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Biomedical subjects

C D McDaniel

Publications and source records attributed to C D McDaniel.

30 records · Page 2Linked to original sources
PubMed1996

Age effect of male and female broiler breeders on sperm penetration of the perivitelline layer overlying the germinal disc.

An experiment was conducted to test the effect of age (male and female) on the number of spermatozoa penetrating the perivitelline layer (PL) overlying the germinal disc (GD) in broiler breeders. Eighty young broiler breeder hens (39 wk old, Y), and 80 old spent broiler breeder hens (69 wk old, O) were randomly divided into eight groups of 20 hens each by age. Hens were inseminated weekly for 4 consecutive wk with 5 x 10(7) pooled sperm/50 microL from either young or old broiler breeder males. Sperm penetration (SP) of the PL at the GD was assessed in a random sample of 12 oviposited eggs from each hen group for each day postinsemination, with the remainder of the eggs incubated for 10 d to obtain fertility values. For the main effect of sex, and for age within sex, there were differences in mean SP (7.3 vs 4.8; Y vs O hens; P < 0.02) and fertility (73.7 vs 54.9%; Y vs O hens; P < 0.002) values. Old males had higher mean SP values and fertility (7.2 and 70.6%) than young males (4.8 and 58.0%; P < 0.03 and 0.01, respectively). Following artificial insemination of a constant number of sperm, age of hens appears to contribute more to the decrease in SP and fertility than the age of male broiler breeders. Eggs were obtained from naturally mated broiler breeder flocks from different strains (A and B), lines (male and female), and ages. There was an effect on overall mean SP values due to strain (105.8 vs 78.6 holes per GD area; Strains A and B, respectively; P < 0.0001), and line within Strain B (106.4 vs 50.8 holes per GD; male and female line, respectively; P < 0.0001). There was a quadratic relationship between SP of the PL and age in Strain A with values ranging from 153.3 to 20.0 holes per GD area (P < 0.003). In Strain B, SP holes in the PL decreased in the male line due to age (127.8 to 59.7 per GD; P < 0.01), with an effect of age on the female line also (62.1 vs. 37.8 holes per GD; P < 0.05).

Age Factors↗
PubMed1996

Influence of male broiler breeder dietary energy intake on reproduction and progeny growth.

A study was conducted to test the effects of dietary energy intake on reproduction in genetically similar broiler breeder males and on the subsequent growth of their progeny. Fifty-nine 1-d-old pedigree broiler breeder male chicks were raised to breeding age. At 33 wk of age, 33 males were chosen and placed in one of three groups of 11 males per group and fed either 370, 330, or 290 kcal per bird per d. Each group contained both full and half brothers and had similar 6- and 33-wk mean body weights. There was a significant negative effect of decreased dietary energy intake on sperm concentration and total live sperm per milliliter of ejaculate, whereas there was no significant effect on ejaculate volume or percentage dead sperm per ejaculate. Four groups of hens (21 wk of age) with 18 hens per group, were randomly assigned to each male dietary treatment group. Hens were artificially inseminated with 50 microL neat pooled semen from one of the three male treatment groups. There was a significant linear effect of diet on fertility, with no significant effect on hatch of fertile, hatch of eggs set, or embryonic mortality. There was no effect of sire energy intake on offspring body weights at 0, 3, or 6 wk of age. Hens were similarly artificially inseminated and sperm penetration determined for 9 consecutive d postinsemination. There was a significant quadratic relationship between sperm penetration of the perivitelline layer overlying the germinal disc and day postinsemination for each of the three male treatment groups. In addition, mean sperm penetration was 62.3, 42.9, and 6.6 holes in the germinal disc perivitelline layer for the high, medium, and low energy groups, respectively. Following 16 wk of dietary energy treatment, there was a significant linear effect of diet on mean testes weight, mean testes weight as a percentage of male body weight, and male body weight.

Animals↗
PubMed1996

The male contribution to broiler breeder heat-induced infertility as determined by sperm-egg penetration and sperm storage within the hen's oviduct.

The purpose of the present study was to define the role of the male broiler breeder in heat-induced infertility. Seventy-two Arbor Acres roosters were individually caged at 21 wk of age and divided equally among three heated (H) and three control (C) temperature chambers. Control temperature chambers were held at 21 C. After an 8-wk pretreatment period (20 C), an 8-wk treatment period was conducted in which the temperature in all three of the H chambers was varied from week to week according to the following schedule: Week 1, 27 C; Week 2 through Week 4, 32 C; and Week 5 through Week 8, 21 C. On a weekly basis, semen was pooled by room and inseminated into 12 groups of 10 hens each (2 groups per room). During the 1st wk when males were maintained at 27 C for 12 h, in vivo sperm-egg penetration was reduced by 48% as compared to data obtained when males were maintained at 21 C. Fertility, in vivo sperm-egg penetration, and uterovaginal sperm storage were decreased when semen from males exposed to 32 C was used to inseminate hens as compared to insemination with semen from C males. However, during this same period, the ability of sperm to bind and penetrate the egg, as determined by in vitro sperm-egg penetration, was similar between sperm from C and H males. After lowering the temperature in the H chambers back to 21 C, in vivo sperm-egg penetration as a result to insemination with semen from H males was analogous to results obtained when C males were used for insemination. Immediately after decreasing the temperature in the H chambers, fertilization of eggs by sperm from H males increased to a level similar to that obtained when eggs were fertilized by sperm from C males but then declined again during the later weeks.

Analysis of Variance↗
PubMed1995

Fertility of male and female broiler breeders following exposure to elevated ambient temperatures.

Because elevated ambient temperatures decrease fertility, this study was designed to segregate the male and female contribution to heat stress infertility in broiler breeders. Eighty hens and 16 roosters at 21 wk of age were divided equally among two heat stress (S) and two control (C) temperature chambers. For a 10-wk pretreatment period, all birds were maintained at an ambient temperature of 21.1 C and 40% relative humidity. Following the pretreatment period, birds in the S chambers were acclimated for 1 wk at a constant temperature of 29.4 C after which the temperature in the S chambers was increased to 32.2 C for 8 wk. The temperature in the two C chambers was maintained at 21.1 C. Hens in each chamber were artificially inseminated on a weekly basis with 5 x 10(7) sperm per 50 microL from either C or S males. Egg production, semen volume, spermatocrit, and percentage dead sperm were similar during the acclimation period, even though body temperature was significantly elevated in S birds (41.8 vs 41.3 C). Sperm penetration of the perivitelline layer overlying the germinal disc (GD) was decreased in eggs from hens inseminated with semen from S males compared to eggs from hens inseminated with semen from C males (9.5 vs 23.4 sperm per GD). Following the acclimation period, body temperature remained elevated in the S birds compared to the C birds (42.2 vs 41.3 C). Also, egg production was depressed in the S vs C hens (55.8 vs 82.9%). Semen volume, spermatocrit, and percentage dead sperm were not affected by S treatment. However, when hens were inseminated with semen from S males, sperm penetration of the perivitelline layer overlying the GD and egg fertility were decreased compared to hens inseminated with semen from C males (5.4 vs 14.9 sperm per GD, 45.5 vs 73.8% fertility). In conclusion, the male bird appears to contribute more to heat stress infertility than the female.

Acclimatization↗
PubMed1993

Response of layer breeders to dietary acetylsalicylic acid. 2. Effects on circulating concentrations of prostaglandin F2 alpha.

White Leghorn breeder hens were fed 0, .05, or .40% acetylsalicylic acid (ASA) for either 1 wk or 1 mo. Blood samples were collected 4 h postentrance of an egg into the uterus (baseline) and at oviposition of a hardshelled (HS) egg. Plasma samples were analyzed for prostaglandin (PG) F2 alpha by radioimmunoassay. Peripheral PGF2 alpha concentrations peaked upon oviposition of a HS egg in both ASA-fed hens as well as the controls (0% ASA). The levels of dietary ASA and the duration of time the ASA was administered did not affect baseline or peak PGF2 alpha concentrations. It was concluded that either the timing or route of administration of ASA resulted in the failure of ASA to effectively reduce peak peripheral PGF2 alpha concentrations.

Animals↗
PubMed1993

Response of layer breeders to dietary acetylsalicylic acid. 3. Effects on fertility and hatchability of embryos exposed to control and elevated incubation temperatures.

Because acetylsalicylic acid (ASA, aspirin) is a common antipyretic drug, there has been considerable research on the effects of ASA on mammalian embryonic development. However, very limited research has been conducted on the effects of ASA on avian development and hatchability. The present study investigated the effect of dietary ASA on fertility and hatchability and whether embryos of breeder hens fed ASA, as compared with embryos of hens fed a control diet, would survive elevated temperatures during incubation. White Leghorn layer breeders were fed 0, .025, .050, .100, .200, and .400% ASA for the first 13 mo of egg production. When averaged over 13 mo, hens fed .40% dietary ASA demonstrated a decline in fertility (P < .03), hatchability of fertile eggs (P < .04), and hatchability of eggs set (P < .02). Chicks from hens fed .10% ASA weighed more than chicks from hens receiving 0, .025, .20, or .40% ASA (P < .01). When embryos were incubated at elevated temperatures of 42.8 or 43.3 C for 5.5 to 12 h on Day 16 of incubation, hatchability declined. Also, ASA fed to layer breeders did not improve hatchability of embryos exposed to elevated incubation temperatures when compared with embryos exposed to a control incubation temperature (37.2 C). During Month 9 of production, chicks from hens fed .05 and .10% ASA and exposed to an elevated temperature of 42.8 C for 9 h on Day 16 of incubation weighed more than similarly heat-stressed chicks of hens fed 0, .20, or .40% ASA (temperature by diet interaction, P < .03).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Preference regression modeling of multiple option healthcare delivery systems.

A collection of statistical analysis procedures is applied to the task of estimating relative market shares among different healthcare plans under the offering of multiple options. The results are developed into an interactive spreadsheet for estimating market shares when consumer perceptions of plan features are modified through product redesign or communications strategies.

Attitude to Health↗
PubMed1990

Market segmentation for multiple option healthcare delivery systems--an application of cluster analysis.

Healthcare providers of multiple option plans may be confronted with special market segmentation problems. This study demonstrates how cluster analysis may be used for discovering distinct patterns of preference for multiple option plans. The availability of metric, as opposed to categorical or ordinal, data provides the ability to use sophisticated analysis techniques which may be superior to frequency distributions and cross-tabulations in revealing preference patterns.

Cluster Analysis↗
PubMed1985

Influence patterns and determinant attributes in nursing home choice situations.

Factor analysis revealed that nursing home characteristics fall roughly into two categories: those relating to the care directly provided by the facility and those which are generally unrelated to the quality of care. Not all influences (doctors, discharge planners, retirement home administrators and responsible parties) respond alike to these characteristics. Therefore, a marketing mix directed uniformly to all segments may be suboptimal.

Choice Behavior↗