White Plymouth Rock Pullets Research Articles

Growth to sexual maturity of dwarf and nondwarf White Rock chickens divergently selected for juvenile body weight

Growth from hatching to the onset of lay (sexual maturity) was studied in White Plymouth Rock pullets from lines selected for high (HN) and low (LN) 56-day body weight, their reciprocal F1 crosses, an F2 cross, and two dwarf populations originating from the HN and LN parental lines. The highest R(2)s for describing growth for all populations except HN were obtained when body weight was expressed relative to body weight at sexual maturity. Modes of inheritance differed depending on whether patterns of growth were expressed in a chronological time frame or on a physiological basis. Heterosis observed for age at sexual maturity and for body weight after the age when selection was made was not in evidence when ages and weights were expressed as a proportion of those at sexual maturity.

Ovum formation and multiple ovulation in lines of white Plymouth Rocks and their crosses.

The production of double-yolked eggs and the duration of the rapid growth phase of yolks were measured in parental lines of White Plymouth Rock pullets and their crosses over 30 d, commencing with the day of first egg. Significant differences were found between mating combinations in the incidence of multiple-yolked eggs, but not in the period of rapid yolk growth. Heterosis and recombination effects for multiple ovulation were respectively -9% and -66% of the mean, while the corresponding values for the period required for rapid yolk growth were -1% and -5%. Three double-yolked eggs were observed containing yolks which differed by 3 d in their periods of rapid growth. Hypotheses are were presented for the origin of double-yolked eggs.

Effects of Environmental Temperature on the Concentration of Serum Estradiol, Progesterone, and Calcium in Maturing Female Domestic Fowl

The effects of environmental temperature on serum estradiol, progesterone, and calcium concentration in White Plymouth Rock pullets were investigated from 12 to 24 weeks of age.Pullets were grown from 10 weeks of age in individual cages at constant environmental temperatures of 13 C, 25 C, or 35 C. Serum estradiol and progesterone concentrations were measured by the use of radioimmunoassay. Serum calcium was measured by an atomic absorption spectrophotometer.There were no significant differences in growth rate or concetration of serum estradiol, progesterone, or calcium between pullets kept at 13 C and 25 C. There was a marked increase in serum estradiol and calcium concentration before onset of lay. There were high correlations between serum estradiol and calcium concentration in pullets kept at 13 C (r = .803) and 25 C (r = .813). Progesterone concentration in pullets kept at 13 C and 25 C reached a peak at 20 weeks of age. By contrast, pullets kept at 35 C had significantly lower growth rates and lower concentrations of serum estradiol, progesterone and calcium than those kept at the other two environmental temperatures. The high environmental temperature of 35 C inhibited growth and delayed sexual maturation of pullets.

Comparisons of frequencies and egg shell characteristics of broken and intact eggs within diverse populations of chickens

1. Differences were found among eight populations of White Plymouth Rock pullets in the frequency of broken eggs. 2. The shells of such eggs were thinner than those of intact eggs in seven of the populations. 3. The number of defective eggs, the specific gravity of the eggs, and the percentage hen‐day egg production of normal eggs were significantly correlated within populations with the incidence of broken eggs. 4. No significant correlations were found within populations between the incidence of egg breakage and either egg weight, body weight, or shank length.

Frustration and production in purelines of chickens and their reciprocal crosses

Frustration, fear and production traits were measured in four populations of White Plymouth Rock pullets that were maintained singly in wire cages. The populations consisted of two purelines and their reciprocal crosses. Significant differences were found between the purelines for frustration, as measured by head flicking. Means for the cross-line pullets were similar to that of the parental line with lower value, and significantly different from the parental line with the higher value. Highly significant differences were found among lines for fear, with the average of the reciprocal cross means being the same as the mid-parent average of the purelines. Within population, phenotypic correlations showed no relationship between frustration and fear. Also there was no evidence, under our husbandry conditions, that frustration and fear were associated with either body weight, age at first egg or egg production.

Utilisation of palm, groundnut and melon seed oils by pullets

Synopsis Three oils available locally, palm, groundnut and melon seed, were analysed; melon seed oil was found to contain the highest proportion of unsaturated fatty acids and palm oil was the most saturated. The addition of these oils either at 6 per cent or 10 per cent levels to rations improved egg production by White Plymouth Rock (WPR) pullets but not by Rhode Island Red (RIR) pullets. However, 6 per cent melon seed oil improved the size of eggs laid by RIR. Using 10 per cent melon seed oil in the experimental ration improved egg shell thickness in both breeds. For both breeds 6 per cent groundnut oil depressed calcium absorption, while 6 per cent melon seed oil reduced calcium absorption in only WPR pullets. Addition of 6 per cent and 10 per cent palm oil or 10 per cent of either groundnut oil or melon seed oil enhanced calcium absorption by both breeds. The cholesterol content of egg yolk lipid increased as the degree of unsaturation of the dietary oil increased.

Studies on the Restriction of Feed Supply for Growing Mealt-type Pullet

Collaborative experiments at 6 Prefectural Poultry Experiment Station with 1, 444 White Plymouth Rock pullets were carried out to study the effect of regulation of body weight by restricting the daily supply of feed. Feed supply was so restricted that body weight of pullets at 24 weeks of age was either 80, 70 or 60% of that of control pullets fed ad libitum in each Experiment Station. After 24 weeks of age, all the pullets were fed the layer diet full.1. Pullets kept their body weight at 80% level started to lay almost simultaneously and with similar egg weight to the control pullets. In average, they produced hatching egg at the rate of 5.6% higher with 1.5yen/egg less feed cost than those of the control did.2. Pullets kept their body weight at 70% level delayed in sexual maturity by 5 days and layed a significantly heavier first egg. The production of hatching egg was 9.7% higher and feed cost per hatching egg was 2.0 yen lower then those of the control, the difference being significant at 1 and 5% levels, respectively.3. Pullets kept their body weight at 60% level delayed in sexual maturity by 16 days and layed a significantly heavier first egg. The production of hatching egg was 7.3% higher and feed cost per hatching egg was 3.8 yen lower than those of the control, the difference being significant at 5 and 1% levels, respectively.4. Summarizing all of the data, it was suggested that body weight at 24 weeks of age should be kept at the level less than 70% of the control to get better performance in laying period.Little effect on mortality of the pullet was observed among the different feeding programs.

Effect of Iodinated Casein and Thiouracil on Free Amino Acids in the Blood Plasma of Chicks

IN A previous paper (Shao and Hill, 1968) it was reported that thiouracil as a dietary supplement reduced the concentration of free lysine, threonine, tryptophan, methionine and leucine in the blood plasma of chicks. The present paper gives the results of experiments in which thiouracil and/or iodinated casein were added to a basal diet and extends the observations to several additional amino acids.EXPERIMENTALThe basal diet, essentially a wheat, corn soybean meal mixture, was described in detail by Shao and Hill (1968). White Plymouth Rock pullets were fed this diet from day old to 7 days of age and then divided on the basis of weight into lots of 12 chicks each. The experimental diets were assigned to these lots at random, each diet to 4 lots and the experiments continued for another 14 to 15 days. Blood samples were removed from each chick in two lots per treatment…

Studies on the Grower Diet for Meat-type Pullet

Two handred and fifty White Cornish pullets and 225 White Plymouth Rock pullets hatched in April or May, 1955, were reared from 10 to 49 weeks of age in 3 poultry experiment stations on either medium-energy control diet or low-energy, high fibre diet, on either full-feeding or restricted program. The collaborative experiments were planned based on factorial design with 3 factors, i.e. differences in feeding program, in breed and in environmental and other condition among the experiment stations.In 2 of the 3 experiment stations, the pullets of each breeds were grouped into 5 lots at 10 weeks of age, while in the third station at 24 weeks of age. Control grower diet containing 16% of crude protein and 66% of total digestible nutrients (TDN) (approximately corresponding to 888 kcal of productive energy (PE) per pound) were full fed to Lot 1 and to Lot 4 on restricted basis. High fibre grower diet containing 14% of crude protein and 56% of TDN (corresponding to 730 kcal of PE/lb.) was full fed to Lot 2 and to Lot 5 on restricted basis. To Lot 3, anotherhigh fibre diet containing 16% of protein and 56% of TDN was fed ad libitum. The pullets on restricted program were full fed for 6 days and kept without feed on the last day ofthe week. At 24 weeks of age, the pullets fed the control grower diet were switched to the control layer diet containing 18% of crude protein and fortified with calcium. The pullets fed the high fibre grower of 14% of crude protein were switched to the high fibre layer diet containing the same level of protein to and higher level of calcium than the grower diet. The pullets in Lot 3 were fed the high fibre layer diet containing 18% of protein and fortified with calcium. All the layer diets contained the same level of energy to that in the corresponding grower diet.Feed intake of the pullets on the high fibre grower was 16% more but their growth rate was 8% lower than those on the control diet. Sexual maturity measured as 50% production was delayed for 22 days by feeding the high fibre grower. However, performance in laying period, i.e. egg production, number of hatchable eggs per lot and mortality, was little influenced by high fibre grower feeding, although feed intake of the pullets was 9% more and 44 weeks body weight 6% less than those on the control diet. Hatchability of eggs on the high fibre diet was slightly (4%) higher than that of those on the control diet, although the difference was not significant statistically.Restricted feeding of the control diet, skipping a day in a week, showed little effect on growth rate, feed intake in both growing and laying stages, egg production, number of hatchale eggs and hatchability, although it delayed sexual maturity for 10 days. 44 weeks body weight was 4% and mortality was 19% less than those on the full feeding program.It was found that either of the programs, high fibre diet feeding or skip-a-day in a week, giving slight influence on the performance of the breeding hen, was not too efficient for the enhancement of productivity. However, the combination of the 2 programs, skipping a day in a week on high fibre diet, showed deleterious effect on the performance, lowering significantly the egg production. The pullets on the restricted feeding program seemed to counteract the ill effect of restriction by increasing the over-all feed intake, but with the combination of mechanical restriction of the high fibre diet, the pullets could not counteract completely.

Failure of a Choline Deficient Diet to Produce Muscular Dystrophy in the Chick

Hove and Copeland (1954) observed that rabbits fed a diet deficient in choline, but adequate in vitamin E, developed dystrophic lesions. However, there are no studies reported on the possible involvement of choline in the dystrophy syndrome of other species.Because of the inability of chicks to synthesize choline readily (Jukes, 1941) it is relatively easy to produce a severe choline deficiency in this species. This has been done in the following experiment, and the muscle tissue examined for evidence of dystrophic lesions.Sixty day-old White Plymouth Rock pullets were divided into 4 groups of 15 birds each. Two groups were fed a diet based on 20% of casein and 1% of l-arginine HCl (Jenkins et al., 1962) but supplemented with 100 I.U. of vitamin E per kg., 0.3% of dl-methionine, 0.6% glycine and 0.5 p.p.m. of selenium, and two groups were fed the same diet but with choline omitted… .

Cystic Remnants of the Right Müllerian Duct and Egg Production in Two Strains of White Leghorns

TWO strains of Single Comb White Leghorns developed at Cornell University have been shown to differ in mortality caused by large cystic right oviducts (Williamson, 1963). Mortality from this disorder was 2.5 percent in Strain A versus 0.8 percent in Strain B. Both strains have been maintained as closed flocks for more than 24 years.Cystic remnants of the right Müllerian duct have been reported by numerous investigators (Willier, 1927; Domm, 1940; Blount, 1947; Webster, 1948; van Tienhoven, 1957; Winter, 1958; Sell, 1959). Various cases of complete or partial development of the right oviduct have been reported by other workers (see McBride, 1962).Morgan and Kohlmeyer (1957) reported well-developed right oviducts in an inbred line of Rhode Island Reds. Morgan and Greb (1959) suggested that the cause may be due to hormonal imbalance or specific tissue-regression suppressors. Sell (1959) reported a similar situation in White Plymouth Rock pullets. Van Tienhoven…

The Efficacy of Sulphur Amino Acids and Related Compounds for Protection Against the Development of Muscular Dystrophy in the Chick

Chicks fed purified rations low in tocopherol and the sulphur amino acids develop muscular dystrophy in the breast musculature which can be prevented by supplementing the basal diet with methionine, cysteine, cystine, or alpha tocopherol acetate (Machlin and Shalkop, 1956; Jenkins et al., 1962). The mechanism(s) by which the sulphur amino acids and vitamin E prevent muscular degeneration are not known. Our knowledge that methionine is irreversibly converted to cysteine and cystine in the tissues of the bird suggests that the biopotency of methionine may be correlated to its ability to form these amino acids. The experiment reported here was a preliminary investigation of the relation of sulphur amino acid structure to the protection provided against the development of muscular dystrophy in the chick.Day-old, White Plymouth Rock pullets were fed a tocopherol and cystine-deficient basal ration containing 20% casein and 1% l-arginine HC1 (Jenkins et al., 1962) for one …

The Effect of Penicillin and Streptomycin in Diets for Breeding Hens

Although reports by several workers have indicated antibiotics to be of little value in diets for mature chickens, Waibel et al. (1952) have reported supplementation of penicillin to the breeder diet to cause an increased deposition of biotin and folic acid in the egg yolk without producing a measureable effect on egg production, body weight, or hatchability. It was thus suggested that a diet suboptimal in biotin, folic acid, or any other nutrient essential for good hatchability might be improved by the addition of an antibiotic. Herewith reported are a series of experiments with breeder hens which have been conducted under practical conditions and have demonstrated a beneficial effect with the use of penicillin or streptomycin supplements.New Hampshire or White Plymouth Rock pullets from the experiment station flock which had not received antibiotics during the growing period were equally distributed by physical selection into the respective groups as shown .

Thyroprotein and Fat in Laying Diets

CONFLICTING conclusions concerning the effect of thyroprotein (iodinated casein) upon the reproductive performance of chickens have been reported by different investigators. Rhode Island Red and White Leghorn females of all ages responded to thyroprotein administration by greater egg production according to Turner, Kempster, Hall and Reineke (1945): Turner, Kempster and Hall (1946); Turner and Kempster (1948); and Turner (1948). Negative results were reported by Hoffmann and Wheeler (1948), Hutt and Gowe (1948) and Godfrey (1949).Turner (1948) observed no effect of estrogens and androgens upon egg production of White Plymouth Rock pullets. Administration of thyroprotein and dianisylhexene in combination was equally effective as administration of thyroprotein alone.Berg and Bearse (1951) reported a highly significant decrease in egg production and lowered body weights of White Leghorn pullets fed 15 grams of thyroprotein per 100 pounds of feed.According to Savage, Turner, Kempster and Hogan (1952), thyroprotein had no effect on .

Relation of Body Weight and Egg Weight in the Domestic Fowl

POULTRY breeders try to establish large egg size in their stock because present marketing agencies consider large eggs desirable. Information which contributes to a more thorough understanding of egg weight in the domestic fowl should be helpful to those breeders who are attempting to establish this character in their stock. This paper reports the results obtained at the Missouri Agricultural Experiment Station from a study of the relationship of body weight and egg weight in chickens.DATAThe data used for this investigation were obtained from records on White Plymouth Rock pullets which were hatched in ten consecutive weekly hatches beginning the first week in February, 1932. Each hatch received the same general care and management while being brooded and reared.The pullets kept were considered suitable for laying purposes. They were divided into eight pens and fed experimental rations but there was no significant differences in the size of .