Growth Hormone as a Predictor of Future Performance in Beef Females

Previous work at this station has established a need for predictors of cow efficiency available at weaning or yearling ages. While the weaning weight of a cow\u27s calf has relatively high accuracy in predicting the efficiency of the dam (60 to 70%), the weaning weight of the cow has only a 1% accuracy. This study was undertaken to determine if levels of circulating growth hormone measurable at young ages would provide a useful means of predicting cow efficiency and other measures of cow performance

Effects of Mating and Management Systems on Beef Production

In recent years there has been increased interest in crossbreeding of beef cattle and with the introduction of new breeds from the European continent increased interest in the use of larger and/or higher milking breeds in these crossbreeding systems. With the expected increase in nutrient requirements for maintenance and milk production associated with increased size of cow and increased milk production, changes in management practices need to be evaluated. This project was designed to evaluate the Simmental-Hereford and the Angus-Hereford two breed rotations and the straightbred Hereford, with all three groups receiving either usual herd management (regular) or a higher level of management consisting of a higher energy level for developing replacement heifers during their first winter and a flush each year at breeding time extending from 30 days prior to the breeding season and carrying 20 days into the breeding season (super)

The Effects of Mating and Management Systems on Beed Production Angus-Charolais Crossbreeding Project

Angus and Charolais heifers purchased in 1968 as weaning calves were used to initiate a crossbreeding project at Brookings. In phase I of this project these heifers were mated by artificial insemination to either an Angus or Charolais bull to produce straightbred Angus, straightbred Charolais, Angus x Charolais and Charolais x Angus calves. (Crosses are denoted in this report with breed of sire listed first.) Three such calf crops have been produced. The heifers from these three calf crops are being used in phase II of the project which consists of a long-term comparison of straightbred and crossbred cows in two environments, pasture and drylot. Individual feed consumption from weaning through the duration of the project is being obtained on heifers assigned to the drylot portion of the study. In addition, individual feed consumption from weaning to slaughter will be measured on all offspring from phase II drylot cows

Crossbreeding Effects on Growth and Carcass Traits of Beef Calves

The cow-calf efficiency project described elsewhere in this bulletin (A.S. Series 75-42) required the production of straightbred and crossbred heifers sired by two bulls, one each from the Angus and Charolais breeds. The purpose of this study was to summarize growth and carcass data from these first crosses. Because the breeds are represented by only one sire, breed comparisons should not be made from these data

Annual Crossbreeding Report for South Dakota Livestock Production Records Association

Each year since 1970 weaning weight records from member herds of the Production Records Association have been used to prepare a crossbreeding summary for use by members and other cattlemen in the formulation of individual breeding programs. This report presents the five year summary which includes the 1974 calf crop

Effect of Temporary Calf Separation on Day of First Service and Conception at First Service

Results of several experiments have indicated the possible effectiveness of temporary calf separations from the cow, both in bringing cows into estrus early and in some cases improving conception rate. It has been demonstrated that frequency of lactation affects the reproductive ability of the cow and it is thought these temporary separations might be involved in this manner. The technique is a part of one of the currently used research methods in estrus synchronization and appears to be useful in conjunction with the hormone treatment. This study was undertaken to determine if calf separation technique would be useful when synchronization was not being attempted

Weaning Weight Summary for South Dakota Livestock Production Records Association Member Herds Using Crossbreeding

The primary objective of this study was to provide members of the Production Records Association an analysis of the weaning weights of various crossbreds produced in member herds. The results should form an important part of the total information needed by members and other cattlemen to formulate individual breeding programs

Predicting Beef Palatability

The search for factors influencing the palatability of beef continues. The relative importance of variables in the USDA quality grading system that currently predicts acceptability and palatability has been questioned. The effect of marbling on palatability is one of the more controversial aspects. Marbling is one of the prime factors in determining the quality grade of a beef carcass and researchers have shown that other variables may play an equal or more important role influencing the eating quality of beef. The purpose of this study was to evaluate the accuracy of commonly-used predictors of palatability and to consider the possible influence of other carcass measures as predictors of palatability. Palatability, as defined in this study, was measured by the subjective taste panel scores for flavor, juiciness and tenderness. Tenderness mas measured objectively with the Warner-Bratzler shear instrument

Evaluation of GoGirlGo!; A practitioner based program to improve physical activity

Background: GoGirlGo! (GGG) is designed to increase girls’ physical activity (PA) using a health behavior and PA-based curriculum and is widely available for free to afterschool programs across the nation. However, GGG has not been formally evaluated. The purpose of this pilot study was to evaluate the effectiveness of the GGG curricula to improve PA, and self-efficacy for and enjoyment of PA in elementary aged girls (i.e., 5-13 years). Methods: Nine afterschool programs were recruited to participate in the pilot (within subjects repeated measures design). GGG is a 12-week program, with a once a week, one-hour lesson with 30 minutes of education and 30 minutes of PA). Data collection occurred at baseline, mid (twice), post, and at follow-up (3-months after the intervention ended). PA was assessed via accelerometry at each time point. Self-efficacy for and enjoyment of PA was measured using the Self-Efficacy Scale and the Short-PA enjoyment scale and was assessed at baseline, post, and follow-up. Fidelity was assessed at midpoint. Results: Across all age groups there was a statistically significant increase in PA. Overall, on days GGG was offered girls accumulated an average of 11 minutes of moderate-to-vigorous PA compared to 8 minutes during non-GGG days. There was a statistically significant difference in girls’ self-efficacy for PA reported between baseline and post, which was maintained at follow-up. An improvement in enjoyment of PA for girls was found between baseline and follow-up. According to fidelity assessment, 89% of the activities within the curriculum were completed each lesson. Girls appeared to respond well to the curriculum but girls 5-7 years had difficulties paying attention and understanding discussion questions. Conclusions: Even though there were statistically significant differences in self-efficacy for PA and enjoyment of PA, minimal increases in girls’ PA were observed. GGG curricula improvements are warranted. Future GGG programming should explore offering GGG every day, modifying activities so that they are moderate-to-vigorous in intensity, and providing additional trainings that allow staff to better implement PA and improve behavior management techniques. With modifications, GGG could provide a promising no-cost curriculum that afterschool programs may implement to help girls achieve recommendations for PA

Evaluation of Cow-Calf Efficiency to Weaning

There has been a great deal of interest in recent years in the relationship between cow size and efficiency. Researchers have determined that maintenance feed requirements are greater for large cows. This finding has furthered the belief that efficiency through weaning is highly dependent upon cow size. It must be pointed out, however, that other studies have generally shown heavier cows produce heavier calves at weaning. It is the purpose of this report to examine feed requirements to produce a unit of weaning weight with regard to size and breed of cows