Body Condition and Winter Supplementation Effect on Weight Change and Reproduction in Spring-calving Beef Heifers PDF Download

Author: Danny F. Coombs
Publisher:
ISBN:
Category : Cattle
Languages : en
Pages : 23

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Author: J. N. Wiltbank
Publisher:
ISBN:
Category : Agriculture
Languages : en
Pages : 48

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Author: Duane Davis
Publisher:
ISBN:
Category : Cattle
Languages : en
Pages : 68

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Author: Benjamin Jennings Renquist
Publisher:
ISBN:
Category :
Languages : en
Pages : 330

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Author: Alex Santos
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages :

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The purpose of these studies was to evaluate the effects of a dietary fat supplementation on growth, reproduction and performance characteristics of replacement beef heifers reared in different management systems (pasture and dry lot conditions). The objectives were (1) to quantify changes in body composition traits and growth performance of replacement beef heifers fed different levels of fat in the supplemented diet, (2) to determine the reproductive performance of heifers supplemented with dietary fat in either a ryegrass pasture system or a dry lot system, and (3) to determine the value of real-time ultrasound technology (RTU) as an alternative technology to assist producers in the decision making process within replacement beef heifer programs. Over the three year study, we observed that both high (3 - 5%) and low (1.5 - 2.5%)levels of dietary fat supplementation of replacement heifers did not have a negative affect in reproductive performance and body composition traits significantly, compared to controls (pasture-base, no supplementation. However, a positive response with respect to some body composition traits was observed in animals fed the higher level of dietary fat in 2004 and 2005 studies. Overall, growth of animals grazing ryegrass outperformed animals supplemented with dietary fat in a dry lot system; yet when dietary fat supplementation was integrated with a ryegrass pasture system, besides the positive effects in body composition traits metabolic changes in relevant reproduction hormones were observed with the addition of dietary fat treatment. Finally, the use of information on body composition traits of replacement beef heifers through the use of real-time ultrasound technology in the decision-making process resulted in a small financial return in these studies. However, the use of this alternative technology in a replacement beef heifer program may have additional value beyond the limited feeding periods reported here. These may include, a greater ability to predict heifer fertility as linked to growth and developmental characteristics (e.g., body composition traits), yet this requires further study.

Author: Michael J. Fields
Publisher: CRC Press
ISBN: 9780849387548
Category : Nature
Languages : en
Pages : 414

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Factors Affecting Calf Crop summarizes the latest information available from leading cattle physiologists and geneticists regarding factors known to influence the production of live calves at weaning. You get practical information on management techniques for improving reproduction efficiency in the herd. You'll also learn about the functioning of the reproductive system and how this may affect reproductive processes in the cow herd. Managers will benefit from a clearer understanding of the factors known to limit efficient reproduction, while veterinarians and other professionals who advise cattlemen will appreciate the substantial reference material and color photographs for defining cow condition scores. Color photographs are also used to illustrate the discussions of testicular thermographies and their applications. Other chapters in the book cover developments in improving reproductive performance of the replacement heifer, the brood cow, and the bull. Topics on reproduction include physiology/endocrinology, the use of growth promotants, genetics and physiological and economic considerations in selecting the age to breed heifers, heritability of fertility, length of the breeding season, prepartum and postpartum nutrition, nursing by the calf, cloning of embryos, and much more.

Author: Richard M. Hopper
Publisher: John Wiley & Sons
ISBN: 1118470850
Category : Medical
Languages : en
Pages : 2206

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Bovine Reproduction is a comprehensive, current reference providing information on all aspects of reproduction in the bull and cow. Offering fundamental knowledge on evaluating and restoring fertility in the bovine patient, the book also places information in the context of herd health where appropriate for a truly global view of bovine theriogenology. Printed in full color throughout, the book includes 83 chapters and more than 550 images, making it the most exhaustive reference available on this topic. Each section covers anatomy and physiology, breeding management, and reproductive surgery, as well as obstetrics and pregnancy wastage in the cow. Bovine Reproduction is a welcome resource for bovine practitioners, theriogenologists, and animal scientists, as well as veterinary students and residents with an interest in the cow.

Author: Devin Lynn Broadhead
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 71

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The objectives of this research were to 1) evaluate the effects of late gestation supplementation, synchronization and creep feeding on cow and calf production traits 2) evaluate the pooled effects of 5 studies involving late gestation supplementation on cow and calf traits. Experiment 1 was a three year study conducted on 8 pastures at the Gudmundsen Sandhills Laboratory. Cows were assigned to 1 of 4 late-gestation supplementation treatments, postpartum progestin or control, and 1 of 2 creep feed treatments to make up a 4 x 2 x 2 factorial arrangement. Calves were followed through to slaughter. Experiment 2 involved 5 studies all conducted at the UNL Gudmundsen Sandhills Laboratory. Studies were pooled based on similar treatments of late gestation supplementation on dormant upland pasture or meadow and different weaning periods. Cow and calf data was analyzed for various traits. Within Experiment 1 all three levels of supplementation increased cow BW and BCS, while the non-supplemented decreased in both. Supplementation treatments did not affect reproductive efficiency such as calving date, calving rate, weaning rate or pregnancy rate. Synchronization had similar results as there were no effects on reproductive measures or calf BW. Supplementation to cows had no effect on calf production traits through slaughter. Creep feeding calves significantly increased calf BW at weaning, yield grade and 12th rib fat. However on a cost/ benefit analysis creep feeding under these conditions added no value on profitability. Different results were achieved with the larger data set of late gestation supplementation. The pooled analysis demonstrated significant effects from supplementation on cow pregnancy rate, adjusted calf BW at weaning but no effect on carcass characteristics. March systems had a higher average pair feed cost but lower cow replacement cost compared to May. The March calving system had higher average net returns based on 9 yrs of market data compared to a May calving system. These studies indicate the effect and importance of late gestation supplementation on cow and calf productivity in a spring calving herd. Cow-calf producers should carefully consider calving system utilization based on their unique production goals.

Author: Keely E. Oswald
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 48

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Book Description
In the majority of management scenarios, it is imperative that beef replacement heifers calve at two years of age. In order to achieve this goal, yearling heifers should reach 60 to 65% of their mature body weight by 13 months of age. Feed costs represent 75 to 80% of the total costs incurred by a beef producer in the development of replacement heifers. At current beef prices, it takes at least three live calves before the heifer development period is paid. Feed costs have become more problematic and volatile in recent years. Increasing pressure for the use of grains in brewing and for ethanol production has inflated feed prices. Demand for grain has also resulted in more ground being taken out of forage production which has resulted in much higher hay prices. However, the increased use of feedstuffs by fermentation industries results in by-product feeds that can be utilized best by beef cattle. Utilization of these by-product feedstuffs by cattle not only results in cheaper feed, and therefore production costs, but also enhances the sustainability of the fermentation industry. The objective of this research was to evaluate puberty onset and subsequent reproductive performance in heifers fed a traditional ration with grass hay to rations in which grass hay was substituted with either grass-seed straw or a grass seed straw-brewer's grain silage. Eighteen heifers (initial body weight = 561±11.4 lbs and age = 278±2.4 d) were randomly assigned to one of three treatment groups: grass hay (HAY), grass seed straw (STRAW), or grass seed straw-brewer's grain silage (SILAGE). Heifers were individually fed twice daily using Calan gates for 22 weeks. Heifers were weighed and 10-ml blood samples were recovered weekly. Plasma was recovered by centrifugation and stored at -20° C until analyzed for progesterone and Anti-Mullerian Hormone (AMH) concentrations. Puberty onset was defined as plasma progesterone exceeding 1 ng/ml. At week 21, heifers were estrous-synchronized using a CIDR-Select Synch protocol. Heifers displaying estrus were inseminated 12 h after onset with one straw of frozen semen. Heifers not displaying estrus were injected with PGF2[subscript alpha] 10 d after the initial PGF2[subscript alpha] injection in the CIDR-Select Synch protocol and subsequently observed for estrus and inseminated as described. Mean ages and weights of heifers were similar (P>0.10) across all treatments at the start of the feeding period. Heifer ages at puberty did not differ (P>0.10) due to treatment. Average daily gain of heifers during the feeding trial fed SILAGE were lower (P0.0005) than heifers fed either HAY or STRAW, However, no differences (p0.10) were found in body weight at puberty onset. However, body weights of heifers fed SILAGE were lower (P0.05) than heifers fed either HAY or STRAW at the starts of the breeding and calving seasons. No differences (P0.10) in services per conception, calving ease scores, calf vigor scores, or calf birth weights were observed between treatments. These results suggest that heifers fed the less expensive, by-product STRAW ration have weight gain and reproductive performance similar to heifers fed a traditional HAY ration. Although heifers fed the SILAGE diet had lighter body weights, a negative impact on reproductive measurements was not observed, suggesting the ration was adequate to support reproductive performance similar to a traditional HAY ration.

Author: Douglas Wade Bawcom
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 40

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