The Influence of Force Molting on the Incidence of Uncollectable Eggs

Self Cite

Performance of force-molted hens as influenced by premolt production was determined in two experiments using 720 Babcock hens. Hens selected to be laying at a low (41%), average (59%), and high (75%) rate of production were divided into two groups. One half of the hens were force molted (FM) and the other half served as controls (CON). On completion of the fasting period, blood was collected for chemical analyses from 10 hens per group. These hens were then necropsied and weights of the ovary, oviduct, liver, and fat pad determined. During the last 4 weeks of the postmolt period, dietary calcium was increased from 3.5 to 4.5% in half of each group.Postmolt production was directly related to premolt production. The hens laying the highest rate premolt showed no improvement, whereas those laying at the lowest rate showed the greatest improvement. The"FM hens exhibited a lower incidence of shell-less eggs than CON hens. Premolt production appeared to have little influence on postmolt egg weight, organ weights, and blood constituents. However, shell weight and egg specific gravity were significantly improved by force rnolting^ Increasing dietary calcium had no significant influence on shell weight and specific gravity in FM hens in either experiment but significantly increased specific gravity and shell weight of CQN hens during Experiment 2.It >Kas^concluded that most of the improvement in production in force-molted hens was caused by a reduction in shell-less eggs and"not by an increase in ovulation. Also, only a portion of the improvement in shell quality could be explained by an increase in feed intake (calcium intake) after molting due to the increase in production. An improvement in calcium metabolism was postulated to be a major cause of improved shell quality. (

Section: Resultssupporting

confidence: 93%

Influence of Premolt Production on Postmolt Performance with Explanation for Improvement in Egg Production Due to Force Molting

Roland

Brake

1982

Self Cite

“…In contrast, those hens of the HS egg layer group had a total average hen-day production of 60.0% with only 3.2% of the total representing SS and SL eggs. The production of SS eggs was reduced following an induced molt, which agrees with observations of Roland and Bushong (1978).…”

Section: Egg Productionsupporting

confidence: 89%

“…3 Present address: Governors State University, Division of Science, University Park, IL 60466. SS and SL egg production for at least 13 weeks postmolt (Roland and Bushong, 1978). Improved postmolt performance is due primarily to a reduction in SL egg production rather than an increase in ovulation (Roland and Brake, 1982).…”

Section: Introductionmentioning

confidence: 98%

Effects of an Induced Molt and Shell Quality on the Physical Dimensions and Mineral Composition of Eggs and Intrauterine pH ,

Klingensmith

Hester

1985

The relationship between force-molting and egg shell quality on the physical dimensions, water vapor conductance, air pore characteristics, and shell mineral content of eggs was investigated in Experiment 1. Hard-shelled (HS) and soft-shelled (SS) eggs were collected at 0700 or 1100 hr from force-molted and nommolted hens between 95 and 99 weeks of age. For Experiment 2, intrauterine pH was measured in vivo, immediately following the oviposition of a HS, SS, or shell-less (SL) egg by 107-week-old force-molted and nonmolted hens.Egg weight, percent shell, shell surface area, water vapor conductance, pore density, and the number of pores/egg were similar among HS eggs produced by molted and nonmolted hens, while shell weight, shell thickness, shell volume, shell calcium, pore radius, and total pore area were significantly greater in eggs produced by molted than nonmolted birds. Shell thickness, percent shell, and shell phosphorus content were greater in HS eggs collected at 0700 hr than 1100 hr. Shells from HS eggs were thicker content were greater in HS eggs collected at 0700 hr than 1100 hr. Shells from HS eggs were thicker and had higher ash, calcium, magnesium, and phosphorus contents when compared to shells from SS eggs. Shell manganese levels were lower in HS eggs produced postmolt, while molting did not affect the shell manganese content of SS eggs. The number of pores/cm^ were lower in HS than SS eggs. No significant differences due to molt type or egg type were observed for intrauterine pH measured in vivo following the oviposition of HS,

“…Noles (1966) and Nakazawa et al (1970) also reported that egg weight was unaffected by molt. Roland and Bushong (1978) stated that force molting generally had little influence on egg weight. Improved shell quality, as well as albumen quality, during the 20-week postmolt period was reported by Hembree et al (1980).…”

Section: Resultsmentioning

confidence: 98%

Effects of Forced Molt Period on Postmolt Performance of Leghorn Hens

Lee

1982

Sixty-four-week-old Single Comb White Leghorn (SCWL) hens were subjected to the following treatments: 1) no forced molt (control); 2) forced molt for 4 weeks (FM 4 ); 3) forced molt for 6 weeks (FM 6 ): and 4) forced molt for 8 weeks (FM 8 ). Molt was induced by restricting feed, water, and photoperiod. Data were analyzed at the 5% level of probability.During the early postmolt period (72 to 76 weeks of age), birds in all FM groups consumed significantly more feed and had significantly higher hen-day egg production than birds in the control group. Albumen height and shell thickness measured at 76 weeks of age were significantly improved by all FM treatments.During the postmolt period (72 to 124 weeks of age), hens in the FM 8 group had the highest hen-day egg production and best feed efficiency, whereas birds in the control group had the lowest hen-day egg production and poorest feed efficiency. However, these differences were not statistically significant. Percent hen-day egg production was positively and significantly correlated with FM period. Mortality rate during this period was significantly lower for the FM 4 and for the FM 8 groups as compared to the control group. Egg shell thickness was significantly improved in two out of the three FM treatments. (