Life Sciences Commons^™

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

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

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

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

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).

G86-820 How To Maximize Income By Managing Days Dry, Jeffrey F. Keown

University of Nebraska-Lincoln Extension: Historical Materials

This guide discusses the benefits of maintaining the optimum calving interval and offers suggestions for accomplishing this reproductive management technique.

Most dairy producers are aware that an optimum calving interval is 365 days. This is a normal lactation length of 305 days with a dry period of 60 days. This interval is often looked at as a goal to strive toward rather than a goal that must be reached to maximize income from the sale of milk.

G86-822 How To Estimate A Dairy Herd's Reproductive Losses, Jeffrey F. Keown

University of Nebraska-Lincoln Extension: Historical Materials

Remedies for herd losses caused by calving interval, dry periods, A.I. performance, and age at first freshening.

One of the major areas of lost income to the dairy producer is in the reproductive performance of the dairy herd. These losses are often overlooked because they are indirect costs. If producers could be given a monthly bill indicating the amount of money that improper reproductive management has cost them, then drastic changes would occur.

The majority of reproductive losses occur in the following areas:

1. Calving interval too long or too short.

2. Dry period too long or too short.

3. …

Natural Tree Reproduction In Urban Environments, John Boyd, Forest Stearns

Field Station Bulletins

Three contrasting urban areas in Milwaukee County were sampled to determine the tree species reproducing and the habitats in which seedlings become established. Habitats most favorable for seedling establishment were shrub hedges and areas along fence lines or adjacent to buildings. Overall, elm and ash were the taxa most successful in establishing seedlings. In the Menomonee Valley, seedlings of boxelder and tree-of-heaven were most abundant with elm and ash close behind, while in Shorewood and Brown Deer, a great variety of seedlings was present. Elm, ash, boxelder, Norway maple, buckthorn, cherry and mountain ash were the most prevalent. Successful seedling …

G85-759 Prominent Congenital Defects In Nebraska Beef Cattle, J. L. Johnson, H. W. Leipold, Donald B. Hudson

University of Nebraska-Lincoln Extension: Historical Materials

This NebGuide describes congenital defects that affect the economic value of beef cattle, and provides recommendations on how to minimize them in breeding programs.

Congenital defects are abnormalities of structure or function present at birth. They may be caused by genetic or environmental factors, or a combination of both. The causes of many defects remain unknown.

Developmental defects may be lethal, semi-lethal, or compatible with life, causing very little effect or only aesthetic effect.

With the increasing use of artificial insemination (AI) in cattle, defects are no longer rare occurrences and are important collectively to the cattle industry. Congenital defects …

G85-755 How To Set Goals For Your Breeding Program, Jeffrey F. Keown

University of Nebraska-Lincoln Extension: Historical Materials

This NebGuide describes how to determine which trait(s) to select for, and how multiple trait selection affects genetic progress.

Dairy producers are often concerned with placing emphasis on different production traits in their breeding program. Selecting on only economically important traits should be the objective of every producer. The use of artificial insemination (A.I.) sires is the most economical and productive way to increase the genetic potential of the herd.

A cow's record is a measure of her genetic potential, which is modified by the environment in which she is kept. Environmental factors that directly influence a cow's record include …

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 …

Environmental Psychology And Great Ape Reproduction, Terry L. Maple

Zoos and Aquariums Collection

At the 1980 Great Ape Infertility Workshop, we concluded that "physical and social environments must be improved if not optimized if great apes are to reproduce satisfactorily ... " In 1982, the trend toward improvement continues and there are some promising signs that reproduction has been enhanced as predicted. The problem of designing and evaluating captive environments which will facilitate interaction, reproduction, appropriate parenting, and socialization is well within the scope of Environmental Psychology. I intend to illustrate the promise of this applied research field in the remarks that follow.

G81-574 Reproductive Diseases In Cattle, Duane Rice

University of Nebraska-Lincoln Extension: Historical Materials

The reproductive diseases mentioned in this NebGuide comprise some of the more common problems confronting the cattle industry today.

Although many advances have been made in controlling reproductive diseases in cattle, serious losses are still common. These losses can be reduced by recognizing the diseases and following the proper management recommendations that are available today. Nearly 50 percent of reproductive failure in cattle is due to infectious diseases, and there are vaccines available that can prevent some of these. Management recommendations may include: 1) vaccines, 2) general sanitation, 3) artificial insemination (AI) or, if a problem is already present, 4) …

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.

G80-537 Reproductive Trace Anatomy And Physiology Of The Cow, Gene H. Deutscher

University of Nebraska-Lincoln Extension: Historical Materials

Knowledge of basic reproduction will help a producer to obtain higher conception rates when using estrous synchronization and/or artificial insemination. The reproductive performance of a cow herd has a great influence on the income and profit realized. A good understanding of the anatomy and physiology of the cow's reproductive system is, therefore, beneficial for successful management. Knowledge of basic reproduction will help a producer to obtain higher conception rates when using estrous synchronization and/or artificial insemination. It will also allow for a better understanding of pregnancy examinations, reproductive diseases and calving difficulty problems.

G80-536 Reproductive Trace Anatomy And Physiology Of The Bull, Gene H. Deutscher

University of Nebraska-Lincoln Extension: Historical Materials

Understanding the anatomy and physiology of the bull's reproductive tract is beneficial for proper management. Good reproductive performance of a bull is necessary to obtain a high percent calf crop. A bull must be fertile and capable of servicing a large number of cows during a short breeding season for optimum production. Understanding the anatomy and physiology of the bull's reproductive tract is beneficial for proper management. A basic knowledge of the reproductive system will also help the producer to understand fertility examinations, reproductive problems and breeding impairments.

Increased Lamb Production With Rams Exposed To Short Daylengths During The Nonbreeding Season, B. D. Schanbacher

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Exposure of rams during the nonbreeding season (anestrous period) to short daylengths will initiate a new sexual cycle characterized by testicular growth, increased mating activity and improved semen quality. Lambing results accumulated from 300 potential matings indicate that rams exposed to artificial photoperiods of 8 hr light and 16 hr darkness for 10 weeks (referred to as rams on short-days) are more fertile than control rams maintained under the relatively long days of spring. When five control rams were penned individually with 30 ewes synchronized with progestogen and PMSG, 67% of the ewes were mated. Eighty-nine percent of the ewes …

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 …

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 …

Acute And Chronic Effects Of Gonadotropin Releasing Hormone On Reproductive Characteristics Of Rams During The Nonbreeding Season, B. D. Schanbacher, D. D. Lunstra

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Acute and chronic effects of gonadotropin releasing hormone (GnRH) administration on reproductive characteristics of 32 rams have been assessed during the nonbreeding season. Rams injected intramuscularly with 50 µg of GnRH had elevated (P<.01)concentrations of serum testosterone and noticeably higher (60%) mating activities when compared to control animals injected with saline. Daily injections of GnRH resulted not only in higher testosterone concentrations and mating activity, but also in increased testes size (P<.05). The apparent change in testicular function may account for the improvement in semen quality which was observed in these animals. Although benefits were only slight for percentages of live sperm, normal sperm and sperm with normal acrosomes, sperm motility was markedly increased (P<.05).

These data suggest that reproductive performance in rams is related to testicular androgen secretion and that a spring decline in those characteristics normally associated with high fertility in the male can be lessened by chronic treatment with GnRH.

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 …

Influence Of Size Of Cone Crop On Diameter Growth Of Engelmann Spruce (Picea Engelmannii Parry), Herbert Hager

T.W. "Doc" Daniel Experimental Forest

The influence of the average annual cone crop of 170 Engelmann spruce trees on the average basal area increments over a period of 23 years was tested in climatically compensated and uncompensated multiple regression models. In addition, three outstanding cone producing trees were analyzed with the climate compensating model. The cone production of the individual trees were analyzed for the effect on each basal area increment without climatic compensation. A multiple regression model with bimonthly climatic parameters for the growing season, yielded the best prediction (R2 = 98%) of annual basal area increment from the independent parameters among which was …

Reproduction In The Wolverine, Gulo Gulo, Philip L. Wright, Robert L. Rausch

Harold W. Manter Laboratory of Parasitology: Faculty and Staff Publications

The reproductive habits of the wolverine, largest of the terrestrial mustelids, have remained largely unknown. Recently Rausch (1953) has concluded that the American and European wolverines belong to the same species (Gulo gulo). In this paper, the reproduction of this species is investigated.

The Structure And Reproduction Of Corn, T. A. Kiesselbach

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

The primary purpose of this paper is to summarize investigations concerning the structure and reproduction of the corn plant (Zea mays L.). Because of wide interest in the reproductive process in connection with breeding and genetic studies the floral development, fertilization, and embryology are especially stressed. The morphology and development of the vegetative organs is also included. The botanical relationship, origin, genetics and breeding of corn are briefly considered.