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Articles 1 - 7 of 7
Full-Text Articles in Agriculture
Artificial Insemination And Fetal Programming In Beef Production Systems, Dempster Christenson
Artificial Insemination And Fetal Programming In Beef Production Systems, Dempster Christenson
Department of Animal Science: Dissertations, Theses, and Student Research
Pregnancy to artificial insemination and late gestation fetal programming of the next calf crop are central to genetic development, reproductive longevity, calf crop productivity, and efficiency of cow/calf ranching. The purposes of this research are to find methods to improve pregnancy rate to artificial insemination, the growth and reproductive health of pregnant heifers, and the productivity of their offspring. In the first of four studies we found that extending the period of progesterone administration in an estrus synchronization protocol did not significantly hasten estrus response or increase pregnancy rate to artificial insemination, but timing of estrus within the melengestrol acetate …
Investigation Of Breeding Objectives And Indexes-In-Retrospect, Hunter F. Valasek
Investigation Of Breeding Objectives And Indexes-In-Retrospect, Hunter F. Valasek
Department of Animal Science: Dissertations, Theses, and Student Research
This thesis presents two projects that investigate the impacts of breeding objectives and indexes-in-retrospect within the beef cattle industry. The first project synthesized how changes due to planning horizon, breeding system, and sale endpoint in the economic breeding goal of cattle influence the relative emphasis of traits as well as the re-ranking of selection candidates. A total of three breeding systems that represent straightbred and crossbred cattle were used along with six planning horizons (2, 5, 10, 20, 30, and 50 yrs.) for both a weaning and slaughter point of sale. The combination of these different breeding objective attributes resulted …
Beef Production Systems In The Nebraska Sandhills, Mckay Erickson
Beef Production Systems In The Nebraska Sandhills, Mckay Erickson
Department of Animal Science: Dissertations, Theses, and Student Research
Four studies were conducted to determine the effectiveness of improving production systems of beef cattle in the Sandhills region of Nebraska. These studies were to determine impacts of modified estrus synchronization protocols, genomic testing heifer calves for longevity, and evaluation of 2 differing calving systems (March or May) for improving biological outcome and improved production. Experiment 1 utilized 180 yearling heifers to determine the effectiveness of a second dose of prostaglandin F2α(PGF) with those females not expressing estrus after an initial 14 d MGA-PG estrus synchronization protocol. The treatment of PGF did increase estrus expression, but did not …
Selective Harvest Methods And Chemical Treatment Of Baled Corn Residue For Utilization In Growing Calf And Dry Cow Diets, Ashley C. Conway
Selective Harvest Methods And Chemical Treatment Of Baled Corn Residue For Utilization In Growing Calf And Dry Cow Diets, Ashley C. Conway
Department of Animal Science: Dissertations, Theses, and Student Research
Three studies were conducted to evaluate baled corn residue using selective harvest method and anhydrous ammonia treatments to assess utility in growing calf and dry cow diets. Baled corn residue was harvested using conventional rake-and-bale (CONV) method, or harvested using the New Holland Cornrower in which either eight rows (8ROW), or two rows (2ROW) of corn stalks were chopped into the windrow with tailings. Bales were either not treated or ammoniated at 5.5% DM. When fed to wether lambs in a mixed ration (65% residue, 30% wet corn gluten feed) to determine digestibility, the 2ROW residue had greater apparent DM, …
Evaluation Of Growth Promoting Implant Strategies And Days On Feed On Finishing Heifer Performance And Evaluation Of Optimal Reimplant Times For Finishing Heifers And Steers, Caitlin Ohnoutka
Department of Animal Science: Dissertations, Theses, and Student Research
Two experiments evaluated the effects of delayed, long-acting coated implants or uncoated implants to non-implanted heifers fed for constant or varying days on feed. In Exp. 1, heifers were implanted with either Revalor-XH on d 1, Revalor-200 on d 1, Revalor-XR on d 1, or Revalor-200 on d 70 compared to non-implanted control heifers when fed for an average of 198 d. In Exp. 2, heifers were implanted with Revalor-200 on d 1 and reimplanted with Revalor-200 on d 100, Revalor-XH on d 1, or not implanted and fed for different days on feed: 151, 165, 179, or 193. Implanting …
Impact Of Shade On Performance And Heat Stress Of Finishing Cattle And Pooled Analysis Of Individually Fed Finishing Trials, Brett A. Melton
Impact Of Shade On Performance And Heat Stress Of Finishing Cattle And Pooled Analysis Of Individually Fed Finishing Trials, Brett A. Melton
Department of Animal Science: Dissertations, Theses, and Student Research
A commercial feedyard trial in Eastern Nebraska evaluated the effect of shade vs no shade on cattle performance, ear temperature, and panting scores. No differences in overall performance (final BW, DMI, ADG, and G:F) or carcass characteristics (HCW, 12th rib fat thickness, marbling, LM area, and calculated YG) were observed. Cattle that were provided shade had lower panting scores and ear temperatures, and greater DMI, compared to cattle that had no shade during heat events. Also, a treatment by hour interaction for movement of cattle occurred for one of the heat events. In comparison, the cool event had greater …
Identifying Breed Effects For Cow Mature Weight, Madeline J. Zimmermann
Identifying Breed Effects For Cow Mature Weight, Madeline J. Zimmermann
Department of Animal Science: Dissertations, Theses, and Student Research
Mature weight (MWT) in beef cattle has increased over the past 30 yr. In general, larger cows are costlier to maintain than smaller cows, and their profitability depends on their production environment. A wide range of beef production environments exist in the United States. There are also a variety of beef cattle breeds that can be chosen and mated to create a type of cow which will be optimally suited to excel in a given environment. However, there remains a need for tools allowing effective comparison among breeds to facilitate such decision making. Unfortunately, estimated progeny differences ( …