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2. Compared with the fertility results with semen that had been stored in the hypertonic diluent or was fresh, the fertility of the White Leghorns was not affected after storage in the isotonic diluent; a decrease (P < 0.lb05) was observed, however, using Rhode Island Red semen and isotonic diluent.
3. Fresh RIR semen contained 2.lb31% “neck‐bent spermatozoa” (NBS) which was increased to 4.lb23% and 5.lb76% after dilution in hypertonic and isotonic diluents respectively and stored for 24 h. It is doubtful whether this increase (P < 0.lb05) is the sole reason for the lowered fertility obtained with this breed after storage in the isotonic diluent. 相似文献
2. In a period of sexual quiescence on short photoperiods (6L : 18D) LH concentrations were higher during the hours of darkness in both sexes.
3. Transfer to long photoperiods (16L : 8D) stimulated a rapid increase in LH and FSH concentrations. This was maintained for between 2 to 3 months when the concentrations of both gonadotrophins decreased as the birds became photorefractory.
4. Return to short photoperiods had no immediate effect on the concentrations of LH and FSH in females. The concentration of LH was increased during the 3rd week of short photoperiods when the hens were moulting.
5. LH concentrations fluctuated during the ovulatory cycle and were highest about 6 h before ovulation. 相似文献
2. Chemical tests indicated 72.5% of the total lysine in HFM was available.
3. Total lysine concentration of 11.3 g/kg diet maximised performance during the period 0 to 34 d.
4. Reduction in dietary methionine content during the period 0 to 34 d from 4.2 g/kg to 3.2 g/kg did not depress performance on diets containing 60 g HFM/kg.
5. The results indicate that at least 57% by weight of the total sulphur amino acid requirement of broilers can be provided by cystine. 相似文献
2. At lower speeds down to 2 μm/s Ef is constant.
3. Ef is reduced if the flat plate is replaced by a sphere or cylinder; the greater its curvature, the smaller Ef.
4. Ef for the narrow pole is greater and for the broad pole smaller than that for the equator but these differences may be due in part to . systematic differences in shell thickness as well as curvature. 相似文献
2. When this treated meal was fed to susceptible ("tainting") hens the concentration of trimethylamine in the eggs was decreased to much less than that required to cause taint. 相似文献