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Articles 1 - 15 of 15
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Effect Of Castration On Plasma Luteinizing Hormone Concentrations In Prepubertal Boars, R. J. Kittock, J. E. Kinder, R. K. Johnson
Effect Of Castration On Plasma Luteinizing Hormone Concentrations In Prepubertal Boars, R. J. Kittock, J. E. Kinder, R. K. Johnson
Department of Animal Science: Faculty Publications
Mean concentrations and the occurrence of pulsatile release of luteinizing hormone (LH) were determined in 14-wk-old crossbred boars (50.5 ± 1.5 kg) after bilateral or unilateral castration at 10 wk of age. Blood was collected at 10-min intervals for 5 h. Then gonadotropin releasing hormone (GnRH; 40 / μg) was given and sampling was continued at 5-min intervals for 1 h. Compared with intact boars, bilateral castration increased (P<.001) mean LH (982 ± 56 vs 389 ± 56 pg/ml), pulsatile releases of LH (7.0 ± .6 vs 2.0 ± .6 pulses/5 h) and LH pulse amplitude (617 ± 29 vs 360 ± 58 pg/ml). Unilaterally castrated boars did not differ from intact boars in any of the above measures of LH secretion. Testis weight increased more between 10 and 14 wk of age in the unilateral castrates than in the intact boars (432 ± 42 vs 245 ± 34%; P<.05). Thus, compensatory hypertrophy occurred within 4 wk of castration. Plasma testosterone was lower for bilateral castrates than for intact animals (.1 ± .8 vs 3.6 ± .9 ng/ml; P<.05) while unilateral castrates (3.8 -+ 1.0 ng/ml) and intact boars did not differ. Plasma estradiol concentrations in bilateral and unilateral castrates were not different from levels found in intact boars (1.8 ± 1.8, 8.8 ± 2.1 and 6.0 ± 1.8 pg/ml, respectively). While mean LH after GnRH was higher in bilateral and unilateral castrates than in intact boars (2,588 ± 147 and 2,693 ± 164 vs 1,928 ± 147 pg/ml; P<.01), castration did not affect the highest LH level after GnRH, time of highest level, magnitude of LH change or rate of LH response during the first 15 rain after GnRH. The rate of change of LH from 0 min to time of maximum LH of the bilateral castrates tended to be greater than that in intact boars (b=202 vs 94; P<.10). These data indicate that the negative feedback of gonadal steroids affects LH secretion.
Sow Productivity Comparisons For Four Breeds Of Swine: Purebred And Crossbred Litters, H. R. Gaugler, D. S. Buchanan, R. L. Hintz, R. K. Johnson
Sow Productivity Comparisons For Four Breeds Of Swine: Purebred And Crossbred Litters, H. R. Gaugler, D. S. Buchanan, R. L. Hintz, R. K. Johnson
Department of Animal Science: Faculty Publications
Data were collected from 366 litters produced in a four-breed (Duroc, Yorkshire, Spotted and Landrace) diallel mating system. Purebred and crossbred litters were farrowed during five consecutive (fall and spring) farrowing seasons (fall 1976 through fall 1978). Litters were produced by randomly mating boars of each breed to at least one female of each breed. Litter size and weight at birth, litter size and weight at 42 d and pig survival to 42 d were analyzed. There were significant parity effects for all traits except survival rate, and significant year and season effects for litter size at birth and 42 …
Testicular Development And Endocrine Characteristics Of Boars Selected For Either High Or Low Testis Size , A. P. Schinckel, R. K. Johnson, R. J. Kittock
Testicular Development And Endocrine Characteristics Of Boars Selected For Either High Or Low Testis Size , A. P. Schinckel, R. K. Johnson, R. J. Kittock
Department of Animal Science: Faculty Publications
Thirty-six Landrace x Large White cross boars were selected from litters with either high or low estimated breeding values for 150-d paired testis weight. Blood samples were taken via jugular venipuncture at eight ages (42, 56, 70, 84, 98, 112, 126 and 140 d). At each sampling age, nine blood samples were taken at 30-min intervals. Luteinizing hormone (LH) was determined on the individual serum samples. Serum samples from each boar at each age were pooled and concentrations of follicle-stimulating hormone (FSH), estradiol-17β (E2) and testosterone (T) were determined. Paired testis width, testis length and body weight were …
Relationships Among Measures Of Testicular Development And Endocrine Function In Boars, A. P. Schinckel, R. K. Johnson, R. J. Kittock
Relationships Among Measures Of Testicular Development And Endocrine Function In Boars, A. P. Schinckel, R. K. Johnson, R. J. Kittock
Department of Animal Science: Faculty Publications
Nine blood samples were taken at 30-min intervals from 36 Landrace x Large White boars at each of eight ages (42, 56, 70, 84, 98, 112, 126 and 140 d). Serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T) and estradiol- 17β (E-2) were quantified by radioimmunoassay procedures. The maximum concentration of LH and the age at maximum concentration were predicted for each boar. Variability of LH samples was described for each boar by the pooled within age variance among LH samples and by the number of LH peaks. Measurements of testicular development taken at 140 …
Reproductive Performance For Four Breeds Of Swine: Crossbred Females And Purebred And Crossbred Boars, D. S. Buchanan, R. K. Johnson
Reproductive Performance For Four Breeds Of Swine: Crossbred Females And Purebred And Crossbred Boars, D. S. Buchanan, R. K. Johnson
Department of Animal Science: Faculty Publications
Matings and litters were studied involving all three-breed crosses (sired by purebred boars) and four-breed crosses (sired by crossbred boars) from the Duroc, Yorkshire, Landrace and Spotted breeds. There were 764 female mating records and 161 boars used over five sequential breeding seasons. A sample of pregnant gilts was slaughtered each season and the remainder were allowed to carry their litters to term so that 493 litters resulted. Crossbred and purebred boars and crossbred females were evaluated for their contributions to conception rate (first service and over an 8-wk breeding season), number of services/ conception, litter size and weight at …
Multiple Trait Evaluation Of Bulls For Calving Ease, L. Dale Van Vleck, K. M. Edlin
Multiple Trait Evaluation Of Bulls For Calving Ease, L. Dale Van Vleck, K. M. Edlin
Department of Animal Science: Faculty Publications
Evaluation of bulls for calving difficulty of their calves by a multiple trait, mixed model procedure seems appropriate for a number of reasons. Average calving ease scores and their variances and heritabilities differ according to sex of calf and parity of mother. The multiple trait procedure automatically accounts for differences in averages, variances, and heritabilities. The procedure also allows for the magnitude of herd-year-season effects to be different for four traits as defined by calving difficulty scores when measured on: male birth by a heifer, female birth by a heifer, male birth by a cow, and female birth by a …
Preweaning Survival In Swine: Heritability Of Direct And Maternal Effects, William R. Lamberson, R. K. Johnson
Preweaning Survival In Swine: Heritability Of Direct And Maternal Effects, William R. Lamberson, R. K. Johnson
Department of Animal Science: Faculty Publications
The heritabilities of direct and maternal effects on litter survival to weaning (LS) were estimated from records of 1,243 litters of pigs from the Nebraska Gene Pool population born from 1968 to 1981. Heritabilities were estimated by: (1) weighted least-squares regressions of average survival for litters of sons on average survival for litters of their sire, (2) nested analysis of variance with LS fitted to a model including year-line and sire of litter, (3) weighted least-squares regression of average survival for the litter of daughters on the survival of the litter of their dam and (4) nested analysis of variance …
The Nutritional Value Of High Moisture And Reconstituted Sorghum Grain For Swine, J. D. Crenshaw, E. R. Peo, Jr., A. J. Lewis, B. D. Moser, T. D. Crenshaw
The Nutritional Value Of High Moisture And Reconstituted Sorghum Grain For Swine, J. D. Crenshaw, E. R. Peo, Jr., A. J. Lewis, B. D. Moser, T. D. Crenshaw
Department of Animal Science: Faculty Publications
A growing-finishing experiment involving 150 crossbred swine (replicated by time) and two metabolism experiments involving 36 crossbred barrows were conducted to determine the nutritional value of harvested high moisture (HMSG), reconstituted (RCSG) and dry sorghum grain (DSG) for swine. In Exp. 1, pigs fed HMSG diets gained the same, consumed similar amounts of feed, but less (P<.05) crude protein (equivalent dry matter basis) and had better (P<.05) feed conversion than pigs fed DSG diets.
Effect Of Various Dietary Arginine: Lysine Ratios On Performance, Carcass Composition, And Plasma Amino Acid Concentrations Of Growing-Finishing Swine, L. C. Anderson, A. J. Lewis, E. R. Peo, Jr., J. D. Crenshaw
Effect Of Various Dietary Arginine: Lysine Ratios On Performance, Carcass Composition, And Plasma Amino Acid Concentrations Of Growing-Finishing Swine, L. C. Anderson, A. J. Lewis, E. R. Peo, Jr., J. D. Crenshaw
Department of Animal Science: Faculty Publications
Crossbred growing-finishing pigs (112 barrows, 48 gilts) were used to determine the effect of reducing excess dietary arginine, through feedstuff variation, on performance, carcass composition and plasma amino acid concentrations. Diets contained five, four, three or two times the NRC requirement for arginine. Lysine in all diets was formulated to be equal to NRC requirements, and all diets contained at least 100% of the NRC recommendations for all other essential amino acids.
Relationship Of Lactation Energy Intake And Occurence Of Postweaning Estrus To Body And Back Fat Composition In Sows, D. E. Reese, E. R. Peo, Jr., A. J. Lewis
Relationship Of Lactation Energy Intake And Occurence Of Postweaning Estrus To Body And Back Fat Composition In Sows, D. E. Reese, E. R. Peo, Jr., A. J. Lewis
Department of Animal Science: Faculty Publications
Forty-five crossbred primiparous sows were used to determine the relationship of lactation energy intake and the occurrence of post-weaning estrus to (1) body fat (percentage), (2) lean body mass (LBM) and (3) qualitative and quantitative characteristics of adipose tissue. Sows received 8 (Lo) or 16 (Hi) Meal of metabolizable energy (ME)/d during lactation and 5.4 Meal of ME/d post-weaning.
Effects Of Inbreeding On Milk And Fat Production, Stayability, And Calving Interval Of Registered Ayrshire Cattle In The Northeastern United States, G. F. S. Hudson, L. Dale Van Vleck
Effects Of Inbreeding On Milk And Fat Production, Stayability, And Calving Interval Of Registered Ayrshire Cattle In The Northeastern United States, G. F. S. Hudson, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Inbreeding coefficients of 30,794 registered Ayrshire cows were calculated from relationships between sire and maternal male ancestors. Average inbreeding coefficient of all cows was less than 1% and of the 5,202 inbred cows was 5.4%. Fewer than 2% of inbred cows had coefficients greater than 15%. Percent of inbred cows increased from 23% of cows born in 1972 to 43% in 1980. Over the same period average inbreeding coefficient of all cows increased from 1.2 to 2.0%, but average coefficient of inbred cows decreased from 5.6 to 4.7%.
Effects of inbreeding on first lactation, 305-day, 2x, mature equivalent milk and …
Genetic Trend For Milk Yield From Doe Evaluations In The Northeast United States, K. G. Boldman, L. Dale Van Vleck
Genetic Trend For Milk Yield From Doe Evaluations In The Northeast United States, K. G. Boldman, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Milk production records of 306 Alpine, 72 LaMancha, 170 Nubian, 84 Saanen, and 235 Toggenburg does born in the Northeast from 1972 through 1979 were used to estimate trends of additive genetic value. Estimated transmitting abilities were doubled and averaged for all does born in each year to obtain yearly estimates of genetic value. Genetic trends from regression of yearly mean genetic value on year of birth for Alpine, La- Mancha, Nubian, Saanen, and Toggenburg averaged 11.4, -7.9, 1.9, 14.6, and 11.7 kg per year. Genetic trends were less than theoretically possible, indicating that more effective selection schemes are needed, …
Inbreeding Of Artificially Bred Dairy Cattle In The Northeastern United States, G. F. S. Hudson, L. Dale Van Vleck
Inbreeding Of Artificially Bred Dairy Cattle In The Northeastern United States, G. F. S. Hudson, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Inbreeding coefficients of artificially bred Ayrshire, Guernsey, Holstein, Jersey, and Brown Swiss cows were calculated from relationships between sires and maternal male ancestors. Percentages of inbred cows and average inbreeding coefficients of inbred cows were: Ayrshire, 26 and 11%; Guernsey, 11 and 4%; Holstein, 31 and 1%; Jersey 23 and 2%; and Brown Swiss, 23 and 2%. Percentages of inbred cows and average inbreeding coefficients of all cows increased over time whereas average coefficients of inbred cows decreased over time. These temporal trends may be due in part to having more pedigree information available for cows born in later years. …
Effect Of Suckling And Ovariectomy On The Control Of Luteinizing Hormone Secretion During The Postpartum Period In Beef Cows, M. Garcia-Winder, K. Imakawa, M. L. Day, D. D. Zalesky, Roger J. Kittok, J. E. Kinder
Effect Of Suckling And Ovariectomy On The Control Of Luteinizing Hormone Secretion During The Postpartum Period In Beef Cows, M. Garcia-Winder, K. Imakawa, M. L. Day, D. D. Zalesky, Roger J. Kittok, J. E. Kinder
Department of Animal Science: Faculty Publications
Twenty-two mature pluriparous beef cows were randomly assigned to one of six treatments in a 2 x 3 factorial experiment in order to study the role of suckling and ovarian factors on control of the tonic and episodic release of luteinizing hormone (LH). Twelve cows remained intact (INT) and 10 were ovariectomized (OVX) within 4 days following the day of parturition (Day 0). The suckling intensities were nonsuckled (0), suckled once daily for 30 mm (1) and suckled ad libitum by two calves (2). Blood samples were collected at 1 5-mm intervals for 6 h weekly, from Days 6 to …
Effects Of Excess Arginine With And Without Supplemental Lysine On Performance, Plasma Amino Acid Concentrations And Nitrogen Balance Of Young Swine, L. C. Anderson, A. J. Lewis, E. R. Peo, Jr., J. D. Crenshaw, Win Butler
Effects Of Excess Arginine With And Without Supplemental Lysine On Performance, Plasma Amino Acid Concentrations And Nitrogen Balance Of Young Swine, L. C. Anderson, A. J. Lewis, E. R. Peo, Jr., J. D. Crenshaw, Win Butler
Department of Animal Science: Faculty Publications
Three experiments were conducted to determine the effects of excess arginine on performance, plasma amino acid levels and N balance of young pigs (initial weights 6.9, 7.0 and 10.3 kg, respectively). In a 28-d growth trial, various amounts of arginine (0 to 1.6%) were added to a conventional starter diet.