Animal Sciences Doctoral Work

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Ancestral Breed Grouping for Improving Animal Modeling in Admixed Populations and Its Use in Leptin (Genetic and Hormone) Association Studies with Performance Traits in Commercial Beef Cow Herd
(North Dakota State University, 2021) Bhowmik, Nayan
The first study investigated American Aberdeen (AD) cattle's genetic structure and its genetic relationships with five American taurine beef breeds and the genetic population structure of a related admixed cattle herd for improved statistical modeling. The last two studies investigated the role of leptin (LEP) c.73C>T polymorphism, leptin diplotype (LEPD), and leptin hormone (LEPH) concentration on reproductive, growth, size, feeding, and carcass ultrasound traits in beef cows and heifers. High levels of polymorphism were observed in admixed, Red Angus, and Gelbvieh (GV) populations. The lowest level of polymorphism was found in AD followed by undetermined parentage. Pairwise fixation index displayed the largest genetic differentiation between AD and GV, Simmental, and Shorthorn breeds. Even though founder animals originated from the Angus breed, the AD breed exhibited unique genomic characteristics. Mixed animal models with or without pedigree that included the primary ancestral breed group (ABG) for admixed individuals developed from diversity analyses performed better than models without the ABG. With these improved models, novel relationships between LEP genotype and number of follicles and ovary size were identified. Similar relationships of the LEP genotype in multiple growth and weight traits that have been published before have been confirmed. However, reverse relationships were observed for feed efficiency. The LEPD showed associations for feed efficiency, weight traits, and body size traits. Novel relationships between LEPH categories (high vs. low) were reported on two feeding behavior traits, including number of meals per day and feed intake per meal. However, no relationship was observed between LEP genotype and plasma LEPH concentration in this population. Literature indicates the increased productivity of the T allele for growth and carcass attributes, so it was expected that the same increased productivity would be found for reproductive traits. Therefore, the T allele of LEP c.73C>T marker could be used as a valuable marker for selecting for improved growth, body size, and reproductive performance in commercial beef heifers. Also, circulatory LEPH before the breeding season may serve as a predictor for feeding behavior, body size, and reproductive traits. Even so, not all comparisons could be statistically proven; therefore, additional investigations may be warranted.
Computer Vision System as a Tool to Estimate Pork Marbling
(North Dakota State University, 2017) Liu, Jeng-Hung
Currently pork marbling is assessed subjectively in the industry, because of the limited methods and tools that are suitable for the industry. In this dissertation, we are devoted to develop a computer vision system for objective measurement of pork which suits the industrial needs. Experiment 1 examined the possibility of using computer vision system (CVS) to predict marbling in a lab-based experiment using pork samples that were already trimmed of subcutaneous fat and connective tissue. Experiment 2 an industrial scale CVS was built to predict the 3rd and 10th rib pork chop’s marbling. Experiment 3 the industrial scale CVS was tested in the meat plant and images of whole boneless pork loin were collected. The CVS predicted marbling were compared with subjective marbling score using crude fat percentage (CF%) as standard. In experiment 1 subjective marbling score had a correlation of 0.81 with CF% while CVS had a 0.66 correlation. CVS has shown an accuracy of 63% for stepwise regression model and 75% for support vector machine model. These results indicate that CVS has the potential to be used as an tool to predict pork intramuscular fat (IMF)%. In experiment 2 the accuracy of CVS predicting pork chop CF% was 68.6% and subjective marbling was 70.1%. A drop of accuracy in predicting anterior chop CF% for both CVS and objective marbling score was observed when compared to posterior chop, this suggest that there is a discrepancy in accuracy between the anatomy location of samples collected. In experiment 3 the accuracy of CVS predicting boneless whole loin was 58.6% and subjective marbling score was 53.3%. In this research, CVS has demonstrated a consistency of accuracies using different pork samples. CVS has shown higher accuracy when predicting whole boneless loin IMF% when compared to subjective assessment.
The Effects of Maternal Diet on Passive Transfer of Immunity to the Neonatal Beef Calf, and Calf Immune Response to Vaccination and Immunostimulants
(North Dakota State University, 2018) Gaspers, James Joseph
To investigate the effects of maternal diet on passive transfer of immunity to the neonatal beef calf, and calf immune response to vaccination and immunostimulants, three experiments (Exp.) were completed. Results from Exp. 1 indicated that there was no effect of supplemental starch to cows on colostrum production, offspring birth weight, incidence of dystocia, respiratory acidosis, and the passive transfer of immunity. Results from Exp. 2 indicated that both the needle – free injection devices (NFs) and needle and syringe (NS) initiate a haptoglobin (Hp) inflammatory response (P < 0.001). After injection bovine viral diarrhea virus (BVDV) type 2 antibody titers continually declined from d 0, 7, 28, and 115 across both NS and NF treatment groups (P < 0.001). After secondary booster vaccination on d 115, BVDV type 2 antibody titers significantly increased by d 143 (P < 0.001). The use of NFs will maintain a level of immunity that has been seen by the use of conventional NS vaccine administration methods. In Exp. 3, treatments containing a modified live vaccine (MLV) antigen initiated an Hp inflammatory response over time (P < 0.001). Interferon gamma was not significantly different across treatment over time (P = 0.39); however, there was a threefold increase in treatment three over time. Treatments containing a MLV BVDV antigen maintained BVDV type 2 antibodies over time (P <0.001). Feed intake and feeding behavior were unaffected by the use of the vaccine and/or immunostimulant.
Effects of Maternal Nutrition During Gestation on Viscera Energy Use in Ruminant Dams and Offspring and Hypothalamic Neurohormone Content in the Offspring
(North Dakota State University, 2015) Prezotto, Ligia Dias
The extensive use of grazing systems for ruminant livestock and the high variation in forage quality throughout the year have important impacts on production. Changes in feed quality and availability cause alteration in the nutritional and physiological status of gestating animals. Modifications of the maternal nutritional environment throughout fetal development can have an impact on later performance of the offspring. Adjustments in maternal metabolism have been correlated with an increase in maternal energy use during pregnancy, and also further adjustments that occur in the dam’s metabolism to provide adequate oxygen (O2), nutrients, and energy for fetal growth and maternal maintenance systems. Moreover, energy utilized by fetal visceral tissues can be altered in response to changes in maternal feed intake. Prolonged changes in maternal feed intake during early pregnancy, the time which fetal brain development is taking place, can result in up- and/or down-regulation of neurohormones which play an important role in controlling long-term energy utilization and feed intake in the offspring. We designed three different studies with the main objective to investigate how maternal nutrient restriction throughout gestation or during different periods of gestation affects visceral organ metabolism in the dam and in the fetus. Furthermore, we aimed to understand the effects of fetal growth restriction on postnatal liver and small intestine mass, energy use, and content of hypothalamic neurohormones that control feed intake and energy metabolism. Our results indicate that, maternal hepatic and jejunal mass and energy use are impacted by nutrient restriction and strategic realimentation during different stages of gestation. Similar responses are also observed in fetal visceral development, metabolism and liver energy use in postnatal life. Moreover, arginine supplementation appears to be a nutritional strategy that diminishes the possible deleterious effects in maternal and fetal visceral metabolism in response to nutrient restriction. iv Finally, maternal nutrient restriction throughout gestation decreased the number of cells expressing proopiomelanocortin (POMC) protein in the offspring hypothalamus, perhaps influencing energy metabolism in the offspring.
Effects of Nutrient Restriction, Realimentation, and Twinning on Plasma Volume, Umbilical Hemodynamics and Placental Characteristics in the Pregnant Adolescent Ewe
(North Dakota State University, 2019) Vasquez Hidalgo, Manuel Alexander
Reproductive physiology in production animals is a key economic component of longevity and profitability of animal farming. There are several components that can benefit or compromise adequate pregnancy periods. Sheep production is not only a very important economic activity for farmers around the United States, but sheep are also an important medical and surgical model to study human diseases. Our findings suggest that estradiol-17 beta could be involved in acute increased plasma volume early in gestation which can benefit overall gestation. We report that umbilical blood flow decreases upon nutrient restriction in adolescent ewes and does not recover upon realimentation. Finally, we suggest that a similar umbilical blood flow, placental development and plasma volume expansion in twins and singleton pregnancies could be enough to obtain similar birthweights in singletons and twins.
The Effects of Red Meat or Sugar Supplementation during Gestation and Lactation on Maternal Reproduction, Maternal and Offspring Blood Parameters, and Offspring Body Composition
(North Dakota State University, 2019) Siomka, Alexis Michelle
Using swine as a model for humans, this study was conducted to examine whether maternal consumption of added protein (red meat) or free sugar (glucose) throughout gestation and lactation was associated with maternal reproduction, maternal and offspring blood parameters, and offspring mature body composition. Maternal breed of sows of at least one year of age at breeding were utilized. At D-40 of gestation, sows were randomly assigned to one of four dietary supplementation treatments 1) Control (CON): corn-soy gestation diet; 2) Beef (GB): 4 oz cooked beef patty; 3) Sugar (SUG): sugar on a caloric equivalent to the beef patty; 4) Half sugar and half beef (SB): a supplementation of a beef and sugar mixture. Fewest piglets farrowed per litter was seen in the CON sows when compared to GB, SUG or SB treatments (P<0.04), with no difference in total number farrowed between GB, SUG, and SB sows (P>0.6). Although GB sows had piglets with a lower average birth weight than CON sows (P=0.02) and no difference in average piglet growth during lactation (P=0.17) or in weaning weight (P=0.08). There were no (P>0.05) differences in traits measured in the sow (subcutaneous backfat depth, body weight, and energy balance). No treatment effect was seen in low-density lipoprotein (LDLch) (P=0.31); however, serum LDLch continued to decrease for SUG sows from early to late gestation. There were differences for high-density-lipoproteins (HDLch) with GB sows having the greatest HDLch levels when compared to CON and SUG during mid gestation (P=0.05 and 0.004, respectively). There were treatment differences seen during mid- and late gestation with GB sows having higher total cholesterol (TOTch) than SUG and CON sows (P<0.05). During mid gestation, TOTch was higher for GB than SB (P=0.006), resulting in lower TOTch for SB during late gestation (P=0.08). It can be concluded that the supplement provided during gestation and lactation, had a minimal effect on overall maternal reproduction, maternal and offspring blood parameters, and on mature body composition of offspring. Positive outcomes for offspring and mothers cannot be expected if the supplementation is not needed.
Effects of Replacing Supplemental Sucrose with Beef During Mid to Late Gestation on Maternal Health and Fetal Growth and Development Using a Sow Biomedical Model
(North Dakota State University, 2019) Nelson, Megan Alice
Americans consume three percent more total daily calories from sugar than current recommendations. Maternal diets high in sugar can cause obesity and diabetes mellitus. Objectives were to compare supplemental dietary sucrose to a protein alternative on maternal health and fetal programming utilizing a sow biomedical model. Pregnant sows (Landrace × Yorkshire, average BW = 222 ± 35 kg, n = 21) were fed a corn-soybean meal-based diet (CSM) at one percent BW at 0700 h daily from d 29 (± 1.47) to 111 (± 0.58) of gestation. Sows were randomly assigned to dietary supplement treatments: 126 g CSM (CON, n = 5), 110 g cooked ground beef (BEEF, n = 6), 85.5 g sucrose (SUCR, n = 5), or the combination of 54.8 g BEEF and 42.7 g SUCR (B+S, n = 5). Dietary supplements were fed three times daily from d 40 to 110 (± 0.58) of gestation. A repeated measures design was modeled using the MIXED procedure of SAS. Dietary treatment did not influence gestational BW (P ≥ 0.99), subcutaneous fat depth (P ≥ 0.09), blood chemistry panel (P ≥ 0.21), or total-, HDL-, or LDL-cholesterol, triglyceride, insulin, or C-reactive protein serum concentrations (P ≥ 0.07). Dietary treatment did not influence sow organ or lean tissue weight (P ≥ 0.42). Compared to CON, BEEF fetuses had increased BW (P = 0.01), crown to rump length (P = 0.01), nose to crown length (P < 0.01), heart girth (P = 0.02), and abdominal girth (P = 0.05). Dietary treatment did not influence fetal growth characteristics of median weight male and female fetuses (P ≥ 0.23). Compared to BEEF, SUCR fetuses had heavier liver weights (P = 0.04). Dietary treatment by sex interaction occurred for fetal kidney weight with BEEF males having heavier kidney weights compared BEEF females (P = 0.03). Dietary treatment did not influence other fetal organ or lean tissue weights (P ≥ 0.09). These results suggest beef or sucrose supplementation at 1.49 or 1.16 grams per kilogram BW per day, respectively, from day 40 to 110 of gestation had minimal impact on maternal health and fetal development.
The Effects of the Nitric Oxide (NO) System and Nutritional Plane on Ovarian Function
(North Dakota State University, 2015) Bass, Casie Shantel
Researchers predict a world population of approximately 9.5 billion people by the year 2050. Current resources, including the amount of meat that is produced, would not be able to sustain that population. Therefore, the current dissertation research was completed to assist in improving reproductive efficiency. A third of pregnancies are “lost”, or spontaneously aborted with unknown reason(s). Therefore, research has been directed towards improving reproductive efficiency, especially in regards to proper ovarian function in both pregnant and non-pregnant females. Numerous factors influence reproduction including hormones, growth and angiogenic factors, nutritional plane, and supplements such as arginine (Arg), a semi-essential amino acid and precursor for proteins, polyamines, and nitric oxide (NO). Nitric oxide is a reactive gas molecule made naturally in the body and is critical for angiogenesis, which is the development of blood vessels, generally capillaries, from pre-existing blood vessels to allow for blood flow to specific tissues. During a female’s reproductive cycle, certain reproductive tissues undergo rapid changes including vascular development and regression, and tissue growth and regression. One of those tissues, the corpus luteum (CL), is critical for pregnancy as the tissue produces progesterone (P4), a pregnancy maintenance hormone. Therefore, the objective of this research was to investigate how manipulation of the NO system via Arg supplementation to nutritionally compromised ewes impacts ovarian function and endocrine activity in non-pregnant sheep.
Energy and Mineral Supplementation Strategies for Beef Cattle Grazing the Northern Great Plains
(North Dakota State University, 2019) McCarthy, Kacie Lynn
Four experiments were conducted to evaluate different technologies and supplementation strategies that may impact beef cattle production in the Northern Great Plains. Our overarching hypothesis was that we can enhance beef cattle performance and production through strategic supplementation of energy and minerals. In experiment 1, steers were fitted with transmission beacons on collars to determine effects of preweaning creep feeder attendance influences on post-weaning performance, feeding behavior, and carcass characteristics. Calves that visited creep feeders more frequently spent more time eating and ate more meals during the first 28 d of the finishing period. In experiment 2, we utilized electronic feeders to monitor mineral intake of cow-calf pairs and found that HIGH (>90 g/d; average 125.4 g/d) intake cows and calves spent more time at the mineral feeder than their LOW (<90 g/d; average 33.5 g/d) intake counterparts. Furthermore, we noted greater concentrations of Se, Cu, and Co in livers of HIGH intake cows compared to LOW intake cows. In experiment 3, we evaluated a slow-release vitamin and mineral bolus in feedlot heifers which failed to influence heifer performance, liver mineral concentrations or carcass characteristics. Overall, heifers performed as expected while on a finishing diet from feeds sourced in the Northern Great Plains. In experiment 4, we further utilized the SmartFeed system to control intake of individual heifers assigned to different treatments in a group pasture scenario. Our results clearly show that the feed controlling portion can be used for precision feeding of individuals in extensive group managed scenarios. Though heifers had similar BW and ADG among treatment groups, treatments that provided supplemental mineral enhanced liver concentrations of Se, Fe, Cu, and Co. Furthermore, the CowManager system was able to detect divergence in highly active behavior among treatment groups, but also reported many false health and estrus-related alerts. Overall, we were able to successfully monitor individual mineral intakes in cow-calf pairs and report differences in energy and mineral supplement intakes in heifers grazing native range. We were also able to corroborate differences in supplement intakes with changes in concentrations of mineral in the liver of animals.
An Evaluation of Feeding Hempseed Cake in Finishing Cattle Diets
(North Dakota State University, 2022) Winders, Thomas
Understanding the potential of hempseed cake to be used as a livestock feedstuff is important for both industrial hemp and beef producers. Experiment 1 evaluated the effects of hempseed cake (HEMP) on growth performance, feeding behavior, plasma metabolite concentrations across time, and carcass characteristics when fed in finishing diets to heifers in comparison to dried corn distillers grains plus solubles (DDGS). Experiment 2 investigated the effects of HEMP on diet ruminal fermentation parameters, total tract digestibility, nutrient flow, and nitrogen balance in finishing steers in comparison to DDGS and a control (CON) diet containing no byproduct. Experiment 3 explored the effects of hempseed cake on immune parameters in response to an endotoxin (lipopolysaccharide) challenge in finishing steers in comparison to DDGS and CON. In experiment 1, the HEMP diet reduced heifer growth performance and hot carcass weight while not influencing dry matter intake, feeding behavior, or other carcass characteristics. Plasma urea nitrogen (PUN) was greater for heifers fed the HEMP diet, and glucose and total amino acid concentrations were not influence by treatment. In experiment 2, ruminal ammonia and total VFA concentrations were greatest for steers fed the HEMP diet. Furthermore, organic matter (OM) intake tended to be greater, OM total tract apparent digestibility was reduced, and N digestibility was greatest for steers fed the HEMP diet, and site of digestion was influenced by treatment. Nitrogen retention was greatest in steers fed the HEMP diet, suggesting treatment influence on N metabolism. In experiment 3, there was a treatment by hour interaction for PUN, and plasma glucose and NEFA were not influenced by treatment. Plasma IL-1α, IL-36RA, and TNF-α were lowest in steers fed the HEMP diet, and all other cytokines and total amino acid plasma concentrations were not influenced by treatment. Hempseed cake negatively influences growth performance in large part because of reduced total tract apparent OM digestibility, while N total tract apparent digestibility and N retention are improved and immune response is influenced, so further understanding of these outcomes is needed to explore implications of feeding hempseed cake to finishing cattle.
Genetic Markers, Cattle Disposition, and Stress Relative to Variations in Beef Tenderness
(North Dakota State University, 2012) Magolski, James David
The objective of this research was to evaluate the efficacy of genetic markers, disposition, and animal stress on variations in beef tenderness. Warner-Bratzler shear force (WBSF) values on 570 mixed breed heifers and steers were used to determine estimates of genetic selection. Cattle used for this analysis were marketed from 2008 to 2011, and included five different feedlot based research projects at the Carrington Research Extension Center (Carrington, ND). Tissue samples were collected for IGENITY® (Merial Limited, Duluth, GA) analysis. Results included both selection indices and molecular breeding values for hot carcass weight, ribeye area, yield grade, fat thickness, percent choice, marbling, tenderness, docility, heifer pregnancy rate, maternal calving ease, and stayability. These genetic based parameters were compared with actual carcass values and measurements of temperament including exit velocity, chute score, and capture score. Genetic marker assisted selection may offer a more effective means of improving cattle management strategies and product quality; however there is progress to be made on the accuracy of such predictions. In the second project, the effect of temperament and slaughter method on Minolta color scores and tenderness was evaluated. Measurements of temperament were obtained prior to slaughter on Angus x Peidmontese crossbred heifers. Heifers were slaughtered on two consecutive Mondays using either Kosher or captive-bolt slaughter methods. At approximately 24 h post-mortem, carcass measurements and marbling scores were obtained. Longissimus thoracis (LT) samples were collected and aged 14 d prior to Minolta color score and WBSF measurements. Chute score, capture score, and vocalization scores significantly correlated (P < 0.03) with blood lactate concentration. The LT from Kosher slaughtered heifers had significantly higher (P < 0.01) L*, a*, b* and WBSF values than that of captive bolt stunned heifers. The LT from captive bolt stunned heifers had significantly higher (P = 0.04) marbling, and a tendency (P = 0.08) for increased cook loss compared with that from Kosher slaughtered heifers. These data indicate that chute behavior is significantly correlated to measurements of blood lactate and suggests that the Kosher slaughter method may negatively affect meat quality parameters compared with the captive-bolt stunning method.
Genetic Predictions Using Subjective Methods of Beef Cattle Temperament Evaluation, Genetic Association Between Beef Cattle Temperament and Production Traits, and Influence of Sire and Dam Temperament on Calf Performance
(North Dakota State University, 2021) Celestino, Elfren
Beef cattle temperament is not only important to handler safety and animal welfare but also found to be related to productivity and thereby, considered an economically important trait. Constraints to improve cattle temperament are due to the inherent complexity of this trait and difficulty in measurement. Our findings suggest that traditional subjective methods (DS; docility score and TS; temperament score) of beef cattle temperament evaluation has less effect in genetic merit predictions (heritability estimates and estimated breeding value ranking) provided that evaluator is included in the model. Our novel movement-based objective method (four-platform standing scale, FPSS) using standard deviation of FPSS data (SSD) and coefficient of variation of SSD (CVSSD) can be use in place of DS and TS, but more appropriately with TS which had higher association based on genetic correlation analysis. Calf temperament had significant effect on adjusted birth weight (ABW), adjusted 205 weaning weight (205-d WW), weaning average daily gain (ADG), and weight gain (WG) where there is an increased ABW, 205-d WW, ADG, and WG with calmer temperament calves. Based on genetic correlation, ABW, 205-d WW, ADG, and WG may not be associated with calf temperament due to low correlations to majority of our models. Lastly, we found significant association between dam temperament and calf 205-d WW, ADG, and WG where dam with calmer temperament had increased calf 205-d WW, ADG, and WG.
The Impact of Age and Level of Nutrient Consumption on Pancreatic Insulin Production in Ruminants
(North Dakota State University, 2016) Keomanivong, Faithe
Video summarizing Ph.D. dissertation for a non-specialist audience.
The Impact of Digestive Enzymes in the Ruminant Animal
(North Dakota State University, 2016) Keomanivong, Faithe Elizabeth
Understanding the enzymatic activity in ruminant digestive systems is essential for securing adequate growth, reproduction and overall metabolism. In order to evaluate the impact of various nutritional sources and dietary strategies on enzymatic activity, five experiments were designed. Experiment 1 examined the influence of nutrient restriction and melatonin supplementation on maternal and fetal pancreatic development. Experiment 2 explored various phases of the reproductive cycle and the impact of intravenous arginine infusion amid differing levels of feed intake. Experiment 3 determined the effectiveness of realimentation during advancing stages of gestation. Experiments 4 and 5 examined the impact of variable rations on ruminal pH, NH3, VFA, total gas and methane concentration and enzymatic activity in steers consuming rations of fine- vs coarse-rolled corn and 20% vs 40% DDGS (Experiment 4) and corn vs barley based diets with low- vs moderate-oil DDGS (Experiment 5). Overall, nutrient restriction caused reduced BW, pancreatic mass and pancreatic enzyme activity in mature animals. In Experiment 1, the addition of dietary melatonin diminished the impact of nutrient restriction on maternal pancreatic mass and α-amylase activity while reducing the secretion of insulin and size of insulin-containing cell clusters. Fetal pancreatic enzymes were unaffected by treatment, however, pancreatic morphology exhibited greater insulin-containing cell cluster size in fetuses from adequately fed dams. In Experiment 2, arginine infusion did not alter pancreatic exocrine or endocrine function during the various luteal stage phases. In Experiment 3, realimentation during different stages of gestation decreased the impact of reduced feed intake and, in some cases, allowed for compensatory gain of the exocrine pancreas. The maternal and fetal endocrine pancreas was unaffected. Mature animals had greater changes in pancreatic exocrine secretions whereas fetuses differed mainly in endocrine function as a result of improper nutritional status. Comparison of pancreatic tissue revealed a greater quantity, and larger size, of insulin-containing cell clusters in fetuses which appear to separate as the animal matures. Differences in rumen enzymatic activity was found in Experiments 4 and 5, however, despite changes in lag time of gas production or ruminal degradation rates, the concentration of greenhouse gases (CH4 or CO2) produced were unaffected.
The Impact of Reproductive Technologies on Beef Cattle and Management
(North Dakota State University, 2016) Crosswhite, Mellissa
Two experiments were conducted to evaluate producer management decisions that may impact beef cattle reproductive efficiency. The over-arching hypothesis was that critical breeding management decisions would positively influence pregnancy rate, calving distribution, and calf weaning weights in crossbred beef cows. In experiment 1, the objectives were to assess two different breeding systems on reproductive and offspring outcomes in North Dakota beef herds, conduct partial budget analyses on each operation, and evaluate production, performance and profit outcomes within/across herds for each breeding system with the use of surveys, tests of knowledge, and focus group discussions. Cattle from 10 commercial beef herds were randomly assigned to one of two breeding systems: 1) only exposed to natural service herd bulls (CON), or 2) exposed to ovulation synchronization and fixed-time AI followed by natural service bulls (TAI, fixed-time artificial insemination). Producers were also enrolled in the Cow Herd Appraisal Performance Software and the Farm Business Management programs. A greater proportion of calves were born early in the calving season to cows exposed to TAI and subsequent calves were heavier at weaning compared to calves born from CON cows. Producer perceived understanding increased for every parameter tested by the end of the experiment. In experiment 2, the objective was to evaluate the use of an injectable trace mineral supplement on reproductive and offspring outcomes in North Dakota beef herds. Cattle from 4 commercial beef herds were randomly assigned to one of two treatments: 1) administered an injectable trace mineral supplement 30 d before breeding, or 2) administered no additional treatments prior to breeding. The injectable trace mineral supplement did not have any effect on pregnancy, weaning weights of calves at the side of cows, or calving distribution. Producers may be able to enhance profitability with the use of selected management strategies including the use of estrus synchronization and AI, record keeping and performance programs, and the inclusion of injectable trace mineral supplements. Selection of management strategies that fit individual operations will be key in terms of increasing profitability as well as decreasing stress of producers.
Impacts of Beef Cow Nutrition on Conceptus Development
(North Dakota State University, 2013) Camacho, Leticia Elideth
Two experiments were conducted to determine the effect of maternal nutrient restriction followed by realimentation during early to mid-gestation on uterine blood flow (BF), maternal performance, and conceptus development in pregnant beef cows. In Experiment 1, effects of maternal nutrient restriction followed by realimentation during mid-gestation on uterine BF of lactating, multiparous cows were evaluated. Nutrient restriction from d 30 until 140 of gestation did not alter total uterine BF. However, upon realimentation (from d 140 to 198 of gestation), there was enhanced ipsilateral uterine BF. In Experiment 2, effects of maternal nutrient restriction followed by realimentation during early to mid-gestation on late gestation uterine BF, maternal performance, and conceptus development was evaluated using non-lactating, multiparous cows. Slaughters were performed at d 85, 140, and 254 of gestation. During late gestation when all cows were receiving similar nutrition (100% of the NRC requirements), ipsilateral uterine BF and total BF were increased in cows that were previously nutrient restricted from d 30 until d 85 of gestation and realimented until d 254 of gestation. Therefore, results from both experiments suggest that the bovine placenta may be programmed to function differently after a period of nutrient restriction. Duration of restriction or realimentation impacted maternal performance and organ weights. The dam might become more efficient in the utilization of nutrients after being realimented as gestation advances. Nutrient restriction during early pregnancy tended to increase fetal and placental size by d 85. However, when cows were restricted longer or when realimented, there were no observable differences in placental or fetal growth. The maternal system may adapt to allow for fetal catch up growth during later gestation by enhancing uteroplacental nutrient transport capacity or placental function. From the results obtained in these 2 experiments we can conclude that maternal nutrient restriction during early gestation enhances conceptus growth and uterine BF later in pregnancy. Perhaps, timely management strategies might result in enhanced conceptus development. Even though more research is necessary, opportunities to intervene appear to be available during times of poor nutrition in beef cow/calf systems.
Independent Methods to Improve Meat Quality Including Genetic Technologies, Modified Processing, and Growth Promotants in Beef
(North Dakota State University, 2015) Schwartz, Christina Anne
Three independent studies were done to investigate how genetic factors, carcass management, and exogenous growth promotant programs influence meat quality attributes, palatability, and protein expression in beef. The first study involved Igenity® genetic profiling of myostatin sequence variants C313Y and Q204X of the myostatin gene in Piedmontese-crossbred heifers. Muscle from heifers having 1 or 2 copies of myostatin variants had decreased fat deposition, increased marbling, and minimal influence on quality attributes measured (tenderness and color), indicating a relationship between disruptive myostatin gene alterations and carcass and meat quality traits. Next, to improve the quality of the under-utilized beef round muscle, a modified hot-boning technique was utilized early post mortem to measure effects on meat palatability and myofibrillar protein degradation in deep and superficial portions of the beef semimembranosus (SM). Randomized treatments included deep SM hot-boned (DH) or cold-boned (DC), and superficial SM hot-boned (SH) or cold-boned (SC). Post mortem temperature and pH decline were monitored every 10 min for 24 h, and at 45 min, 3 h, and 24 h, respectively, in superficial and deep portions of the SM muscle. The deep SM had a slower chill rate and a more rapid pH decline when compared with the superficial SM, regardless of hot-boning treatment, which resulted in increased calpain 1 autolysis in deep SM when compared with superficial SM locations. Muscle from both deep SM treatments was less red, however, tenderness was not different among all treatments. Altering proteolytic activity and meat palatability is contingent upon the ability of the modified hot-boning technique to significantly alter temperature and pH decline in the deep portion of the SM. iv Lastly, proteomic technologies (two-dimensional in-gel electrophoresis coupled with mass spectrometry) were used to identify differentially abundant sarcoplasmic and myofibrillar proteins in the longissimus lumborum (LL) muscle from beef cattle treated with ractopamine hydrochloride with or without anabolic implant treatment during the finishing period. Exogenous growth promoting programs altered the protein profile of beef LL muscle, influencing the abundance of glycolytic enzymes and proteins possessing oxidative resistance, protective, regenerative, recovery, and anti-apoptotic properties that potentially effect meat quality or meat aging.
Influence of Cut, Cooking Method, and Post-Mortem Aging on Beef Palatability
(North Dakota State University, 2013) Lepper, Ashley Nicole
The objectives of these studies were to determine the effects of cut, cooking method, and postmortem aging on improving consumers' perception of beef. Consumers evaluated bottom round, top sirloin, ribeye, and a value cut samples for overall like, tenderness, juiciness, and flavor to understand how different cuts influence consumers' perception of beef characteristics. Consumers' rated the ribeye and value cut similar for overall like, tenderness, juiciness, and flavor. Bottom round steaks were rated the lowest for overall like and the toughest. Correlation and regression coefficients showed flavor was the largest influencing factor for overall like for the ribeye, value cut, and top sirloin. The value cut is comparable to the ribeye. Study two evaluated how different cooking methods (open-pan, oven bag, vacuum bag) influence the formation of warmed-over flavor (WOF) in reheated and fresh beef clod roasts (small, medium, large) utilizing a trained panel and thiobarbituric acid reactive substances (TBARS). Fresh vacuum bag and reheated open-pan roasts had higher cardboardy scores compared with fresh open-pan roasts. Brothy and fat flavors were higher in reheated roasts that were cooked in oven and vacuum bags. Lipid oxidation found fresh and reheated large and reheated medium roasts to have lower TBARS values. Presence of WOF can be prevented by cooking, storing, and reheating larger roasts in a cooking bag. Study three evaluated low marbled beef short and strip loins to determine the effect of post-mortem aging time (six aging periods) and type (wet and dry) on Warner-Bratzler shear force, slice shear force, and a trained panel. Slice shear force was not influenced by the aging parameters. As the days increased up to 35 d product was more tender, with days 35, 42, and 49 being similar. Panelists found similar results for tenderness up to 28 d of aging. Overall aged flavor was influenced by aging period, with days 42 and 49 having the numerically highest flavor scores, and dry boneless loins having more intense aged flavor. Beefy flavor was not influenced by aging. Aging regardless of method improves tenderness of low marbled loins, but neither method was able to improve beefy flavor.
Maternal Nutrition, One-Carbon Metabolites, and Programming of Fetal Development During Early Gestation
(North Dakota State University, 2019) Crouse, Matthew Scott Pennell
Crossbred Angus heifers (n = 14) were bred via AI, assigned to nutritional treatment (CON = 100% of requirements for 0.45 kg/d gain and RES = 60% of CON) and ovariohysterectomized on d 50 of gestation. Fetal liver, muscle from the hind limb, and cerebrum were analyzed by RNA-sequencing, and a total of 548, 317, and 151 genes, respectively (P < 0.01) were differentially expressed. Functional categories affected by nutritional treatment included: 1) Liver: metabolic pathways and nucleosome core, 2) Muscle: skeletal muscle and embryogenesis, and 3) Cerebrum: hippocampus and neurogenesis. Bovine embryonic fibroblast cells were cultured in Eagle’s Minimum Essential Medium with 1 g/L glucose (LOW) or 4.5 g/L glucose (HIGH). Control medium contained basal concentrations of one-carbon metabolites (Choline, folate, vitamin B12, and methionine). One-carbon metabolites (OCM: methionine, choline, folate, vitamin B12) were supplemented to the media at 2.5, 5, and 10 times (2.5X, 5X, and 10X, respectively) the control media, except for methionine, which was limited to 2X. One-carbon metabolites increased (P < 0.01) basal respiration and Reserve Capacity in HIGH 2.5X and 10X compared with all other treatments. ATP-linked respiration was greater (P < 0.01) in HIGH OCM supplemented cells compared to Control and was greater in LOW 2.5X compared with LOW Control, 5X, and 10X cells. Total growth rate was greater (P < 0.01) for HIGH 2.5X and 10X compared with LOW Control, 2.5X, and 10X. At 24, 36, 48, and 72 h, cell proliferation in HIGH 10X was always greater (P ≤ 0.03) than Low 10X. Therefore, these data are interpreted to imply that a moderate maternal nutrient restriction during the first 50 d of gestation in beef heifers alters the transcript abundance of genes impacting tissue accretion, function, and metabolism suggesting potential alterations to fetal physiology which should be further investigated. Lastly, supplementation of OCM may improve fetal growth and program increased metabolic efficiency in the offspring, and thus should be a focus of future research into the effects of maternal nutrition on postnatal physiology.
Maternal Nutritional Plane and Endogenous Retroviral Gene Elements, Pregnancy Hormones, and Placental Vascularity and Angiogenic Factors during the Establishment of Pregnancy in Beef Cattle
(North Dakota State University, 2016) McLean, Kyle James
In order to meet the projected food demands by 2050, animal agriculture must increase production of animal products on the same or decreased land area through increased efficiency. Early gestation is one area to increase efficiency in beef production in a twofold manner 1) by increasing the number of calves born due to decreased early embryonic loss and 2) by minimizing detrimental effects due to fetal programming which may decrease offspring growth or reproductive efficiency. Both of which will result in more pounds of beef produced by the same number of cows. Recently, endogenous retroviral elements (ERV), which make up a significant portion of mammalian genomes, have been implicated in vital steps during placentation. The placenta is the source of nutrient, gas, and waste exchange between maternal and fetal circulation which is necessary to support fetal growth. Maternal nutrition influences fetal growth and placental development. Therefore, we hypothesized that ERV envelope genes, syncytin-Rum1 and BERV-K1, as well as pregnancy specific hormones, PSP-B, and IFN-τ will be differentially expressed during critical time points of early pregnancy and maternal nutrition restriction will alter mRNA expression at critical time points. We developed a technique to ovariohysterectomized beef heifers which provides a large animal model to acquire uteroplacental tissues. In year 1, we established basal expression patterns for syncytin-Rum1 and BERV-K1, PSP-B, and IFN-τ within utero-placental tissues during the first 50 d of gestation. In year 2, we determined the effects of 40% global nutrient restriction on the mRNA expression of syncytin-Rum1 and BERV-K1, PSP-B, and IFN-τ on d 16, 34, and 50 of gestation in uteroplacental tissues. These data provide novel evidence of differential expression of endogenous retroviruses (syncytin-Rum1 and BERV-K1), PSP-B, and IFN-τ during early gestation but 40% maternal nutrient restriction had little influence of mRNA expression. However, further work needs to be completed to elucidate functions, mechanisms, and interactions of these genes during early gestation and their importance to the successful establishment of pregnancy.

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