Effect of Strain and Time of Oviposition on Egg Shape and Amount of Shell in Turkeys

Abstract

Time of oviposition was recorded for eggs laid by several strains of turkeys involved in genetic studies. A maximum of three eggs per hen was collected at the beginning of lay (Period 1) and during the 15th and 16th weeks of production (Period 2). The shape, weight, and shell quality of all eggs were measured.Egg weight increased from Period 1 to Period 2, but the strains differed in the magnitude of the change. Selection for increased egg production reduced egg weight. The eggs were more round in Period 2 than in Period 1, but there was an interaction between strain and period. Specific gravity was lower in Period 2 than in Period 1 and in the heavy weight strains than in the medium weight strains.Oviposition time did not have a major influence on shape or specific gravity. There was no significant difference in these traits between eggs laid in the morning and those laid in the afternoon. The weight of eggs laid in the afternoon was less than those laid in the morning. (

Pineal Gland and Ocular Influences on Turkey Breeder Hens

“…Essentially all body weight loss of in-season hens occurs within the first 10 weeks of egg laying. Thereafter body weight changes little and is accompanied by decreasing egg production and increasing feed intake (Cherms et al, 1976;Robel, 1981;Bacon and Nestor, 1982). A similar response was observed in the present study.…”

“…The cause of this response is not known but in all likelihood is related to decreased feed intake at the start of egg laying (Cherms et al, 1976). As pointed out by Bacon and Nestor (1982) this response seems to be related to warm environmental temperature and in cool weather (off-season) hens may gain weight during the reproductive period. Essentially all body weight loss of in-season hens occurs within the first 10 weeks of egg laying.…”

“…In-season turkey breeder hens show a characteristic decrease in body weight during their first year of egg production that may amount to 10% of their weight at the start of egg laying (Cherms Bacon and Nestor, 1982). The cause of this response is not known but in all likelihood is related to decreased feed intake at the start of egg laying (Cherms et al, 1976).…”

“…However, a pineal substance (5-methoxytryptophol) was reported to decrease follicular mass of the largest 528 at University of Nebraka-Lincoln Libraries on April 11, 2015 http://ps.oxfordjournals.org/ Downloaded from follicles in the ovaries of chickens (Balemens et al, 1977). Turkey egg weight is influenced by many external and internal factors including the rate of lay and time of lay (Nestor and Bacon, 1982). Melatonin can influence the time of lay in quail (Homma et al, 1966) and chickens (Liou and Biellier, 1983), but PX, blinding, or both has not been demonstrated to influence the rate of lay in quail or chickens (Harrison, 1972;Siopes and Wilson, 1974) or oviposition times in chickens and quail (Harrison and Becker, 1969;Siopes, 1972).…”

Effect of Light Quality on Erratic Egg Laying of Caged Turkey Hens

“…Thus, as observed, both eggs should have reduced shell quality but to different degrees. Woodard et al (1963) reported that approximately 5.5% of all turkey eggs were laid in the dark period, and the frequency of these eggs tends to increase as the laying period progresses (Bixler and Ringer, 1968;Nestor and Bacon, 1982). This increase of eggs laid during the dark period is possibly a consequence of an increase in erratic oviposition associated with aging.…”