Drinking water contaminants (arsenic, cadmium, lead, benzene, and trichloroethylene). 1. Interaction of contaminants with nutritional status on general performance and immune function in broiler chickens.

The objective of this study was to examine possible interactions between drinking water contaminants and suboptimal nutritional status for performance and immune function in male broiler chickens. Experimental drinking water contained a mixture of arsenic, benzene, cadmium, lead, and trichloroethylene (TCE) at low concentrations (0.80, 1.3, 5.0, 6.7, and 0.65 ppm) and high concentrations (8.6, 13, 50, 67, and 6.5 ppm). These chemicals were selected because they are among the most common contaminants found in ground water near hazardous waste sites. The experimental diets included feed containing 50% added vitamins and minerals (V&M) and feed without added V&M. Increasing levels of drinking water contaminants and decreasing levels of V&M in diet resulted in significantly (P < or = 0.05) decreased water and feed intake, decreased weight gain, and suppression of natural, humoral, and cell-mediated immune response. In a paired-water study, feed consumption, body weight, and immune function were decreased in chickens provided low and high concentrations of the chemical mixture in drinking water compared with chickens given control drinking water equal to the volumes consumed by the chickens given the low and high concentration of mixture, respectively. A deficiency of dietary V&M caused increased sensitivity to adverse effects of drinking water contaminants.

Drinking water contaminants (arsenic, cadmium, lead, benzene, and trichloroethylene). 2. Effects on reproductive performance, egg quality, and embryo toxicity in broiler breeders.

Broiler breeder hens were used to determine the effect of drinking water containing a low concentration of a chemical mixture (arsenic, 0.8 ppm; benzene, 1.3 ppm; cadmium, 5.1 ppm; lead, 6.7 ppm; and trichloroethylene, 0.65 ppm) and a high (10 times greater than the low concentration of the chemical mixture) levels of the chemical mixture. These chemicals are present in ground water near hazardous waste sites. Water consumption significantly decreased in chickens provided the high concentration of the chemical mixture, whereas feed consumption was not affected in any treatment. There was a linear relationship between increasing concentration of the chemical mixture in drinking water and decreasing body weight of hens. The low concentration of the chemical mixture significantly decreased egg production and egg weight, and increased percentage embryonic mortality. These results suggest that reproductive function in hens is sensitive to adverse effects of contaminated drinking water.

Lighting programs for broilers that reduce leg problems without loss of performance or yield.

This study tested the effects of light schedules on performance and yields of broiler chickens. In Experiment 1, light treatments during Days 1 to 49 of age were: 1) 23 h light (L):1 h dark (D); 2) 16L:8D;3) 16L: 3D:1L:4D; and 4) 16L:2D:1L:2D:1L:2D. In Experiment 2, Light Treatments 1 and 2 were the same as Treatments 1 and 4, respectively, in Experiment 1; 3) 23L:1D Days 1 to 7, 16L:8D Days 8 to 14, the light period was increased by 2 h/wk during Days 15 to 35, and 23L:1D Days 36 to 42; and 4) 23L:1D Days 1 to 7, 16L:8D Days 8 to 14, 16L:3D: 2L:3D Days 15 to 21, 16L:2D:4L:2D Days 22 to 28, 16L: 1D:6L:1D Days 29 to 35, and 23L:1D thereafter. In Experiment 1, BW was greater in Treatment 4 than Treatment 2 at 22 (708 vs 642 g) and 49 d (2,948 vs 2,797 g), percentage leg problems was lower in Treatments 2 to 4 (9, 10 and 6%, respectively) than in Treatment 1 (20%), and percentage Grade A was greater in Treatment 4 than Treatment 2 (60 vs 46%) at 49 d. In Experiment 2, BW was greater in Treatment 1 (692 g) than Treatments 3 (617 g) and 4 (620 g) at 21 d, and the incidence of tibial dyschondroplasia was lower in Treatment 2 (3.1%) than Treatment 3 (15.3%) at 42 d. There were no differences for mortality among treatments in either experiment.

Lack of interactions between dietary lysine or strain cross and photoschedule for male broiler performance and carcass yield.

The purpose of this study was to test interactions of dietary lysine or strain crosses provided increased lysine with photoschedule on broiler performance and carcass quality. In Experiment 1, treatments were factorially arranged as two lysine levels [control grower and finisher (NRC, 1984) or control grower and finisher plus .15% L-lysine HCl] and two photoschedules [23 h light (L):1 h dark (D) or 14L:10D]. All birds received a control starter feed and dietary treatments were initiated at 22 d of age. In Experiment 2, treatments were factorially arranged as two strain crosses [Peterson x Arbor Acres (PAA) or Ross x Ross (RR)] and two photoschedules (23L or 16L). All birds received standard starter and standard grower and finisher plus .15% L-lysine HCl. There were no lysine by photoschedule or strain cross by photoschedule interactions in this study. The high-lysine diet increased BW, improved feed efficiency, increased lean carcass weight and yield of breast meat, and decreased abdominal fat and yield of thighs. The PAA strain cross had better feed conversion, fewer Grade A carcasses, more back bruises and breast blisters, greater yield of wings and drumsticks, and less yield of breast meat than RR. The 23L had greater BW, better feed efficiency, fewer breast blisters, greater carcass weight (Experiment 1), more abdominal fat (Experiment 2), lower yield of wings (Experiment 1), drumsticks, and thighs, and greater yield of breast meat than the treatments with shorter photoschedules. Increased dietary lysine did not compensate for decreased breast meat yield associated with 14L (Experiment 1).

Plasma concentrations of corticosterone and thyroid hormones in broilers provided various lighting schedules.

The purpose of this study was to measure plasma corticosterone and thyroid hormone concentrations in broilers exposed to various photoschedules. Day-old male broilers were placed on litter floors in light-controlled chambers. Four chambers were randomly assigned to each of four light treatments: 1) 23 h light (L):1 h dark (D) from 1 to 56 d of age (designated extended, E); 2) 1L:3D from 1 to 56 d (intermittent, I); 3) 6L:18D from 1 to 14 d and 1L:3D from 15 to 56 d (brief-I, BI); and 4) 6L:18D from 1 to 14 d and 23L:1D from 15 to 56 d (brief-E, BE). Blood samples were collected 0, 4, and 20 h after lights-on (1200 h) at 13, 41, and 55 d of age. Corticosterone concentration did not differ among light treatments or collection times and was decreased at 41 d compared with 13 d (.65 vs 2.11 ng/mL). Triiodothyronine (T3) increased and thyroxine (T4) decreased with age. At 13 d, there were light treatment by sampling time interactions for T3 and T4. Plasma T3 was elevated in Treatments BI (3.11 ng/mL) and BE (3.40 ng/mL) compared with Treatments E (2.39 ng/mL) and I (2.30 ng/mL) at 0 h; the former two treatments showed decreased T3 concentrations at 4 and 20 h compared with 0 h. Plasma T4 showed reciprocal changes to T3. There were no differences in T3 or T4 for light treatments or sampling times at 41 and 55 d.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of photoschedule and strain cross on broiler performance and carcass yield.

The purpose of the present experiment was to examine possible interactions of strain cross and age with photoschedule for broiler performance and carcass yield. Day-old male broiler chicks from strain crosses of either Peterson x Arbor Acres (PA) or Ross x Arbor Acres (RA) were placed in light-controlled chambers (5.6 lx) with either 23 h light (L):1 h dark (D) from 1 to 56 days (Treatment E) or 6L:18D from 1 to 14 days and 1L:3D repeated from 15 to 56 days of age (Treatment BI). There were age by light treatment and age by strain cross interactions for BW; Treatment E had greater BW than Treatment BI from 7 to 42 days, and the PA cross BW was greater than the RA cross BW from 1 to 42 days of age. Cumulative feed efficiency was improved by Treatment BI compared with Treatment E up to 49 days. There were no differences among main effects for mortality, and the incidence of leg problems increased with age. Fillet and tender yields (per lean carcass weight) were higher for Treatment E than BI and opposite responses were seen for drumstick and thigh yields. The RA cross showed higher fillet and tender yields than the PA cross and the opposite relationship was found for drumstick and wing yields.

Live performance and carcass yield of broiler strain crosses provided either sixteen or twenty-three hours of light per day.

The purpose of the present study was to compare a restricted (R) lighting program [16 h light (L):8 h dark (D)] with a standard extended (E) lighting schedule (23L:1D) for broilers. Experiment 1 was carried out during March and April (mean temperature of 23.3 C). Light treatments were 1) E; 2) R; 3) 16L:8D Days 1 to 21 and 23L:1D thereafter to 49 days (R3E); and 4) 16L:8D Days 1 to 14 and 23L:1D thereafter to 49 days (R2E). Treatments were factorially arranged with two strain crosses [Indian River x Arbor Acres (IA) and Peterson x Arbor Acres (PA)]. Experiment 2 was carried out during the summer (mean temperature of 27.0 C). Light Treatments E and R were factorially arranged with two strain crosses [Cobb x Arbor Acres (CA) and PA]. In Experiment 1, BW of Cross PA was greater than BW of Cross IA at 1, 14, 35, and 49 days of age. The percentage of birds with breast blisters was greater in Cross PA than IA. The incidence of broken clavicles was lower in Treatments R and R3E than in Treatments E or R2E. In Experiment 2, Treatment E had greater BW than R from 7 to 42 days of age, and BW of Cross CA was greater than that of PA from 1 to 48 days. Yield (percentage of lean carcass weight) of breast meat at 49 days of age was higher for Treatment E than R, and the percentage of birds with breast blisters was greater in Treatment R than E.(ABSTRACT TRUNCATED AT 250 WORDS)

Live performance and yields of broilers provided various lighting schedules.

The purpose of the present study was to measure performance and carcass yield from broilers maintained on photoschedules that may influence incidence of leg disorders. Day-old male broilers were placed on litter floors of light-controlled chambers. Four chambers were randomly assigned to each of four light treatments: 1) 23 h light (L): 1 h dark (D) from 1 to 56 days of age (designated extended, E); 2) 1L:3D from 1 to 56 days (intermittent, I); 3) 6L:18D from 1 to 14 days and 1L:3D from 15 to 56 days (brief-I, BI); and 4) 6L:18D from 1 to 14 days and 23L:1D from 15 to 56 days (brief-E, BE). Mean (+/- SEM) light intensity was 5.4 +/- .26 lx for all light treatments. At 13, 21, and 42 days of age, Treatments BI and BE had lower BW than Treatment E. The percentage of birds with leg abnormalities among treatments was greater at 56 days than at 42 days. The BI birds had significantly fewer leg abnormalities than E birds. There was an age by treatment interaction for the frequency of tibial dyschondroplasia (TD), with BI showing better recovery from TD at 56 days than other treatments. At 42 days of age, split breast yield (percentage of BW) was greater in E than I, and breast yield (percentage of lean carcass) was greater in E and BI compared with I. At 56 days of age, yield (percentage of BW) of tenders was lower in I and BI compared with E and BE.(ABSTRACT TRUNCATED AT 250 WORDS)

Performance of two male broiler breeder strains raised and maintained on various constant photoschedules.

The purpose of the present study was to examine the interaction of constant photoschedules and genetic background on performance of male broiler breeders. Day-old cockerels from two BW strains were placed on litter floors in light-controlled chambers. Light treatments (LT) (60 lx) consisted of 2, 4, 8, 16, and 24 h light/day. At 9 wk of age, birds were individually caged and evaluated biweekly for semen production. Venous blood samples were collected at 16, 32, 48, and 64 wk of age. Data for testes weight, histology, and morphometry were obtained at 64 wk. Age at first semen production showed a cubic response in the levels of LT with earliest semen production from 4 and 8 h light (187.0 and 188.2 days, respectively). The BW was linear in the levels of LT within week; average BW was generally greater for birds on short LT than for birds on longer LT. Semen concentration was also linear in the levels of LT within week; increased semen concentration occurred with short LT. Changes in semen weight and spermatozoa count per ejaculate across the levels of LT differed for strain. A larger percentage of males produced semen in the less than or equal to 8 h LT than in the 16 or 24 h LT. Plasma testosterone was lower at 16 wk compared with later ages, and a positive linear relationship existed between testosterone level and hours of light. There was a cubic LT effect for testes weight per BW with larger values for less than or equal to 8 h LT compared with 16 or 24 h LT.

Examination of the physical characteristics in a diverse group of dwarf White Leghorn pullets before and after first oviposition.

The purpose of the present experiment was to measure changes in physical variables with sexual maturity (SM), the oviposition of first egg, in sex-linked dwarf pullets when SM was delayed by the photoschedule. Offspring were produced from matings of dwarf Single Comb White Leghorn chickens divergently selected for high (H) or low (L) 20-wk BW. At 15 wk of age, pullets from half-sibling sets were randomly assigned to a diet either of low energy (LE: 2,500 kcal/kg of ME, 15% CP) or high energy (HE: 3,000 kcal/kg of ME, 15% CP) and were placed in cages. When a pullet reached SM, the mature (M) pullet and an immature (I, absence of oviposition), half-sibling pullet on the same diet were sampled for BW as well as for the weights of abdominal fat, liver, ovary, oviduct, whole egg (M pullets), yolk, and shell and for the number of rapidly developing follicles. Proximate measurements (wet weight) were made for defeathered carcasses and livers as well as for ovaries and oviducts. There were significant (P less than or equal to .01) line effects for BW at SM (H greater than L); age at SM (L greater than H); weights for the liver, abdominal fat, egg, albumen, shell (H greater than L), and yolk (L greater than H); number of developing follicles (H greater than L); percentage of carcass protein (L greater than H) and of fat (H greater than L); as well as for liver protein (L greater than H), fat (H greater than L), and ash (L greater than H). There were significant (P less than .01) diet effects for abdominal fat (HE greater than LE) and shell weight (LE greater than HE). There was a line-by-diet interaction for total feed intake and for total energy intake from 15 wk to oviposition of the first egg. There were significant (P less than .01) SM effects (M greater than I) for BW at SM, number of developing follicles, oviduct weight, and fat content of the reproductive organs; also, reproductive organ weights accounted for differences in BW at SM. There was an interaction for line by maturity state; the L pullets showed a greater increase in ovarian weight with oviposition of the first egg than did the H pullets. The results of this study indicated that the threshold requirements for BW, composition, or both, for SM may have been exceeded in Leghorn-type chickens when photoscheduling was used to delay the onset of SM.

Effects of dietary energy on semen production, fertility, plasma testosterone, and carcass composition of broiler-breeder males in cages.

One hundred-fifty broiler breeder males were raised to 17 wk of age in floor pens using standard procedures. The males were placed in individual cages at 18 wk of age in an environmentally controlled house and fed for recommended BW to 29 wk of age. At 30 wk of age, birds were randomly assigned to one of five dietary treatments. Diets consisted of 10% CP and 1,600, 2,000, 2,400, 2,800, or 3,200 kcal ME/kg feed (Groups 1600, 2000, 2400, 2800, and 3200, respectively). Birds were ejaculated twice weekly; semen characteristics, BW, and serum testosterone (T) were determined every 4 wk. Fertility determinations were made at 38 and 48 wk. At the end of the experiment (60 wk of age), body composition was measured. The percentage of body fat was reduced in Groups 1600, 2000, and 2400. Body weight, percentage of males producing semen, semen weight (SW), total spermatozoa per ejaculate (TS), and T were all reduced in Groups 1600 and 2000; semen concentration (SC) was reduced in Group 1600, compared to the other treatments. Group 2400 had the highest percentage of carcass protein; Groups 1600 and 3200, the lowest percentage. Body weight, percentage of protein, and percentage of fat were quadratically related to dietary energy. The T, SW, SC, and TS were linearly and positively related to the energy level.

Effects of ad libitum and restricted feeding on semen quantity and quality, body composition, and blood chemistry of caged broiler breeder males.

One hundred eighty, 16-wk-old, caged broiler breeder males were randomly assigned to one of three feeding treatments: 1) restricted feeding (RES), breeder-recommended levels minus 25%; 2) control feeding (CON), breeder-recommended levels; 3) full-fed (FF), ad libitum feeding. Each group received the same corn-soybean diet, with 15.5% CP and 2,878 kcal ME/kg feed. The males were ejaculated twice weekly, and BW, semen characteristics, hematocrits (HCT), and serum testosterone (T) were determined every 4 wk. At 17, 35, and 56 wk of age males were killed for body composition determination of percentages of protein, moisture, and fat. The FF males were heavier throughout the experiment than either CON or RES males. The FF group had a higher percentage of males in semen production than CON, which had a higher percentage of males in production than RES. Males of the FF group produced more semen with a higher spermatozoa concentration (SC) than CON, which males had higher spermatozoan concentrations than RES. The FF males had a higher level of T overall than CON or RES males. Hematocrits of FF were higher than those of CON birds, which were higher than those of RES birds. Body compositions were not significantly different among treatments at 17 wk; however, at 35 and 56 wk, FF males had a higher percentage of fat and a lower percentage of protein than birds in the other two groups. Significant positive correlations were found between body fat and the variables HCT, BW, semen weight (SW), and SC. Body weight was positively correlated with SW, and T was correlated with HCT.

Evaluation of bioelectrical impedance for estimation of body composition in 8-week-old broilers.

Bioelectrical measurements (resistance and reactance) were obtained from 35 male and 45 female 8-wk-old broilers using a tetrapolar technique. Body weight, dorsal body length (BL), thigh diameter (TD), and proximate analysis (percentage fat, protein, and moisture) were also ascertained. Twenty birds of each sex were randomly assigned to a calibration group and the remaining birds to a prediction group. Data for birds in the calibration group were used to generate regression equations for estimating whole body composition. Data from birds in the prediction group were collected for possible validation of the calibration equations. Repeatability values for resistance (Re), reactance (Xc), and composition variables were equal to or greater than .78. Coefficients of determination (R2) among percentage body moisture, fat, and protein and body and bioelectrical measurements in males were .41, .36, and .24 (P less than .05), respectively. Percentage moisture in females was predicted by TD2/BL (R2 = .22, P less than .05). Body composition was not adequately predicted by variables measured in this study.

Effects of feeding regimen during early development on body composition, gastrointestinal tract size, and semen quality of broiler breeder cockerels after maturation.

Broiler breeder males were randomly assigned at 3 wk of age to one of three feeding treatments: 1) limited amount daily feeding (LD), 2) skip-a-day feeding (SAD), or 3) limited time feeding (LT). The same diet (16% CP and 3,011 kcal ME/kg) was provided from 3 to 22 wk of age to each treatment. The amount of feed or feeding time was adjusted to maintain recommended BW across treatments. At 22 and 34 wk of age, testes and gastrointestinal (GI) weights and carcass compositions were obtained. From 22 to 34 wk, birds were individually caged and fed ad libitum a breeder diet (15.5% CP and 2,878 kcal ME/kg). Males were ejaculated twice weekly, and BW and semen characteristics were recorded weekly. No significant differences existed among treatments for BW or body composition at 22 wk, but SAD birds had heavier crops and lighter gizzard weights than either LD or LT birds. Sexual maturity occurred 10 days earlier in the LD group than the SAD group; however, the LD group had reduced semen yields and spermatozoa concentrations compared to those in the SAD group. At 34 wk, there were no significant differences among body or GI weights, body moisture, or ash among the treatment groups. Birds in the LD group had heavier livers, greater amounts of body fat, smaller testes, and reduced body protein than those in the other treatments.

Factors affecting broiler breeder performance. 7. Effect of varying levels of dietary protein on the development and reproductive performance of the dwarf broiler breeder.

Vedette dwarf broiler breeder female chicks were raised in floor pens and fed a standard starter ration. At 3 wk of age, 1,032 pullets were divided into four dietary treatment groups (258 bird/treatment). Birds were transferred into individual cages at 18 wk of age and at 21 wk of age assigned to one of four laying rations. Dietary treatments consisted of a 4 X 4 factorial design with four developer diets (12, 14, 16, and 18% protein) and four layer diets (12, 14, 16, and 18% protein). Body weight was determined at 6, 12, and 17 wk of age and thereafter at 4 wk intervals. Hen-day egg production was determined weekly from 21 to 58 wk of age. Specific gravity and egg weights were measured at 4-wk intervals on eggs collected over 4-day periods. Fertility and hatchability were measured at 32, 34, and 44 wk of age on the one-half of the birds in each treatment that had been artificially inseminated weekly with .05 mL of semen from Ross males. Embryonic mortality and chick weights of offspring were recorded when the breeder flock was 32 and 44 wk of age. Dietary treatment had a significant effect on body weight (P greater than .05) at Week 12, (12% and 14% vs. 16% and 18%) but by Week 17 differences were no longer significant. Significant differences in body and egg weights during the laying cycle were detected (P less than .05), with hens receiving the higher protein (16% and 18%) laying diets exhibiting heavier body and egg weights.(ABSTRACT TRUNCATED AT 250 WORDS)

Fluorometry of poultry semen: influence of dilution and storage on chicken spermatozoal viability and fertility.

Two experiments were conducted to measure the effects of semen dilution and storage time (0, 1, 2, 3, 4, 24, and 48 h) at 22 C on spermatozoal viability (i.e., membrane permeability to ethidium bromide) and to determine the relationship between concentration of viable spermatozoa inseminated (25, 50, 100, and 200 x 10(6] and fertility. In Experiment 1, percentages of dead spermatozoa remained relatively constant during the 4-h postcollection period but increased significantly (P less than .05) at 24 and 48 h. Sperm viability after 48 h was significantly higher in diluted semen than in undiluted semen. Percent (PF) and duration of fertility (DF) from undiluted semen significantly declined during the 4-h postcollection period compared with fertility of diluted semen. In Experiment 2, both PF and DF improved as the concentration of viable spermatozoa increased. Fertility was not significantly improved by inseminating more than 100 X 10(6) viable spermatozoa. The fertilizing capacity of chicken spermatozoa from undilated semen was affected during storage before membrane permeability to ethidium bromide was altered.

Semen and carcass evaluation of broiler breeder males fed low protein diets.

At 43 days of age, 246 broiler breeder males were randomly assigned to either a 9, 12, or 15% protein diet (isocaloric) fed on a restricted basis until birds were 50 wk of age. Birds fed the 15% protein diet served as the control group for maintaining body weight. All groups received equal quantities of feed. Semen production was monitored weekly from 17 through 49 wk of age. Semen was evaluated for volume, concentration, and number of spermatozoa per ejaculate during four periods: 25 through 30, 36 through 37, 42 through 43, and 48 through 49 wk of age. Carcass composition and testes weight were sampled at 22 and 28 wk; at 50 wk of age all remaining males were analyzed. The dietary protein effect on body weight was linear (P less than .05). Birds fed the 9% protein diet had the lowest weights, while birds fed 12 and 15% protein became similar in body weight with increasing age. Semen volume, concentration, number of spermatozoa per ejaculate, and testes weight were unaffected by dietary protein level. The percentage of males that produced semen when fed the 9% protein diet was greater (P less than or equal to .09) with males fed 12 and 15% dietary protein. Dietary protein had a significant negative linear effect (P less than or equal to .001) on percent carcass fat at 50 wk of age but no effect on percentage carcass protein. Reducing dietary protein to 9% decreased male body weight slightly, increased carcass fat, and had no adverse effects on semen production through 50 wk of age.

Egg production efficiency in dwarf lines selected for high and low body weight as influenced by feed restriction.

Hens from dwarf Single Comb White Leghorn lines selected for four generations for high (H) and low (L) body weight (BW) plus randombred controls (C), sixty birds per line, were placed in cages at 18 wk of age and randomly assigned to either a full-fed (FF) or restricted-fed (R) (10 percent less than FF group) treatment. Birds received a layer ration having 16% protein and 2,816 kcal/kg metabolizable energy. Water was provided ad libitum. Individual BW and egg weights (EW) were obtained, and daily feed intake (DFI), egg production (EP), performance efficiency (PE) [egg mass (EM) per BW], and feed efficiency (FE) [EM/DFI] were calculated for 28-day periods from 18 to 41 wk of age. There were significant line, treatment, and age effects and line by age interactions for BW, EW, EM, DFI, and PE; FE was significantly influenced by age. There were significant treatment by age interactions for BW, DFI, and FE. Feed intake, BW, and EW were greatest for FFH hens and increased in all lines with age. Maximum EM occurred during 30 to 33 wk for RH and RL hens, during 34 to 37 wk for FFH, and during 38 to 41 wk for FFL. Maximum PE occurred during peak EP. Maximum FE for FFH and FFL occurred during 26 to 29 wk and during 30 to 33 wk for RH and RL. Data for C hens were intermediate to the other lines. Feed efficiency was improved by restriction for L hens from 26 to 33 wk and for H hens from 26 to 33 wk and for H hens from 26 to 41 wk of age.

Body composition and other physical parameters as determinants of age at sexual maturity and performance efficiency in dwarf hens divergently selected for body weight.

Hens in this study were produced from random breeding within lines (high, low, and control) of dwarf White Leghorns that had been divergently selected for four generations for 20-week body weight. Birds were weighed at 10 weeks of age and placed in individual cages at 18 weeks of age. Body weights, shank lengths, and egg weights were obtained at sexual maturity (day of first egg) and at 4, 8, 12, and 16 weeks after sexual maturity. Egg production was recorded during 28-day periods. Thirty hens/line were sampled at sexual maturity and at the above times after sexual maturity for body composition (percent fat, protein, moisture, and ash). High line hens showed increased percent body fat and reduced percent protein and moisture compared to low and control hens. Coefficients of determination (R2) for age at sexual maturity and body weight were small (R2 less than or equal to .20) for high and control hens. There were no meaningful relationships between body weight or other physical measurements and sexual maturity in low hens. There were no significant relationships between body composition and age at sexual maturity in high and control hens. There was a strong cubic association (R2 = .73; P less than .001) between percent ash and age at sexual maturity in low hens, although the biological importance of this relationship was uncertain. Coefficients of determination between body weight and performance efficiency (egg mass per body weight) were small to moderate (R2 = .04 to .46) for high and control hens.(ABSTRACT TRUNCATED AT 250 WORDS)

Sperm release from the uterovaginal storage gland of the chicken: A perfusion study.

In vitro and in vivo intraluminal perfusions of the uterovaginal junction of the oviduct were performed in an attempt to quantitate sperm release from the uterovaginal sperm host glands (UV-SHG) of breeder hens. Spermatozoa were present in the perfusate at all time periods examined. However, the quantity of spermatozoa recovered showed a significant (P<0.0001) decline over a 2-h perfusion period in all experiments. Furthermore, histological examination of the perfused oviduct revealed significantly lower percentages (P<0.05) of UV-SHG containing spermatozoa compared to unperfused control oviducts. The perfusion techniques used in this study seemed to influence the pattern of sperm release from the storage glands.