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1. The effectiveness of selection of broiler breeder males for body weight at 3 weeks of age on later growth, semen quality and performance of progeny has been tested.2. Correlation between 3- and 20-week body weights in the breeders was poor but significant.3. On the basis of 3-week body weight males were divided into heavy birds (mean+ 0.5 standard deviation) and all birds.4. Semen quality was not different between the two groups, but some selection for semen quality was practised within groups.5. There were no differences in fertility and hatchability of eggs produced from hens artificially inseminated with diluted, stored semen from both groups.6. There was a small, positive, but non-significant, effect of selection of breeder males on body weight of progeny at 6 weeks of age.

Semen from commercial broiler breeder males was diluted two-fold and stored for 6 and 24 h at 2 to 3 °C. For each storage period, groups of caged dwarf broiler breeder hens from the same strain were inseminated with 300, 200 or 100 × 106 spermatozoa. Three replicates of 15 birds were inseminated per treatment. Control hens were inseminated with 150 × 106 fresh, undiluted spermatozoa. Inseminations were performed for 5 consecutive weeks during a first (32 to 36 weeks of age) and for 6 consecutive weeks during a second experimental period (42 to 47 weeks). During weeks 33 to 36 of the first period, only 24 h storage and 100 × 106 spermatozoa produced lower (P < 0·05) hatchability of all eggs set than the control (84·4 compared to 88·6%). During weeks 43 to 47 of the second period, no significant differences between treatments were observed. Embryonic mortality, measured at different periods during incubation, was not affected by the storage time or the number of spermatozoa inseminated.

1. The turkey industry is moving towards the development of stud farms, but an essential condition is the existence of efficient methods to store the semen.2. Much research has been done recently to determine the number of viable spermatozoa in an insemination dose needed for maintaining optimum fertility. Practical methods to determine the number of intact spermatozoa in semen, both before and after storage, are under development.3. It is now possible to store turkey semen for 6 to 24 h without appreciable loss in fertility and hatchability. Ideal experimental conditions for 48 h storage have not yet been fully determined.4. Development of new storage media, allowing the insemination of very low numbers of spermatozoa, may provide interesting possibilities regarding the use of elite sires.

1. Semen of White Leghorn and Rhode Island Red males was stored for 24 h in diluents hypertonic (460 mOsm/kg H2O) and isotonic (340 mOsm/kg H2O) to cock seminal plasma.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.

Semen obtained from Rhode Island Red males was stored for 3 and 24 h in fresh and freeze-dried diluent. Fertility and hatchability of eggs laid from the 2nd to 8th d inclusive after a single insemination was tested with hens of proven fertility. The fertilising power of diluted semen after storage did not differ significantly from the undiluted control, but the hatchability of the fertile eggs was significantly reduced after 24 h storage in the freeze-dried diluent.