This first series was carried out over a period of twelve months and beyond. Beginning of fertility. - The literature review mentioned the reasons why the time of insemination affects the length of the period between insemination and the deposition of the first fertilized egg. Fertility of eggs laid four days after intraperitoneal insemination at different hours of the day (all cases with eggs laid within four days.
Chart K shows the incidence of different periods per day between intraperitoneal inseminations in the first series and the laying of the last fertile egg. In one case, fertility was confirmed but the duration of the fertile period was not recorded (insemination no. 18). In the 9th row I; the in~idenc_e of each of the different numbers of eggs fertilized by a mtrapentoneal msemission for the same forty-six (46) cases is shown.
Although the bottom was not of the same intensity of egg production in the cases used to compile the K and L graphs, the number of fertilized eggs is naturally highly correlated with the length of the fertile period. This is shown in chart M by giving the number of times each of the fertile periods (number of days) coincides with each of the numbers of fertilized eggs from an intraperitoneal insemination. iii) (i) rate, (ii) intensity or (iii) consistency of fertility.—In poultry it is necessary to consider (i) whether all eggs laid between insemination and laying of the last fertile egg are fertile, ( ii) whether eggs laid during long fertile periods are as likely to be fertile as eggs laid during shorter periods, and (iii) whether eggs laid later in the period are equally likely to be fertile fertilized than those laid earlier. The database collected is the number of eggs laid on each of the days related to the day of insemination and the number of those that proved fertile.
The percentage of fertility in the first half of the fertile period, compared to that of the second half. However, the maximum length of the period of fertility can be considered very encouraging. The percentage of fertile eggs laid between the time of insemination and collection of the last egg that appears to be fertile (see table 24) is very similar for the different methods of insemination.
However, different lengths of fertile periods after intraperitoneal insemination did not show a different percentage of fertility, which had any relation to the length of the fertile period (Table 25). The difference between the percentage fertility in the first and second half of the fertile period was significantly smaller with intraperitoneal insemination than in the controls (table 26). This is shown by the fact that the average duration of the fertile period was in almost equal proportion to the number of eggs laid during that period in both groups.
For the number of fertilized eggs (222), it should be noted that a single questionable result (insemination no. 45) was omitted. Given the average hatching duration (8·07), one fecundity case that was replaced before the end of the fertile period (insemination no. 18) was not used in the calculations. Occurrence of different periods of hatching duration in days after intraperitoneal insemination.
Broiler chicks hatched after intraperitoneal insemination in a manner that showed no complete conformity with the rules established for naturally mated hens, for example: the slight decrease in percent hatchability towards the end of the fertile period (Crew, 1926; Barfurth, 1896; Nalbandov and Card, 1942).
C. VAN DRIMMELEN
The other figures provide evidence that environmental factors had no unusual influence on egg production after intraperitoneal insemination in the fowl. The small differences in percentages should not be explained solely by differences in the duration of hatching or in the duration of the fertile period, as it has been a consistent experience throughout the work that when considering factors affecting only the chicken influence, groups with lower fertility rates showed a compensatory higher hatch rate. The hatching percentage of eggs from groups with lower percentages of fertile eggs must be due to the properties present in the egg when the eggs were laid.
Observations in the present work are limited to domestic pigeons and chickens, and the following characteristics have been taken into account:-. iii) Production record: -Interval since last previous egg laying. iv) Records of previous inseminations to which the birds were exposed: - Number of previous intraperitoneal inseminations:. iv) Production records: - Percentage of production (ie number of eggs expressed as a percentage of the number of days in the period in which the eggs were collected) for ten days before the day of insemination:. v) Records of the previous insemination to which the birds were exposed: - Interval since the last previous insemination performed on the birds: -. ii) other insemination methods performed within 48 hours. iii). Effect of some subject traits on egg production in laying hens after intraperitoneal insemination. Birds having the characteristics shown in the list and given in the first column of Table 36 are compared for egg production in this table.
The effect on fertility after intraperitoneal insemination due to the same characteristics of the hen appears from the figures in Table 37. Discussion.-Age, recent previous production of eggs and previous inseminations in pigeons showed no detectable effects on the results of intraperitoneal insemination (Table 35), but in chickens some differences were found:-. Breed.- Birds of the "heavy" breeds gave a better percentage of fecundity [Table 37 (33 per cent)] and a longer duration of the fertile period (12 · 7 days) and of hatchability (9 · 4 days), but the lower the fertility in hens of "light" breeds was to some extent compensated by a greater number of chicks obtained per dozen fertile eggs. light breeds) against 43 per cent. heavy breeds) hatchability of eggs laid within ten days of insemination].
The effect of some characteristics of the inseminated individual on the fertility after intraperitoneal insemination of chickens. The effect of some characteristics of the inseminated broilers on hatchability after intraperitoneal insemination. Age.- 2nd year hens outperformed hens in terms of number of intraperitoneal inseminations followed by fertility (12 out of 16) and showed a higher percentage of fecundity [Table 37 (45 per cent)], but hens showed a better percent hatchability [Table 38, (59 per cent)] and a longer average fecundity (10·8 days) and hatchability (8·1 days).
Previous inseminations.-This did not affect the results of intra-peritoneal insemination in the hen, except that the duration of fecundity and hatchability was longest in the groups subjected to others. However, in the case of intraperitoneal operations with simultaneous inseminations by other methods (line i), better percentages of fertility and hatchability were recorded than with such inseminations done ten to two days before (line k). 8) The influence of technique, equipment and material used on the results of intraperitoneal insemination. In view of the small amount of data obtained in the work on pigeons, only the observations made on chickens will be included in this analysis.
The following aspects can be considered:-. a) The size, shape and construction of the instruments of insemination. These aspects will now be considered in order:. a) The size, shape and construction of the instruments used in 117 consecutive cases of intraperitoneal insemination.-Insemination operations were performed with a variety of instruments, including four different commercial syringes and a specially made glass insemination syringe, plus ' n number of different metal needles: -. i).
