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Reproduction

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Full-Text Articles in Animal Sciences

Out-Of-Season Births Of Elk Calves In Wyoming, Bruce L. Smith Jan 1994

Out-Of-Season Births Of Elk Calves In Wyoming, Bruce L. Smith

United States Fish and Wildlife Service: Publications

ive out-of-season births of Rocky Mountain elk were documented over a 24-month period at the National Elk Refuge, Wyoming. One of four November neonates was radio-instrumented and subsequently died seven days later due to hypothermia. An April-born calf was killed by a coyote. Supplemental winter feeding of elk at the Refuge may increase the frequency of asynchronous reproduction.


Terrapene Carolina Carolina, Joseph C. Mitchell, Rafael O. De Sá Jan 1994

Terrapene Carolina Carolina, Joseph C. Mitchell, Rafael O. De Sá

Biology Faculty Publications

TERRAPENE CAROLINA CAROLINA (Eastern Box Turtle). REPRODUCTION. Female Terrapene carolina containing oviductal eggs have been recorded in Virginia from 26 May to 25 July (Mitchell, in press. The Reptiles of Virginia. Smithsonian Inst. Press, Washington, D.C.). Other reports of reproduction in Terrapene (see list in Ernst and McBreen 1991. Cat. Amer. Amphib. Rept. 512.1-512.13) indicate that nesting occurs in late spring and early summer throughout its range.


Evaluation Of The Gross Anatomy Seasonal Changes Function And Histology Of The Perineal Gland In The Hispid Cotton Rat, Sigmodon Hispidus, Julie Anne Winchell Jul 1993

Evaluation Of The Gross Anatomy Seasonal Changes Function And Histology Of The Perineal Gland In The Hispid Cotton Rat, Sigmodon Hispidus, Julie Anne Winchell

Biological Sciences Theses & Dissertations

The perinea! gland in the hispid cotton rat, Sigmodon hispidus, is a seasonally cyclic, subcutaneously located organ which is associated with the reproductive system. On gross dissection, the gland possesses a strong attachment to the penis with only loose fascia! connections to the rectum and surrounding muscle and skin. Histologic exam confirms this connection to the reproductive tract and shows the organ to be a compound tubuloacinar gland with a projection leading into the penis. The cyclic hypertrophy and regression of the gland closely parallels that of the testes and seminal vesicles indicating that this cyclicity may be under …


Prediction Of Breeding Values For Twinning Rate And Ovulation Rate With A Multiple Trait, Repeated Records Animal Model, L. Dale Van Vleck, K. E. Gregory, S. E. Echternkamp May 1991

Prediction Of Breeding Values For Twinning Rate And Ovulation Rate With A Multiple Trait, Repeated Records Animal Model, L. Dale Van Vleck, K. E. Gregory, S. E. Echternkamp

Department of Animal Science: Faculty Publications

A genetic correlation near unity between ovulation rate in heifers and later twinning frequency led to consideration of using measures of ovulation rate in heifers for each estrous cycle, beginning at puberty, to increase accuracy of selection for twinning rate. An initial evaluation with a multiple trait animal model for predicting breeding values included six genetic groups: 1) selected Scandinavian bulls, 2) transfers from other populations at the Research Center to a twinning project, 3) early-purchased Holsteins, 4) late-purchased Holsteins, 5) early purchases-other breeds. and 6) late purchases-other breeds. For ovulation and twin measures, heritabilities of .l00 and .070 and …


An Analysis Of External Features As Predictors Of Reproductive Status In Small Mammals, Kenneth Wayne Mccravy Apr 1990

An Analysis Of External Features As Predictors Of Reproductive Status In Small Mammals, Kenneth Wayne Mccravy

Biological Sciences Theses & Dissertations

Reproductive status in specimens of nine populations of seven species of small mammals was evaluated by examining the external reproductive features of nipple size, condition of the pubic symphysis, and vaginal condition and, in males, testis position. Usefulness of these external features in predicting true monthly breeding rates was evaluated by comparing predictions of breeding rates with true rates based on necropsy. Accuracy of predictions of reproductive status of individuals based on single external features and combinations of external features and body measurements was then analyzed at a finer level by comparing those predictions with results of necropsy of the …


Index Selection For Components Of Litter Size In Swine: Response To Five Generations Of Selection, S. M. Neal, R. K. Johnson, R. J. Kittock Oct 1989

Index Selection For Components Of Litter Size In Swine: Response To Five Generations Of Selection, S. M. Neal, R. K. Johnson, R. J. Kittock

Department of Animal Science: Faculty Publications

Selection for an index of ovulation rate (OR) and embryo (fetal) survival rate (ES) to 50 d of gestation (I = 10.6 x OR + 72.6 x ES) was practiced for five generations in a line that was a composite population of the Large White and Landrace breeds of swine. A control line sampled from the same population was selected randomly and mated. Ovulation rate and number of fetuses (FETS) were measured by laparotomy and ES was calculated as FETS/OR. The select line averaged 43 litters by 18 sires and the control line averaged 42 litters by 15 sires per …


Correlated Responses Of Carcass And Reproductive Traits To Selection For Rate Of Lean Growth In Swine, E. R. Cleveland, R. K. Johnson, P. J. Cunningham Oct 1988

Correlated Responses Of Carcass And Reproductive Traits To Selection For Rate Of Lean Growth In Swine, E. R. Cleveland, R. K. Johnson, P. J. Cunningham

Department of Animal Science: Faculty Publications

Mass selection for an index of increased post-weaning average daily gain and decreased backfat thickness was practiced for five generations. Litter size and weight for 221 gilt litters, birth weight and nipple number for 2,242 piglets and weaning weight at 42 d of age for 2,111 pigs were recorded. Carcass measurements were taken on 331 pigs. Differences between means of the lines (select control) were regressed on cumulative selection differential of the index. These regression coefficients were negative (P > .10) for total number born, number born alive, number weaned per litter, nipple number and carcass backfat thickness. Coefficients were …


Effects Of Body Condition On Reproductive Performance Of Range Beef Cows, R.J. Pruitt, P.A. Momont Jan 1988

Effects Of Body Condition On Reproductive Performance Of Range Beef Cows, R.J. Pruitt, P.A. Momont

South Dakota Beef Report, 1988

Mature Simnnental x Angus crossbred cows were fed differing Levels of nutrition from December to May in each of 3 years to create a wide range in cow body condition or fleshiness at the beginning of the calving season (beginning mid-March) and when turned to summer pasture (early May)1 month prior to the beginning of a 60-day breeding season ( early June). Cows that were fleshier in March, May or June cycled earlier and conceived earlier. Being thin in May or June had a more detrimental effect on pregnancy rate for cows that calved late in the calving season. A …


Effects Of Body Condition On Reproductive Performance Of Range Beef Cows, R.J. Pruitt, P.A. Momont Jan 1987

Effects Of Body Condition On Reproductive Performance Of Range Beef Cows, R.J. Pruitt, P.A. Momont

South Dakota Beef Report, 1987

Simnental-Angus crossbred cows were fed differing Levels of nutrition from December to May in each of 3 years to create a wide range in cow body condition or fleshiness at the beginning of the calving season (beginning mid-March) and when turned to summer pasture (early May) 1 month prior to the beginning of the breeding season (early June). Cows that were fleshier in March, May or June cycled earlier. Cows that were fleshier at the beginning of the breeding season calved earlier the following years. For cows that calved Late in the calving season, body condition prior to calving, in …


Genetic Parameter Estimates For Reproductive Traits Of Male And Female Littermate Swine, R. O. Bates, D. S. Buchanan, R. K. Johnson, R. P. Wetteman, R. W. Fent, L. K. Hutchens Mar 1986

Genetic Parameter Estimates For Reproductive Traits Of Male And Female Littermate Swine, R. O. Bates, D. S. Buchanan, R. K. Johnson, R. P. Wetteman, R. W. Fent, L. K. Hutchens

Department of Animal Science: Faculty Publications

Reproductive traits of purebred and crossbred pigs produced in a four-breed diallel mating system using the Duroc, Landrace, Spotted and Yorkshire breeds were collected for five consecutive farrowing seasons (two farrowing seasons/year) beginning in fall 1976. Paternal half-sib heritabilities and genetic correlations for testicular traits (120 boars from 36 sires), serum testosterone (TE) and luteinizing hormone (LH) concentrations before and after treatment with gonadotropin releasing hormone (GnRH; 131 boars from 37 sires) and breeding performance traits (151 boars from 38 sires) were estimated. Heritability estimates were generally small to moderate except for sperm/gram testis (SGT), LH concentrations before (LH0) and …


Effects Of Body Condition On Reproductive Performance Of Beef Cows, P.A. Momont, R.J. Pruitt Jan 1986

Effects Of Body Condition On Reproductive Performance Of Beef Cows, P.A. Momont, R.J. Pruitt

South Dakota Beef Report, 1986

Cows were fed differing nutritional levels before and after calving to create a wide range of cow body condition or fleshiness prior t o calving and at the beginning of the breeding season. Cows that were fleshier prior t o calving and when turned on pasture in early May (30 days prior t o the beginning of the breeding season) had a higher cycling rate in early May, June and July. Cows maintaining or increasing slightly in body condition (precalving to early May) tended to have a higher cycling rate during the breeding season than cows which lost body condition …


Effectiveness Of Albendazole Against Parasites And Cow And Calf Performance, H.L. Miller, J. Berthelsen, B.A. Petitjean, R.H. Haigh Jan 1986

Effectiveness Of Albendazole Against Parasites And Cow And Calf Performance, H.L. Miller, J. Berthelsen, B.A. Petitjean, R.H. Haigh

South Dakota Beef Report, 1986

Albendazole was utilized in drench and feed additive form to determine its effectiveness against parasite control, cow weight and conception rate and calf weaning weights. Fecal oocyte number was decreased by administration of Albendazole. Calf weaning weights from treated cows were heavier the first two years (14.5 lb for heifers and 10.5 lb for bulls) but decreased the third year (13 lb and 6 lb for heifers and bulls, respectively). Conception rates were similar between the two groups, with the only difference occurring the third year when control cows had a higher conception rate from the second AI than treated …


Effects Of Level Of Energy Supplement In Early Winter And Level Protein After Calving On Beef Cows Grazing Native Range, R.J. Pruitt Jan 1986

Effects Of Level Of Energy Supplement In Early Winter And Level Protein After Calving On Beef Cows Grazing Native Range, R.J. Pruitt

South Dakota Beef Report, 1986

Simmental-Angus crossbred cows grazing native range near Cottonwood, SD, were fed two precalving levels of energy supplement and two postcalving levels of protein supplement. Cow weight change and reproductive performance were similar for all treatments. Although calves from cows supplemented with higher levels of energy gained faster from birth to early May, gains to weaning were similar for all treatments.


Effects Of Adding Fat To The Sow Lactation Diet On Lactation And Rebreeding Performance, G. C. Shurson, M. G. Hogberg, N. Defever, S. V. Radecki, E. R. Miller, Win Butler Jan 1986

Effects Of Adding Fat To The Sow Lactation Diet On Lactation And Rebreeding Performance, G. C. Shurson, M. G. Hogberg, N. Defever, S. V. Radecki, E. R. Miller, Win Butler

Department of Animal Science: Faculty Publications

One-hundred-three multiparous sows were randomly assigned to one of two lactation diets containing either no supplemental animal fat (C) or 10% added fat (F) during two seasons, summer (S) and winter (W), in a 2 X 2 factorial arrangement of treatments. Sows were placed on their respective dietary treatments 1 wk prior to farrowing and were fed these diets ad libitum throughout the 28-d lactation period. Weekly feed intake and total feed intake were not affected by diet or season, while weekly metabolizable energy (ME) intake tended to be higher during wk 1 and 3, and was higher (P<.04) during wk 2 for sows fed diet F. Sow weight loss from farrowing to 21 d of lactation and to weaning (28 d) were unaffected by diet or season. Average pig birth weight was .15 kg higher (P<.O1) for pigs born during S compared with those born in W. Sows receiving diet F had heavier litters at 21 d (P<.01) and heavier average pig 21-d weights (P<.O1). This was primarily due to the 13.1% increase (P<.04) in estimated milk yield and the higher fat concentration (P<.O01) of milk consumed by the pigs nursing sows fed diet F. Interval between weaning and re-breeding was shortened by 5.9 d (P<.01) for sows during W than during S, and tended to be lower for sows fed diet F (7.3 d) compared with that of sows fed diet C (9.7 d). Farrowing percentage was unaffected by diet but tended to be increased during W (78.9%) compared with S (65.1%). No differences between mason or diet were noted on number of pigs born or number of pigs born alive in the subsequent parity. No diet • season interactions were observed, except for crude protein concentration of sow's milk, which was higher in milk from sows fed diet C during season W (P<.04).


Testicular Growth In Boars Of Different Genetic Lines And Its Relationship To Reproductive Performance , Allan Schinckel, R. K. Johnson, R. A. Pumfrey, Dwane R. Zimmerman May 1983

Testicular Growth In Boars Of Different Genetic Lines And Its Relationship To Reproductive Performance , Allan Schinckel, R. K. Johnson, R. A. Pumfrey, Dwane R. Zimmerman

Department of Animal Science: Faculty Publications

Testicular growth of 377 boars was compared by obtaining in situ measurements of testes width and length and excised tissue weights. Two experiments involved a line selected nine generations for ovulation rate (OR) and a control line (CL), and two experiments contained boars of the OR line and two other lines; WL, a Large White-Landrace cross, and a line founded by crossing lines OR and CL and selected six generations for increased average daily gain and decreased backfat (LG line). In situ testes measurements were similar for the OR and CL lines and were curvilinearly related to age. The LG …


The Relationships Between Plasma Progesterone And Lh And The Numbers Of Corpora Lutea And Embryos In Purebred And Crossbred Gilts, R. P. Wettemann, R. K. Johnson, I. T. Omtvedt Jun 1980

The Relationships Between Plasma Progesterone And Lh And The Numbers Of Corpora Lutea And Embryos In Purebred And Crossbred Gilts, R. P. Wettemann, R. K. Johnson, I. T. Omtvedt

Department of Animal Science: Faculty Publications

Relationships between plasma progesterone and luteinizing hormone (LH) and the numbers of corpora lutea and embryos were determined in 133 8-month-old purebred Duroc, Hampshire and Yorkshire gilts and two-breed crosses among the three breeds. The numbers of corpora lutea and normal embryos were determined at slaughteronday 30.8 ± .2 of pregnancy, and progesterone and LH were quantified in plasma obtained the previous day. Progesterone concentrations in plasma were influenced by sire (P<.10), breed of dam (P<.05) and breed of sire x breed of dam (P<.05). Hampshire gilts had higher concentrations of progesterone in plasma than did Durocs (P<.05) and Yorkshires (P<.01). None of the effects in the model was significant for LH. Plasma progesterone and LH had heritability estimates of .48 ± .41 and .29 ± .40, respectively. Most genetic and phenotypic correlations of plasma progesterone and LH with other traits were small. These data indicate that progesterone concentrations in plasma at 30 days of pregnancy are not a satisfactory predictor of the numbers of corpora lutea and embryos. The differences in plasma progesterone between breeds illustrate the need to consider the breed of gilts when selecting animals for the study of luteal function or physiological factors that may influence progesterone concentrations in plasma.


An Analysis Of The Dependency Structure Between A Gilt's Prebreeding And Reproductive Traits. I. Phenotypic And Genetic Correlations, L. D. Young, R. K. Johnson, I. T. Omtvedt Apr 1977

An Analysis Of The Dependency Structure Between A Gilt's Prebreeding And Reproductive Traits. I. Phenotypic And Genetic Correlations, L. D. Young, R. K. Johnson, I. T. Omtvedt

Department of Animal Science: Faculty Publications

This study involved the records of 339 purebred Duroc, Hampshire and Yorkshire gilts and 192 two-breed cross gilts resulting from matings among the three breeds. The primary purpose of this paper was to investigate the relationship of prebreeding traits, including the growth of the gilt and her littermates, with subsequent measures of reproduction. Heritabilities were estimated for several traits and in general the estimates were somewhat higher than most estimates in the literature. Genetically, all measures of growth were favorably and moderately to highly correlated to ovulation rate, with the relationship being stronger for traits measured late in growth as …


An Analysis Of The Dependency Structure Between A Gilt's Prebreeding And Reproductive Traits. Ii. Principal Component Analysis, L. D. Young, R. K. Johnson, I. T. Omtvedt Apr 1977

An Analysis Of The Dependency Structure Between A Gilt's Prebreeding And Reproductive Traits. Ii. Principal Component Analysis, L. D. Young, R. K. Johnson, I. T. Omtvedt

Department of Animal Science: Faculty Publications

Seventeen variables measured before breeding and three measures of reproduction were taken on 339 purebred Duroc, Hampshire and Yorkshire gilts and 192 two-breed cross gilts resulting from matings among these breeds. Eight principal components accounted for 90% of the dependency structure existing among the 17 traits measured before breeding. Two principal components accounted for 97% of the dependency structure existing among the three reproductive traits.

The first principal component (PCll) from the prebreeding traits was a general measure of growth ability and accounted for 28% of the variation in the 17 measurements. The second principal component (PC12) contrasted slow growing …


Reproductive Performance Of Swine Bred To Produce Purebred And Two-Breed Cross Litters, L. D. Young, R. K. Johnson, I. T. Omtvedt Dec 1976

Reproductive Performance Of Swine Bred To Produce Purebred And Two-Breed Cross Litters, L. D. Young, R. K. Johnson, I. T. Omtvedt

Department of Animal Science: Faculty Publications

These data included the records of 818 purebred gilts and sows of Duroc, Hampshire and Yorkshire breeding mated to produce all purebreds and all possible two-way crosses. A total of 212 gilts were slaughtered 30-day postbreeding (72 purebred matings and 140 crossbred matings) to evaluate ovulation rate, number of live embryos, average embryo length and embryo survival rate. A total of 450 litters (161 purebred and 289 crossbred) were farrowed to evaluate litter size, litter weight and average pig weight at O, 21 and 42 days postfarrowing. Litters were farrowed in the spring and fall of 1971 and 1973 and …


Reproduction And Hematology Of The Cache Elk Herd, Thomas B. Follis May 1972

Reproduction And Hematology Of The Cache Elk Herd, Thomas B. Follis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The initial three years of a 10-year reproductive study of elk involved three major phases. A fourth was added because of convenience. Objective 1 was to ascertain pregnancy rates in yearling and mature elk by rectal palpation, associate these rates with subsequent fall cow/calf ratios, and to test concurrently an ultrasonic fetal heart detector. Rectally observed anatomical changes in gravid uteri of cattle were directly applicable to elk. Ultrasonic detections of pregnancies in elk and deer were unsuccessful.

Pregnancy rates in the 1969-70 winter of 100 and 0 percent, respectively, for 19 adult and five yearling elk were associated with …


Asexual Reproduction In Planaria Characteristics Of The Inhibitor(S), Linda Gail Sheffield Aug 1970

Asexual Reproduction In Planaria Characteristics Of The Inhibitor(S), Linda Gail Sheffield

Theses and Dissertations

A study was made of the postulated fission-inhibiting substance located in the cephalic region of Dugesia dorotocephala. Rearing decapitated planaria in four different concentrations (25, 50, 75 or 100 ug/ml) of head or whole body extract resulted in a positive correlation between the inhibition of fission rate and the concentration of extract. The difference in inhibitory activity between the two types of extracts was three percent at maximum. The inhibitory substance was partially inactivated at 60° C. There was a direct correlation between the length of time that the extract was heated and the inactivation of inhibitor. The active substance …


Reproductive Biology Of Thais Emarginata (Deshayes, 1839) And Thais Canaliculata (Dulcos, 1832), Roy Seamands Houston Jan 1970

Reproductive Biology Of Thais Emarginata (Deshayes, 1839) And Thais Canaliculata (Dulcos, 1832), Roy Seamands Houston

University of the Pacific Theses and Dissertations

Thais emarginata (Deshayes, 1839) and Thais canaliculata (Dulcos, 1832), are two common Pacific coast gastropods (Family: Muricidae). T. emarginata is found in semi-protected rocky areas from Alaska to Baja California, while T. canaliaulata occurs in quiet bays from Alaska to Monterey Bay, California (Ricketts and Calvin, 1966). Both species occur on rocks and jetties where they can be seen feeding upon barnacles and young mussels. Despite the abundance of these species their reproductive biology has not been examined.

In the present study, the following aspects of the reproductive biology of T. emarginata and T. canalieulata are presented: Relationship of gonadal …