Download or read book Biostatistical Analysis of Factors Influencing Lactation Performance of Range Cows and Weaning Weights of Their Calves microform written by Sarah Louise Butson and published by National Library of Canada. This book was released on 1981 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation was carried out to examine trends in lactation performance and factors influencing milk traits and calf weaning weight among range beef cattle. Cows representing four beef and dairy-beef breeds and lines from the University of Alberta beef herds ranging in age from 2 to 10 years of age were used in the study. June and September measurements of milk and constituent percentages were taken on 206 and 242 cows in 1976 and 1977 respectively. Age and breed of dam, and age and sex of calf were recorded. Other variables examined were cow weight changes during gestation and lactation and birthweights, weaning weights and preweaning ADG of their calves. Milk variables and calf weaning weights were the traits studied. In Chapter I the lactation performance of the four breed groups of dams was examined. Results indicated that crossbred cows with dairy breed ancestry yielded more milk and were more persistent than a purebred traditional beef breed. Trends between breeds for constituent percentage production were less noticeable although the dairy crossbreds tended to produce less butterfat% than the purebreds. In Chapter II factors influencing milk and constituent yields were investigated using the multiple regression technique in Chapter II. Stepwise regressions involving age and breed of dam accounted for between 34.0% and 44.0% of the variance in any of the milk or constituent yields. Full and restricted regression models allowed the introduction of independent variables after adjusting for age and breed of dam effects. Calf preweaning ADG showed a high association with milk yield variables. Other factors such as calf birthweight and cow weight changes however did not account for a significant proportion of the variance in any one milk or constituent yield variable. Because associations and correlations between milk yield and calf ADG were significant but only moderately high, all factors influencing weaning weights of range calves were examined in Chapter III. Regression analysis indicated that age and breed of dam effects accounted for an average of 47% of the variance in calf weaning weight. When age and breed of dam were not considered, milk or constituent yields accounted for approximately 40% of weaning weight variance. However, milk variables still accounted for up to 10% of the variance after accounting for the effects of age and breed of dam. Calf birthweight and cow weight changes had minor effects on calf weaning weight. As a significant proportion of the variance in weaning weight was accounted for by milk variables, which in turn are largely a reflection of the breed of dam, it was concluded that selection for increased lactation performance and the introduction of dairy breeds into the breeding program of a beef herd can effect meaningful increases the weights of calves weaned.
Download or read book Factors Influencing Cow Performance and Intake written by Justin W. Adcock and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT FACTORS INFLUENCING COW PERFORMANCE AND INTAKE Two studies were conducted to determine how weaning system, residual feed intake (RFI), and residual average daily gain (RADG) affect cow performance and intake. In Study 1, a two-year study was conducted using Angus and Simmental X Angus heifers (n=114) to evaluate how weaning system (early weaning (EW) vs. normal weaning (NW)) affects cow-calf performance and intake. All cows with male calves were early weaned at 130 d while cows with female calves were normal weaned at 200 d. These animals were then evaluated for individual intake at 60 d, 120 d, 180 d, and 240 d postpartum. Weigh-suckle-weigh (WSW) was used to determine milk production for the lactating periods. BW, Hip height, body condition score (BCS, 1-9 scale), and backfat via ultrasound were measured. No differences (P > 0.05) were noted in the 60 and 120 d postpartum cow measurements, but calf BW did differ (P 0.05) with male calves being heaver. At 180 d postpartum cows with their offspring early-weaned had increased (P
Download or read book Some Factors Affecting Weaning Weights and Weaning Scores in Beef Calves written by James S. Brinks and published by . This book was released on 1957 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preweaning Performance of Range Beef Calves and Factor Analysis of Prebreeding Traits of Cow and Offspring written by Benjamin Kwadjo Ahunu and published by . This book was released on 1985 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of Some of the Factors Influencing the Birth and Weaning Weights of Beef Calves written by Keith Edward Gregory and published by . This book was released on 1949 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Impact of Increasing Level of Milk Production on Cow and Calf Behavior and Performance in the Nebraska Sandhills written by Selby L. Boerman and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Selection for increased milk production across the United States has resulted in variable cow and calf production responses. Better understanding of calf nursing and grazing behaviors may provide opportunities to help estimate how milk and grazed forage intake influence variability in calf performance. In a 2-yr study, cow-calf pairs (n = 65) were equipped with neck collars containing global positioning system (GPS) units to validate the efficacy of high-frequency GPS data to accurately identify calf nursing events and grazing behavior. Data were collected during 3-wk tracking periods during early lactation (calf age 65.4 ± 10.0 d; EARLY) and late lactation (calf age 162 ± 22.3 d; LATE). Calf behavior was visually observed for a total of 350 hrs and was used in a training dataset for a random forest (RF) classification model. Out of bag (OOB) estimates of individual behaviors indicated relatively low misclassification error rates, less than 4%, suggesting that high frequency GPS tracking can be used to effectively classify calf nursing and grazing behaviors. Behavior prediction results in this study match ranges reported in previous literature, supporting the efficacy of this technique to assess behavior in beef calves. In a 2-yr study, crossbred cow-calf pairs (n = 118) from March- and May-calving herds were used to determine the impact of increasing total milk production on cow body weight (BW), body condition score (BCS), reproductive performance, calf BW, and calf average daily gain (ADG). On approximately 30, 60, 90, 120, and 210 d postpartum, individual cow 24-h milk yield was estimated with weigh-suckle-weigh techniques. Milk area under the curve (AUC) values were calculated and data were analyzed using linear regression analysis. Cow BW, BW change, and reproductive performance were not (P > 0.12) associated with milk AUC, except for a tendency (P = 0.09) for lower BW at breeding. At weaning, cow BCS was negatively associated (P = 0.09) with increasing milk AUC but was not associated at any other physiological stage. A significant positive association with calf average daily gain (ADG) was observed from birth to age 120 d and a tendency (P = 0.09) for a positive association was observed from age 120 d to weaning. Steer ADG in the finishing phase was not (P = 0.63) associated with dam milk production. In this environment, increasing milk production had a positive increase in calf growth during the pre-weaning phase without any negative impacts on overall cow-calf production.
Download or read book Factors Affecting the Weaning Weight of Range Calves written by Fentress McCoughan Peacock and published by . This book was released on 1956 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Factors Affecting the Weaning Weight of Range Calves written by Fentress McCoughan Peacock and published by . This book was released on 1956 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cow Weights and Other Factors Affecting Calf Weaning Weight written by Charan Chantalakhana and published by . This book was released on 1968 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stochastic Systems Model Assessment of Historical Cow calf Biological and Economic Efficiency for Different Mature Cow Weight and Peak Lactation Combinations in the Kansas Flint Hills written by Dustin Grant Aherin and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A stochastic, individual based systems simulation model describing U.S. beef cow-calf production was developed. Accounting for genetics, nutrition, reproduction, growth, health, and economics, allows analysis of various scenario outcomes encompassing different genetic, management, and marketing strategies. The model's stochastic nature enables consideration of biological variation and probabilistic risk, while the systems design accounts for time delays and complex, prolonged feedback structure, all inherent to beef production. Any number of production years and iterations can be simulated. These capabilities make it ideal for decision analysis and assessment of long-run outcomes regarding a multitude of metrics simultaneously. Parameterizing the model to match Kansas Flint Hills production and economic conditions for the years 1995 through 2018, 32 breeding systems with different genetic combinations for mature cow weight and peak lactation potential were simulated 100 iterations each. Sire mature cow weight genetics ranged from 454 kg to 771 kg in 45 to 46 kg increments. Sire peak lactation genetics were considered at 6.8, 9, 11.3, and 13.6 kg/d for all eight mature cow weights. Retaining replacement females, the breeding herd size goal was 100 animals. Model decision rules aimed to meet individual animal nutrient requirements. Utilizing model results for the years 2000-2018, three different validation procedures were applied. A six person panel with combined expertise spanning veterinary medicine, animal breeding and genetics, ruminant nutrition, agricultural economics, and beef production modeling reviewed model output in both absolute and comparative scenario terms. Separately, raw model results were assessed against actual historical cow-calf production data. Finally, exploratory factor analysis was applied to interpret the underlying factor scores of model output relative to real-world cow-calf production data. In cow-calf production, biological and economic efficiency are not perfectly synonymous. Research simultaneously assessing both the biological and economic efficiency of different mature cow weight and peak lactation combinations for twenty-first century cow-calf production is scarce to non-existent. Aggregating simulation results for the 2000 through 2018 production years, under the specific parameters previously described, larger, heavier milking cows exceled in kilograms weaned per cow exposed, while kilograms weaned per net energy for maintenance (kg/Mcal*100) favored smaller, heavier milking cows. Assuming no price differentiation between weaned calves from different breeding systems, 454 and 499 kg mature cow weight with 13.6 kg/d peak lactation had the highest median annual enterprise return on investment (fed ration, pasture, replacement, and interest expenses) at 8.9 and 7.4 percent, respectively. Applying the assumptions that herds comprised of 454 and 499 kg mature cow weight with 13.6 kg/d peak lactation do not exist and that all weaned calves from 454 kg mature cow weight breeding systems receive a small frame price discount, the 544 kg mature cow weight-13.6 kg/d peak lactation combination generated the greatest median annual return on investment at 7.0 percent. Several combinations of 499, 544, 590, and 635 kg mature cow weights with 11.3 or 13.6 kg/d peak lactation produced a median annual return on investment between 4.1 percent and 5.4 percent.
Download or read book Factors Affecting the Relationship Between Calving Interval of Cows and Weaning Weights of Calves written by Philip Erich Doren and published by . This book was released on 1982 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Agrindex written by and published by . This book was released on 1995 with total page 1064 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ILCA Bulletin No 23 January 1986 written by International Livestock Centre for Africa and published by ILRI (aka ILCA and ILRAD). This book was released on with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1984 with total page 1086 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1973- include the following subject areas: Biological sciences, Agriculture, Chemistry, Environmental sciences, Health sciences, Engineering, Mathematics and statistics, Earth sciences, Physics, Education, Psychology, Sociology, Anthropology, History, Law & political science, Business & economics, Geography & regional planning, Language & literature, Fine arts, Library & information science, Mass communications, Music, Philosophy and Religion.
Download or read book Comprehensive Dissertation Index Agriculture written by and published by . This book was released on 1984 with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt:
