Effects of Post-weaning Development Regimen on Reproduction Performance of Beef Heifers from First to Second Pregnancy PDF Download

Author: Jay D. Olsen
Publisher:
ISBN:
Category : Cattle
Languages : en
Pages : 152

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Author: Jay D. Olsen
Publisher:
ISBN:
Category : Cattle
Languages : en
Pages : 0

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Author: Maggie K. Bloomsburg
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 136

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Book Description
Cattle in the Pacific Northwest graze a variety of forages which vary in quality. The effects of forage quality on heifer reproductive development and fertility is still under investigation. Therefore, the first objective was to investigate the effects of grazing different quality forages preweaning and postweaning on reproductive traits and feed efficiency in heifers. Although nutritional differences were present, pre- and postweaning treatments did not affect reproduction. This indicates different qualities of forage present in Idaho may be utilized for heifers. Feed costs represent a large portion of cattle producers' expenses. Selecting for feed efficiency allows producers to capitalize on these expenses. However, the effects of selecting for efficiency on reproduction is still undetermined. The second objective was to study the relationship between feed efficiency and reproductive development and fertility. No differences in reproductive traits were detected among heifers ranked as efficient, average or inefficient at utilizing feed for growth.

Author: David J Patterson
Publisher: Elsevier Health Sciences
ISBN: 032326137X
Category : Medical
Languages : en
Pages : 210

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The latest information on heifer development in beef cattle for the food animal practitioner! Topics include rebuilding the US cowherd, physiology and endocrinology of puberty, nutritional development and the target weight debate, long-term reproductive health, effect of prenatal programming on development, economics of development, synchronization of estrus and ovulation, post breeding heifer management, management strategies for adding value to heifers, and more!

Author: Everett Dennis Loukonen
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 248

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Author: Amanda Jillian Cain
Publisher:
ISBN:
Category :
Languages : en
Pages : 102

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The objective of the present study was to evaluate the effects of low input development protocols on Southeastern replacement beef females and their offspring. Fall and spring calving crossbred beef heifers managed through one of two heifer development programs (low input, LOW or conventionally developed, CON) were evaluated for metrics of uterine artery hemodynamics, patterns of heifer and offspring growth, postpartum reproductive performance, and economic efficiency. There were significant treatment × season (P = 0.0001) and season × day (P = 0.003) interactions on heifer body weight (BW) during gestation. There was a season × day interaction on total blood flow (TBF; P = 0.05) whereby TBF increased as gestation progressed and spring calving heifers displayed increased TBF. When adjusted for BW, an additional main effect of treatment was observed (P = 0.0007) in which LOW heifers had increased TBF compared to CON heifers. There were no significant main effects of treatment or season or interactions thereof on the proportion of females cycling at the start of the breeding season (P > 0.05). Additionally, there were main effects of treatment (P = 0.0095; P = 0.02) and season (P = 0.012; P = 0.007) on calf ADG and weaning weights, respectively whereby calves born to CON females grew faster than calves born to LOW heifers, and SPRING calves gained more rapidly than FALL calves. Partial budgeting demonstrated that LOW bred heifers were $250/hd less expensive to purchase than CON heifers due to lighter BW. Calves born to LOW females yielded $6.38 less per calf compared to CON calves. The discrepancy in reproductive efficiency coupled with the failure of LOW females to achieve BW similar to CON females resulted in a difference of $403/hd in average cull value between LOW and CON females in which CON females were worth more. Thus, CON females were $159.18 more profitable than LOW females when purchased as bred heifers and sold at the weaning of their first calf. In conclusion, though uterine artery BF was not negatively affected, low input heifer development resulted in sub-optimal heifer growth, poor first calf performance, and inadequate reproductive efficiency.

Author: Shelby Lynn Rosasco
Publisher:
ISBN:
Category :
Languages : en
Pages : 232

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Two experiments were conducted to determine the influence of increased nutrient intake on beef heifer performance and reproductive efficiency. Experiment 1 evaluated the effect of heifer development supplementation regimen on heifer performance and reproduction during the pre- and post-breeding period. Heifers were developed grazing native range and supplemented to achieve 1) a constant rate of gain (CG) or 2) low rate of gain for the first half of development period followed by a high rate of gain for the remaining half of the development period (LoHi). Heifer performance was similar over the development period, with supplementation regimen having no effect on reproductive performance between treatments. Feed costs and costs to develop 1 pregnant heifer was decreased for LoHi heifer compared to CG heifers due to supplementation strategy. Following breeding heifers were stratified and randomly assigned to graze native pasture and supplemented at a low (CON) or high (High) rate for 30 d. CON heifer had a trend for increased AI pregnancy rate compared to High heifers, indicating a potential influence of nutrition on reproductive success. Accurately predicting forage nutrient composition during Exp. 1 impacted performance, altering predicted gains. In Exp. 2 heifers were individually fed a silage based diet to imitate treatments and predicted gains from Exp. 1. Heifer BW was similar among treatments over the development period. Although total ADG was similar among both treatment, ADG and intake was increased for CG heifers during the first 45 d, while LoHi heifer ADG and intake was increased over the last 45 d of the development period. Feed efficiency increased for LoHi heifers and decreased for CG heifers over the treatment period, indicating a potential compensatory gain effect. Reproductive traits measured were not impacted by development strategy; however, additional research is warranted to fully understand the impact of increased nutrient intake and compensatory gain on metabolic hormones, oocyte competence, and follicular microenvironment. In summary, these experiments provided further evidence of the impact of nutrition on reproductive performance, with future research warranted specifically investigating follicular fluid metabolic hormone concentrations and gene expression in oocytes and granulosa cells, and their impact on reproductive success.

Author: Scott A. Moore
Publisher:
ISBN:
Category : Breeding
Languages : en
Pages : 0

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Author: Mahmoud Makarechian
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 42

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Author: Lesly Ray Sprott
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 228

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