Walking Distance and Performance of Drylot Developed Beef Heifers Following Being Moved to a Grazing Situation

Research has shown that heifers moved from a drylot to grass after AI have decreased weight gains and pregnancy success compared to heifers developed on range. This effect could potentially be due to inexperience in a specific grazing environment, which could result in greater time spent exploring a new environment. In this study beef heifers were moved from a drylot to spring grass at two different times and their activity compared. Heifers in a drylot walked less than heifers grazing spring forage. However, following being moved to spring forage heifers that had been adjusted to grass for about a month took fewer steps during their first four days of grazing then did the heifers that did not have previous grazing experience. Heifers without prior grazing experience also lost weight during this period. In summary, moving drylot developed heifers to spring forage affected performance and activity

Uterine Environment and Pregnancy Rate of Heiferswith High Blood Urea Concentrations

Reports demonstrate that excess dietary protein significantly alters the ionic composition of uterine fluid during the luteal phase ultimately decreasing fertility. Since the early bovine embryo cannot adapt to changes in the uterine environment, changes in the concentrations of ions (pH) in the uterus can be unfavorable to embryo development and survival therefore having negative effects on fertility. In this study, heifers fed a high protein diet had elevated systemic concentrations of plasma urea nitrogen (PUN) compared to heifers fed a control diet. However, there was no deleterious effect on uterine pH or reproductive success. In summary, excess protein in a diet did increase PUNs to a concentration that has previously been reported to be detrimental to pregnancy success; however, there was no negative effect on uterine pH or pregnancy success

Post-weaning Nutritional Programming of Ovarian Developmentin Beef Heifers

The nutritional management of replacement females from weaning to breeding is critical to lifetime productivity. Traditionally, cereal grains have been used to develop replacement heifers to attain puberty and enter the breeding system at a younger age. However, overfeeding heifers decreases number of calves weaned, while peri-pubertal caloric restriction increased primordial follicle numbers in the developing ovary. The number of primordial follicles a female has can determine her overall fertility; females with a greater amount of follicles have greater reproductive lifespans. In this study, two groups of heifers were developed to prebreeding status. One group received a control diet (228 kcal ME/BW kg0.75) while the other received a restricted diet (157 kcal ME/BW kg0.75) for 84 days, and were then stepped up to receive a diet containing 277 kcal ME/BW kg0.75. Both groups were evaluated at three different time points for number of primordial follicles. Heifers on the restricted diet had more primordial follicles than control heifers at 13 mo of age. In summary, heifer input costs could be decreased without negatively effecting overall fertility and perhaps improve fertility

iTRAQ-Based proteomic dataset for bovine pre-ovulatory plasma and follicular fluid containing high and low Estradiol

This is isobaric tags for a relative and absolute quantification (iTRAQ)-Based Proteomic Data on bovine plasma (PL) and follicular fluid (FF) containing high and low pre-ovulatory circulating concentration of estradiol (E2). The PL and FF were collected from nine beef cows that were identified to initiate a new follicular wave on day -4 during synchronization. Follicular dynamics and ovulatory response were monitored using transrectal ultrasonography. Blood samples were collected at slaughter and FF was aspirated from dominant follicles (DF; >10 mm). Estradiol concentrations in PL and FF were measured by radioimmunoassays. Plasma and FF were labeled as containing high E2 (PL HE2 and FF HE2) or low E2 (PL LE2 and FF LE2). Abundant proteins (albumin, IgG, IgA, and alpha-1-antitrypsin) were depleted from the four PL and FF samples. Peptides were labeled with iTRAQ reagents and analyzed using 2-dimentional liquid chromatography ESI-based mass spectrometry. Proteins were identified and quantified using SEQUESTTM search engine embedded in Proteome Discoverer. The proteins matched with at least one unique peptide at minimum 95% confidence were considered positive identifications. Protein expression levels were determined by assigned fold change of >2.0 or <0.5 between any pair from the four sample types. The paired comparisons made were PL HE2 and PL LE2, FF HE2 and FF LE2, PL HE2 and FF HE2, and PL LE2 and FF LE2. Protein Analysis Through Evolutionary Relationships (PANTHER) and Database for Annotation, Visualization and Integrated Discovery (DAVID) were used to classify protein functions. This dataset includes the overview of workflow for identification and quantification of proteins and details on 231 proteins identified which includes 103 up- and down-regulate proteins. This dataset can be useful for further probing of the identified regulated proteins to better understand folliculogenesis and ovulation, particularly in bovine. This dataset is related to the article ‘iTRAQ-Based Proteomic Analysis of Bovine Pre-ovulatory Plasma and Follicular Fluid’ by P. A. Afedi, E. L. Larimore, R. A. Cushman, D. Raynie, G. A. Perry. Domestic Animal Endocrinology. https://doi.org/10.1016/j.domaniend.2021.10660