Hatching Season Research Articles

Growth of Juvenile Crocodylus porosus as Effected by Season of Hatching

Growth of Juvenile Crocodylus porosus as Effected by Season of Hatching

Sire × hatching season interaction in egg production traits within flocks of domestic fowl

The extent of sire x hatching season interaction in egg production characters has been studied in White Leghorn, Australorp and Synthetic flocks in which half-sib families bred from the same sires were mated largely to the same dams for spring and autumn hatchings. Interaction appeared to be more important in White Leghorn and Synthetic than in Australorp. The estimate of variance component for interaction was not consistent among the three flocks, and it was important only in certain flocks for different characters: age at first egg, part-annual hen-housed production (PHP), and egg weight at 34 and 62 (EWL) weeks of age in Synthetic; and annual survivors' production and egg specific gravity at 62 weeks of age (SGL) in White Leghorn. Comparison of within-season and across-seasons heritabilities showed that the former could be on average more than 45% higher than the latter in PHP, EWL, SGL and annual hen-housed production. As the estimates of the genetic correlation coefficient between seasons tend to be below 1.0 for many characters in White Leghorn and Synthetic, the sire x hatching season interaction may need to be taken into account and investigated further to improve the efficiency of selection for egg production.

Seasonal Variation in the Response of Chicks to Dietary Cholesterol

IN THE routine use of cholesterol-fed White Leghorn cockerels2 for testing hypocholesteremic agents, marked changes in the response of the chicks to dietary cholesterol were observed among groups hatched on various dates (Whiteside et al., 1964). These findings prompted a study of other factors which might be related to season of hatch and response of chicks to dietary cholesterol. PROCEDUREGroups of day-old cockerels were obtained at various intervals from March to October, 1963. The chicks were randomly divided into groups of 10 chicks each and placed in heated battery brooders. Average initial body weight was determined for each group. Groups were supplied ad libitum a diet consisting of 36.2% ground yellow corn, 40% soybean meal (50% protein), 10% coconut oil, 5% corn starch, 3.5% steamed bone meal, 3 % dehydrated alfalfa meal (17% protein), 1% cholesterol, 0.4% iodized salt, 0.35% methionine-hydroxy-analogue,3 and 0.02% manganese sulfate, and supplemented with all…

Breeding ecology of the House Swallow, Hirundo rursica

The House Swallow, Hirundo rustica, first arrives S. Japan in mid. March and the main flock occurs in Honshiu in early April. 2. In Hachioji, Tokyo, the peak of nesting is mid. April, the earliest 31 March. The percent nesting was 8% and the nesting period 8 days. Sixty percent of pairs used the old nests; worked for nesting chiefly during the forenoon and harder they worked for new nest. 3. The peak of laying occured in late April, the earliest the 8th. The clutch size 3-7, with the mean 5, and larger in the first broods. 4. The egg is laid daily between 5-7 a. m. 5. The egg size measured 21×15cm, 1.4g. 6. The peak season of hatching was late May. The incubation period was 14 days for the 1st and 12 days for the 2nd broods; the average brood size at hatching 4.7. 7. The feeding frequency per hour was average 32 times during the for-and 27 times afternoon. 8. The chick's weight was: 3rd day 5g., 6th day 12.5g, 9th day 16.7g. and 15th day 19.4g. The adult weigh 18g. 9. The chicks flew most in mid. June, early example on 20 May. They flew from nest led by a parent on fine day between 10-12 a. m. Average flying brood size 4.5 chicks; the fledging period was 21 days for both 1st and 2nd broods but when counted from the date of the laying of 1st egg, it was 39 days for the 1st and 36 days for the 2nd broods. 10. The percent damage from total of eggs laid was 27%. 11. The banding resulted 9.1% recovery of adults and 1.4% of young birds.

アサリ養殖における有害動物としてのカクレガニの生態-II

The present paper is a record of the ecological observations of Pinnotheres sinensis as pest in culture of Tapes japonica and the influence of the crab on the weight of the host's flesh. It was not observed that two or more female crabs were living in one host. Few male crabs were observed in host and five living with female were found among thirty-seven crabs. One of the writers caught a male crab walking on the outside of the mussels (Mytilus edulis) in the field. The berried crabs were found from July to October, exceptionally in June and December (Fig. 1) but the optimum hatching season ran from September to October at water temperatures ranging from 24°C to 19°C. From next May to July many young crabs were found in the host (Fig. 2) and they became to berry in Autumn. The biological minimum size was 5.3mm in carapace length. Large crabs (over 8mm) began to decrease in number from summer. The size of berried crabs varied in accordance with the period in breeding season. The highly infested region with Pinnotheres sinensis was situated along the channel (Fig. 3). In the laboratory, some female crabs free from the host were possible to live fairly long time viz. 4-6 months. Tapes japonica infested with Pinnotheres sinensis was lean without regard to their size or season (Fig. 4, 5).

Multiple Shifts for Testing Cockerels

DURING the first 8 years of selection at this laboratory for genetic resistance to leucosis combined with other traits of economic value, it was our practice to leave each male in his breeding pen throughout the entire hatching season of 8 to 10 weeks. By 1942 it was evident that, while marked improvement had been made in the first three years, progress thereafter had been almost nil. It was equally clear why improvement had stopped.We had tried each year to find enough good proven sires to head at least 25 percent of the breeding pens. During the first 5 years, the average number of pens used for the two resistant lines together was only 13.2, but, among the 10 cockerels or so tested annually, it was seldom possible to find 3 or 4 proven sires that could be used again without considerable misgivings. In 1940 to 1942, the average …

A Study of Artificial Incubation of Runner Duck Eggs: Requirements

IN SPITE of the growing interest in better and more assured methods of artificial incubation of ducks eggs, the problems of selection of the incubator and the control of environmental conditions for incubation had never been adequately investigated. The present study was undertaken in response to this general sentiment and to the call for a more economical and efficient method of hatching.The main object of the study, therefore, was to determine the effect of the rate of air agitation and to establish the requirements for temperature and humidity in the incubation of duck eggs.METHODS AND MATERIALSThe eggs of White Runner ducks (Anas domesticus) were used. The experiments were conducted during the natural hatching season in the month of April for four consecutive years, from 1936 to 1939, inclusive. There were used 2,630 fresh eggs, which were rigidly selected for the uniformity of shell structure, size, and shape. .