbreak occurred. Measures implemented immediately were: quarantine of all foci of infection, destruction of diseased and in-contact birds, disinfection of premises and island-wide (Government controlled) vaccination. Within a month the epidemic was brought under control. In all 47 outbreaks were recorded with the loss of about 35,000 birds. Only 2 commercial units were affected, the remaining outbreaks occurring in premises of back-yard poultry keepers. The virus was the Asiatic type.
La Enfermedad De Newcastle En Chipre: Revisión De La Literatura
Resumen La primera epidemia de Newcastle en Chipre se describio en 1949–50 y la segunda entre 1953 y 1959. En Noviembre de 1977 ocurrio otro brote. Las medidas tomadas fueron: cuarentena de todos los focos de infección, destrucción de todas las aves enfermas y en contacto, desinfección de los galpones y vacunación general. La epidemia se controló en un mes. En los 47 brotes diagnosticados, hubo una pérdida calculada de 35 000 aves. La enfermedad se diagnosticó en dos empresas comerciales y en unidades pequeñas familiares. El virus aislado fue el tipo Asiático.
La Maladie De Newcastle A Chypre—Revue
Résumé La première appartition de la maladie de Newcastle à Chypre, a eu lieu en 1949–1950, avec une seconde vague entre 1953 et 1959.La maladie est répparue en 1977. Les mesures assitôt prises ont été: la mise en quarantaine des foyers d'infection, la destruction des animaux malades et des animaux contaminés, la désinfection des locaux et une large vaccination, sous contrôle officiel, des volailles de l'Ile. En l'espace d'un mois la maladie a été enrayée. Pour les 47 foyers constatés les pertes se sont élevées à environ 35 000 têtes. Deux élevages commerciaux ont seulement été atteints, les autres foyers étant apparus dans les poulaillers des petits éleveurs.
The cercariae of Eurytrema pancreaticum (Janson, 1889) possess four types of gland cells - proper cystogenic, penetration, ventral and dorsal gland cells. The secretion of ventral and dorsal gland cells is released into the tegument. The proper cystogenic gland cells are the largest and their contents serve for the formation of the cyst wall of metacercariae in the second intermediate host. The secretion of proper cystogenic gland cells contains besides neutral mucosubstances also acid mucosubstances with both carboxyl- and sulphogroups digestible with beta-glucuronidase. The secretion of penetration gland cells contains neutral mucosubstances and proteins with tyrosine, tryptophan and SS groups. The ventral gland cells contain mostly acid mucosubstances with sulphogroups, which are digested with beta-glucuronidase, and proteins with tyrosine, tryptophan and SH groups. The rudimentary dorsal gland cells contain a small amount of acid mucosubstances. The whole tegument of cercariae and the two main collecting canals of the excretory system exhibit a high alkaline phosphatase activity. The nerve ring and the main nerve truncs contain proteins with SH groups and hydrophilic lipids and exhibit a cholinesterase activity. The suckers contain a larger amount of glycogen. 相似文献
The effect of endotoxin induced fever on the steady state concentration of sulphadimethoxine in pigs has been studied.Sulphadimethoxine 20 mg/kg b.wt. was injected at 9 a.m. in an ear vein each day for eleven days. From day 6 until the end of the experiment, endotoxin fromEscherichia coli 1.5 g/kg b.wt. was injected at 9 a.m. and at 3 p.m. The plasma concentration versus time curves were calculated by means of a computer program, assuming a two-compartment model. During the endotoxin injections the plasma concentrations were simulated and compared with those calculated.It was not possible to show any clinically significant changes in pharmacokinetics of sulphadimethoxine after the start of endotoxin injections. 相似文献
The function and suppression of urine spraying by cats is discussed as also is the source of tom-cat odour. It seems unlikely that tom-cat odour is derived from the lipid in the proximal convoluted tubule of the kidney, however its production by the anal glands has not yet been proven. Although male cats show a flehmen response when sniffing urine, smell seems to play a more important role in reproduction in the female than the male. The available data suggests that valeric acid may function as a female/female pheromone in cats by inducing or facilitating oestrus. Nepetalactone, the active ingredient of catnip, is probably not related to any naturally occurring pheromone in the cat but simply acts as an hallucinogenic drug. 相似文献