Oscar Alejandro Ojeda-Rojas
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View article: Hybrid Simulation Model For Economic-Financial Evaluation In Integrated Crop-Livestock Systems
Hybrid Simulation Model For Economic-Financial Evaluation In Integrated Crop-Livestock Systems Open
Mixed or integrated Crop-Livestock Systems (iCLS) have been in focus for the potential benefits they can provide concerning environmental, social, and economic directions, as compared with those of monoculture systems; however, iCLS practi…
View article: A Universal 6iL/E4 Culture System for Deriving and Maintaining Embryonic Stem Cells Across Mammalian Species
A Universal 6iL/E4 Culture System for Deriving and Maintaining Embryonic Stem Cells Across Mammalian Species Open
SUMMARY The derivation of authentic embryonic stem cells (ESCs) from diverse mammalian species offers valuable opportunities for advancing regenerative medicine, studying developmental biology, and enabling species conservation. Here, we r…
View article: Establishment of bovine extraembryonic endoderm stem cells enables efficient blastoid formation
Establishment of bovine extraembryonic endoderm stem cells enables efficient blastoid formation Open
Extraembryonic endoderm stem cells (XENs) resemble the primitive endoderm of blastocyst and provide valuable alternatives for understanding hypoblast development and building stem cell-based embryo models. Here, we report that a chemical c…
View article: The economic impact of purulent vaginal discharge in dairy herds within a single lactation
The economic impact of purulent vaginal discharge in dairy herds within a single lactation Open
The goal of this study was to calculate the cost of purulent vaginal discharge (PVD) in dairy cows. The dataset included 11,051 cows from 16 dairy herds located in 4 regions of the United States. Purulent vaginal discharge was characterize…
View article: A single dose of FSH or hCG during a split-time AI program did not enhance follicular growth or pregnancy per artificial insemination in beef heifers
A single dose of FSH or hCG during a split-time AI program did not enhance follicular growth or pregnancy per artificial insemination in beef heifers Open
The objective of this study was to evaluate the effect of a low dose of hCG or FSH on follicle growth and pregnancy per artificial insemination (AI) in crossbreed beef heifers subjected to a split-time AI program. All heifers (n = 386) wer…
View article: Analysis of the USDA’s 2017 Cow-Calf Management Practices Results: Part 1—Calf Crop and Calving Distribution
Analysis of the USDA’s 2017 Cow-Calf Management Practices Results: Part 1—Calf Crop and Calving Distribution Open
This publication analyzes the calf-crop and calving distribution data reported on NAHMS Beef 1997 and provides insights and practical recommendations. Written by Angela Gonella, Oscar Alejandro Ojeda-Rojas, João Bittar, and Mario Binelli, …
View article: PSVIII-11 Agent-based simulation model to evaluate the economic performance of reproductive programs in beef cattle
PSVIII-11 Agent-based simulation model to evaluate the economic performance of reproductive programs in beef cattle Open
The objective of this study was to create a stochastic, agent-based simulation model to compare the economic performance of reproductive strategies in beef cattle. The model was parameterized using data from a real herd and the scientific …
View article: PSVII-26 Follicular growth in beef cows when using a low dose of FSH and hCG at the time of CIDR removal in a 7-day co-synch + CIDR protocol
PSVII-26 Follicular growth in beef cows when using a low dose of FSH and hCG at the time of CIDR removal in a 7-day co-synch + CIDR protocol Open
The aim of the study was to compare the growth of the periovulatory follicle in crossbreed cows receiving either a low dose of hCG (150 IU; Chorulon®, Merck) or a low dose of FSH (20 mg)Folltropin®, Vetoquinol) vs. a control group when app…
View article: PSXI-1 Agent-based simulation model to evaluate the technical performance of reproductive programs in beef cattle
PSXI-1 Agent-based simulation model to evaluate the technical performance of reproductive programs in beef cattle Open
A stochastic, agent-based simulation model was created to compare the technical performance of reproductive strategies in beef cattle. The model was parameterized using field data and peer-reviewed scientific literature using AnyLogic soft…
View article: PSXII-36 Use of FSH or hCG to enhance follicular growth and pregnancy per artificial insemination during a split-AI program in crossbreed beef heifers
PSXII-36 Use of FSH or hCG to enhance follicular growth and pregnancy per artificial insemination during a split-AI program in crossbreed beef heifers Open
The objective of the study was to compare follicle growth and pregnancy per artificial insemination (P/AI) in crossbreed heifers receiving either a low dose of hCG (150 IU) or a low dose of FSH (20 mg) vs. a control group during the final …
View article: An agent-based simulation model to compare different reproductive strategies in cow-calf operations: Technical performance
An agent-based simulation model to compare different reproductive strategies in cow-calf operations: Technical performance Open
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\n The objective of this study was to create a stochastic, agent-based simulation model that allows to compare the technical and economic performance of reproductive strategies on a synthetic population of beef cattle. The model was create…
View article: The Economy of Puberty and Early Pregnancy Diagnosis in Nellore and Nellore X Angus Females
The Economy of Puberty and Early Pregnancy Diagnosis in Nellore and Nellore X Angus Females Open
Cash flows were developed to verify, over a 15-year period, the effect of anticipating puberty (using feedlot and nutritional supplementation) and pregnancy diagnosis (using conventional transrectal ultrasound or color Doppler) on the net …
View article: Economic Assessment of the Productive Parameters in Meat Sheep Production Using Discrete Event and Agent-Based Simulation
Economic Assessment of the Productive Parameters in Meat Sheep Production Using Discrete Event and Agent-Based Simulation Open
A hybrid stochastic model was developed including discrete events and agent-based simulations in order to identify the productive parameters and management criteria that most affect meat sheep production. A sheep herd on a pasture terminat…
View article: A simulation model to evaluate the economic consequences of insemination programs in dairy herds: timed artificial insemination and sex-sorted semen
A simulation model to evaluate the economic consequences of insemination programs in dairy herds: timed artificial insemination and sex-sorted semen Open
The objective of this study was to develop a simulation model to analyse the technical, economic, and financial performance of using different reproductive strategies in dairy herds. Strategies simulated were: artificial insemination (AI) …
View article: Exacerbated conceptus signaling does not favor establishment of pregnancy in beef cattle
Exacerbated conceptus signaling does not favor establishment of pregnancy in beef cattle Open
A substantial proportion of cows had EEM (31%) and LEM (20%) even after transferring multiple blastocysts. This argues that mortality was due to poor uterine receptivity that could not be reversed by supplemental P4 or overcome by transfer…
View article: Perturbations in the uterine luminal fluid composition are detrimental to pregnancy establishment in cattle
Perturbations in the uterine luminal fluid composition are detrimental to pregnancy establishment in cattle Open
Subtle perturbations imposed to the native intrauterine milieu, such as those caused by a single, low-volume collection of ULF, profoundly disturbs intrauterine composition and pregnancy success. At least 4 d were necessary for the uterus …
View article: A simulation model to evaluate the economic consequences of insemination programs in dairy herds: timed artificial insemination and sex-sorted semen
A simulation model to evaluate the economic consequences of insemination programs in dairy herds: timed artificial insemination and sex-sorted semen Open
The objective of this study was to develop a simulation model to analyse the technical, economic, and financial performance of using different reproductive strategies in dairy herds. Strategies simulated were: artificial insemination (AI) …
View article: Serum concentration of sex-steroids, endometrial expression of their receptors, and endometrial morphology during the estrous cycle in Bos taurus Criollo and crossbred cows
Serum concentration of sex-steroids, endometrial expression of their receptors, and endometrial morphology during the estrous cycle in Bos taurus Criollo and crossbred cows Open
Romosinuano (Romo) and Costeño con cuernos (CCC) are Bos taurus criollo breeds (adapted to the conditions of the tropics) that presented higher plasmatic Progesterone (P4) concentration during the luteal phase compared to non-adapted genot…
View article: Modelo de simulação para análise econômica do uso de biotecnologias reprodutivas em rebanhos leiteiros
Modelo de simulação para análise econômica do uso de biotecnologias reprodutivas em rebanhos leiteiros Open
\n As biotecnologias reprodutivas têm uma importante relação com os resultados econômicos dos rebanhos leiteiros. Sua adoção implica o investimento de quantidades conhecidas de recursos, porém, há uma clara dificuldade por parte de produto…