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Accurately measuring body weight (BW) is of great importance for cow-calf producers in the United States, which can lead to better marketing and nutrient management decisions. Traditionally, BW has been recorded using a walk-over scale or approximated by visual observation. Recently, technology has come out that allows BW prediction using three-dimensional (3D) images. The objective of this study was to determine the efficacy of 3D imaging technology as a method to predict BW of beef heifers. Dorsal 3D images were collected on 69 Red Angus/Simmental yearling heifers. Heifers were approximately 12 mo of age that ranged from 282.1 to 440.0 kg of BW. For image collection, a depth camera (Kinect Azure, Microsoft) was placed above the animals, approximately 3 to 4 meters above the floor surface within the alley of a working facility. The image collection software was written in Python (version 3.8) programming language. For a high-quality image to be recorded, heifers needed to be handled in small groups and kept separate. Heifers also needed to have all four feet on the ground and no interference from other animals in the image. Corresponding scale-measured BW were also recorded for each animal concurrent with depth images collection. Heifers were limit fed and weighed in the morning before feeding for both scale measured BW and image collection. The depth images were analyzed using a customized program written in MATLAB (R2022a). Heifer dorsal projected volume was estimated by adding height pixel values that formed the heifer's dorsal area, excluding the head region. Body weights were regressed from projected heifer body volumes extracted from the depth images, and then metabolic BW (MBW) was calculated using the 0.75 power adjustment of BW. Performance of the prediction model was analyzed using the coefficient of determination (R2) obtained from the regression of projected volume and actual scale BW and the standard error of the mean (SEM) of the predicted BW. Data were analyzed using the PROC REG and PROC CORR procedures in SAS (v9.4). Prediction of BW using image-extracted dorsal projected volume produced an R 2 = 0.89 and SEM = 3.3 kg. When analyzing the correlation of volume to BW, the Pearson correlation coefficient of r = 0.94 (P < 0.0001) was obtained. Regression of projected volume to MBW produced an R 2 = 0.89 and SEM = 0.57 kg. Results show that this model demonstrates the ability to accurately predict BW using depth images projected dorsal volumes on yearling heifers. These results illustrate that 3D images can be used to accurately measure BW of growing heifers that may enhance the ability of cow-calf producers to pro-actively manage grazing livestock. [ABSTRACT FROM AUTHOR]

Current trends in the beef industry focus on selecting production traits with the purpose of maximizing calf weaning weight; however, such traits may ultimately decrease overall post-weaning productivity. Therefore, the objective of this study was to evaluate the effects of actual milk yield in mature beef cows on their offspring’s dry matter intake (DMI), BW, average daily gain, feed conversion ratio (FCR) and residual feed intake (RFI) during a ~75-day backgrounding feeding trial. A period of 24-h milk production was measured with a modified weigh-suckle-weigh technique using a milking machine. After milking, cows were retrospectively classified as one of three milk yield groups: Lower (6.57±1.21 kg), Moderate (9.02±0.60 kg) or Higher (11.97±1.46 kg). Calves from Moderate and Higher milk yielding dams had greater (P<0.01) BW from day 0 until day 75 at the end of the backgrounding feeding phase; however, day 75 BW were not different (P=0.36) between Lower and Moderate calves. Body weight gain was greater (P=0.05) for Lower and Moderate calves from the day 0 BW to day 35 BW compared with Higher calves. Overall DMI was lower (P=0.03) in offspring from Lower and Moderate cows compared with their Higher milking counterparts. With the decreased DMI, FCR was lower (P=0.03) from day 0 to day 35 in calves from Lower and Moderate milk yielding dams. In addition, overall FCR was lower (P=0.02) in calves from Lower and Moderate milk yielding dams compared with calves from Higher milk yielding dams. However, calving of Lower milk yielding dams had an increased (P=0.04) efficiency from a negative RFI value compared with calves from Moderate and Higher milking dams. Results from this study suggest that increased milk production in beef cows decreases feed efficiency during a 75-day post-weaning, backgrounding period of progeny. [ABSTRACT FROM PUBLISHER]

The objective was to determine the effect of stockpiled forage type and protein supplementation on VFA production, serum metabolites, and heifer BW. Over 2 yr, spring-born, crossbred heifers (n = 45) were stratified by BW at weaning and randomly assigned to 1 of 3 forage treatments: 1) endophyte-infected tall fescue (TF; Festuca arundinacea), 2) big bluestem (Andropogon gerardi Vitman) and indiangrass (Sorghastrum nutans L.) combination (BI), or 3) switchgrass (SG; Panicum virgatum L.). Forage treatments were then randomly assigned to receive 1 of 2 supplement types: 1) 0.68 kg·heifer-1·d-1 of dried distiller's grains with solubles (DDGS; 28% CP, 74% RUP, and 88% TDN) or 2) 0.22 kg·heifer-1·d-1 of blood meal and fish meal (BF; 72.5% CP, 67.5% RUP, and 69.5% TDN), resulting in a 3 × 2 factorial arrangement of treatments. Treatments were initiated every year in January and terminated in April at the onset of a 60-d breeding season. Body weights and serum samples were collected approximately every 28 d from initiation of grazing until breeding. Serum glucose concentrations were greater (P = 0.05) for heifers grazing SG. Circulating NEFA concentrations were greater (P = 0.04) in TF heifers. Serum urea N (SUN) was not influenced (P = 0.37) by forage type. Ruminal acetate concentration and acetate:propionate ratio were greater (P = 0.04) in heifers grazing SG pastures. Heifer BW change from January to February and overall BW change were greater (P < 0.01) for TF heifers. However, BW change from March to April was not different (P = 0.84) among forage types. Serum glucose and SUN concentrations exhibited (P < 0.05) supplement type × sampling time interactions. Ruminal acetate tended to be greater (P = 0.09) and butyrate concentrations were greater (P < 0.01) for BF-supplemented heifers. The acetate:propionate ratio was not influenced (P = 0.15) by supplement type. Supplement type did not influence (P > 0.13) BW or BW change from January to February and January to April; however, heifers fed DDGS gained (P = 0.03) more BW from March to April. Heifer BW change from February to March exhibited (P < 0.05) a forage type × supplement interaction with BF heifers gaining more BW on BI pastures than DDGS heifers. Overall, developing heifers on low-quality native forages initially delayed BW gain; however, heifers seemed to quickly adapt to the lower-quality forage, resulting in similar BW gains in March and April. [ABSTRACT FROM AUTHOR]

Negative energy balance (NEB) and metabolic dysfunctions have been shown to impair reproduction; however, the mechanisms and molecular pathways that couple energy status to reproductive function are poorly defined. Previous studies have indicated an association between elevated beta-hydroxybutyrate (BHB) and reproduction efficiency. To identify molecular pathways that couple metabolic dysfunctions to reproduction, 10 wethers were randomly assigned to be centrally injected into the lateral ventricle through intracerebroventricular cannulas with 1 mL of β-hydroxybutyric acid sodium salt solution (BHB; 12,800 μmol/L) or saline solution (0.9% NaCl). Two hours after injection, wethers were humanely euthanized and the hypothalamus and pituitary were harvested for transcriptome characterization using RNA sequencing. Ribonucleic acid was extracted from the hypothalamus and pituitary and deeply sequenced (468,912,732 reads from the hypothalamus and 515,106,092 reads from the pituitary) using an Illumina Hi-Seq platform and aligned to the Bos taurus and Ovis aries genomes using BLAST. Of the total raw reads, 87% (hypothalamus) and 90.5% (pituitary) mapped to the reference Ovis aries genome. Within these 2 sets of reads, approximately 56% in the hypothalamus and 69% in the pituitary mapped to either known or putative genes. Fragments per kilobase of transcripts per million normalized counts were averaged and ranked to identify the transcript expression level. Gene Ontology analysis of these 2 gene sets (using DAVID Bioinformatics Resources) identified biological process functions related to genes shared between tissues as well as functional categories with tissue-specific enrichment. Injection of BHB altered (P < 0.05) expression of 11 genes in the pituitary and 44 genes in the hypothalamus. Three genes (zinc finger and BTB domain containing 16 [ZBTB16], FK506 binding protein 5 [FKBP5], and eukaryotic elongation factor 2 kinase [EEF2K]) were influenced (P < 0.05) by BHB injection in both tissues. Of these 3 genes, FKBP5 is of particular interest as a mediator of fertility during NEB, due to its role in modulating stress at the hypothalamus-pituitary-adrenal axis. Functional enrichment analyses revealed that BHB injection altered expression of genes in pathways related to stimulus perception, inflammation, and cell cycle control. The set of genes altered by BHB creates a foundation from which to identify the signaling pathways that suppress fertility during NEB or periods of metabolic dysfunctions. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of reducing dietary rumen-degradable protein (RDP) and rumen-undegradable protein (RUP) on protein and energy metabolism in heat-stressed dairy cows. Eighteen primiparous and 30 multiparous mid-lactation Holstein cows were used in a completely randomized design arranged in a 2 × 2 factorial (n = 12/treatment). Cows were randomly assigned to 1 of 4 dietary treatments that included 2 levels of RDP (10 and 8%; D) and 2 levels of RUP (8 and 6%; U) of dry matter for 21 d as (1) 10D:8U, (2) 8D:8U, (3) 10D:6U, and (4) 8D:6U. Diets were isoenergetic and contained 50% forage and 50% concentrate (dry matter basis). Cows were housed in a freestall barn. Three weeks before start of treatments, all animals were fed the 10D:8U diet and received supplemental cooling to prevent heat stress. During the treatment period, cows experienced a daily increment in temperature-humidity index from 74 to 82 for 1000 to 2000 h. Blood samples were collected on d -1 and 21 of the treatment period to determine plasma concentrations of AA, glucose, insulin, fatty acids, and β-hydroxybutyrate. For primiparous cows, reducing from 10 to 8% RDP decreased insulin concentrations. For multiparous cows, we found significant RDP by RUP interactions for insulin, β-hydroxybutyrate, fatty acids, total essential AA, and 3-methylhistidine concentrations. Reducing from 10 to 8% RDP decreased insulin concentrations at 6% RUP, but concentrations did not change when reducing RDP at 8% RUP. Reducing from 10 to 8% RDP decreased β-hydroxybutyrate concentrations at 8% RUP, but concentrations did not change when reducing RDP at 6% RUP. Reducing from 10 to 8% RDP increased nonesterified fatty acid and total essential AA concentrations at 8% RUP, but concentrations did not change when reducing RDP at 6% RUP. Reducing from 8 to 6% RUP decreased 3-methylhistidine concentration at 8% RDP, but not at 10% RDP. Reducing from 8 to 6% RUP increased milk protein yield efficiency in primiparous and multiparous cows. These results indicate that reducing RDP and RUP lowers circulating insulin, which was associated with mobilization and utilization of fatty acids. Reduced RDP and RUP increases the use of AA to maintain milk protein synthesis and limit AA catabolism in cows exposed to warm climates., (Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)