bluuebunny/crossref_metadata_2025 huggingface dataset:
183 Ramped Piglet Housing During the Nursery Phase Increases Speed of Loading During Transportation to Market
Authors: Kasakamu Mary L , Young Jennifer M , Samuel Ryan S , Wagner Sarah A , Byrd Christopher J
Published: October 2023

Transportation is an essential component of commercial swine production in the United States. However, the process of transportation, including loading and unloading onto trailers, is a stressful experience for market hogs that results in poor welfare outcomes and substantial economic losses. Therefore, strategies intended to improve the transportation process should be developed. The objective of this study was to determine whether early-life exposure to a ramp structure during the nursery period would affect the ease of loading onto a standard swine trailer at the time of marketing. Weaned pigs (n = 560; 17 to 21 d of age) were penned in groups of 26 and randomly assigned to 1 of 2 treatment groups: 1) RAMP (housed in a standard commercial grow-finish pen furnished with a ramp and platform), or 2) CONTROL (standard commercial grow-finish pen with no ramp and platform). After 6 weeks, the ramps and platforms were removed from the RAMP pens and all pigs were housed under normal commercial conditions until they were marketed over 6 loadout days. After pigs in the barn began reaching market weight at approximately 5 months of age, pigs were moved by treatment in groups of 4 and loaded onto a pot belly livestock trailer (trailer and trucker were the same each time). Additionally, the person moving the pigs up the ramp was the same for all loading dates. The total amount of time it took for each group to navigate the ramp leading to the trailer was determined. Data were analyzed using the mixed procedure of SAS (v. 9.4) with total ramp navigation time as the dependent variable. Fixed effects included treatment, day of loading, and their interaction. A repeated measures statement with pen as the subject was included in the model to account for pen as the experimental unit. Overall, RAMP groups required less time to navigate the ramp onto the trailer than the CONTROL groups (69.12 ± 5.39 s vs. 95.11 ± 5.27 s; P = 0.002). Day of loading also affected ramp navigation time (P = 0.004). Specifically, navigation time on day 1 was greater than all remaining loading days (P < 0.05). Additionally, navigation time on day 2 was greater than day 6 (P = 0.02). No interaction between treatment and day of loading was observed (P = 0.41). In conclusion, exposing pigs to ramp structures within their pens during the nursery phase of production improves the loading speed at market weight by removing novelty associated with the loading ramp. Future research on this topic should incorporate additional behavioral and physiological measures to determine whether exposure of nursery pigs to ramps lowers stress and reduces the likelihood of injury during the transportation process at market weight.
184 Genetic Parameters for Human-Directed Behavior and Intraspecific Social Aggression Traits in Growing Pigs
Authors: Calderon Diaz Julia A , Desire Suzanne , Lewis Craig , Roehe Rainer , Turner Simon Turner
Published: October 2023

This study aimed to estimate heritabilities and genetic and phenotypic correlations for human-directed behavior and intraspecific social aggression traits in growing pigs, and to explore genetic and phenotypic correlations among them. Pigs (n = 2,314) were mixed into groups of 18 animals at 69 ± 5.2 d of age and skin lesions (SL) were counted 24 h (SL24h) and 5 weeks (SL5WK) post-mixing. Individual behavioral responses to isolation in a weighing crate (CRATE, 1 = pig performing exploratory behavior to 4 = pig performing serious, persistent attempts to escape) or when alone in an arena while a human directly approached them (IHAT) were assessed within 48 h post-mixing. During the IHAT, three separate scores were given for each pig based on the severity (0 = none to 3 = severe reaction) of their movement, vocalizations, and vigilance. Additionally, pigs were tested for behavioral responses to the presence of a single human observer walking in their home pen in a circular motion (WTP) within 1 and 4 weeks post-mixing recording pigs that followed, nosed or bit the observer. An animal model was used to estimate genetic parameters for all studied traits using the DMU software. Heritabilities (h2) for SL, CRATE and IHAT responses were low to moderate (0.17 to 0.29), with the greatest h2 estimated for speed of moving away from the approaching observer in the IHAT. Low but significant h2 were estimated for nosing (0.09) and biting (0.11) the observer at 4 weeks post-mixing in the WTP test. Positive high genetic correlations (rg) were observed between CRATE and IHAT responses (0.55 to 0.90), and within SL traits (0.60 to 0.94) while positive low to high rg were estimated within the WTP test (0.24 to 0.59) traits. Positive moderate rg were observed between CRATE and central and posterior SL24h. Genetic correlations between CRATE and IHAT test responses and WTP test traits were low, mostly negative (-0.21 to 0.05) and not significant. Low positive rg (0.06 to 0.24) were observed between SL and the WTP test traits except for the lack of rg between posterior SL24h and pigs biting or following the observer during both tests. Phenotypic correlations between CRATE and IHAT responses and SL or WTP test traits were mostly low and not significant. Under the conditions of this study, h2 estimates for all studied traits suggest they could be suitable as a method of phenotyping aggression and fear and/or boldness in pigs for genetic selection purposes. Additionally, there was evidence of genetic associations between aggression and fear indicators. These findings suggest applying selection pressure to reduce the accumulation of lesions is likely to make pigs more relaxed in a crate environment, but to alter the engagement with humans in other contexts that depends on the location of the lesions under selection.
185 Effect of ad Libitum Versus Limit-Feeding Program at Receiving on Morbidity and Performance of Feedlot Calves
Authors: Funk Rebecca A , Troyer Braden C , Norman Mitchell M , McPhillips Levi J , Erickson Galen E
Published: October 2023

Despite advancements in both vaccine technology and antibiotic therapy, bovine respiratory disease complex (BRD) remains the primary health challenge for cattle feeding operations in the United States. The strategy of limit-feeding calves during the early receiving period (first 28 days) has been proposed as a method to mitigate BRD risk, but limited data are available despite this strategy becoming more common. The objective of this study was to evaluate limit-feeding as a receiving protocol to determine impact on pull rates, receiving performance, and subsequent (Post-receiving) finishing performance. Steers (initial BW = 262 kg; n = 704) were blocked by arrival day (7 blocks) and housed in 44 open-lot pens. Pens were assigned to either limit-fed at approximately 75% of ad libitum or fed ad libitum for the 28-day receiving period. A subset of 216 steers in 14 pens was followed through finishing to evaluate carry-over effects in the finish period (192 days). Dry matter intake (DMI; P < 0.01), average daily gain (ADG; P < 0.01) and ending body weight (P < 0.01) were less for the limit-fed treatment compared with ad libitum due to the limitation of intakes as designed. Intake averaged 70.1% for limit-fed versus ad libitum whereas ADG was 72.6% for limit-fed compared with ad libitum. Because both DMI and ADG were decreased by similar amounts, G:F was not affected (P = 0.28). Numerically better G:F was observed for limit-fed cattle versus ad libitum but this 3.4% difference was not significant (P = 0.28). Morbidity rates for BRD were not statistically different, with ad libitum morbidity of 16.3% compared with 14.3% for limit-fed steers (P = 0.58) Low mortality for the receiving period was observed with 0.84% (3 steers) on limit-fed treatment, and 0% for the ad libitum treatment. For the subset of pens that were followed through finishing, there were no differences (P > 0.18) in ADG or DMI. While not statistically different, there was a 2.2% increase in ADG for steers that were limit-fed during the receiving period, which allowed for similar HCW and final BW (P = 0.39) at slaughter. Other carcass characteristics were also similar (P > 0.74) between steers received with an ad libitum or limit-fed program. No statistical difference (P = 0.29) in the rate of liver abscess occurrence was noted. In conclusion, there was no statistical difference between treatments in early-period morbidity or finishing performance between ad libitum and limit-fed receiving management.
186 Examining the Vaginal Microbiome During Gilt Reproductive Development
Authors: Fowler Emily , Dierking Shannon L , Levesque Crystal L , St-Pierre Benoit
Published: October 2023

Gilt reproductive failure is a common challenge in the US swine industry. Indeed, as many as three million breeding females are removed from swine herds each year, resulting in an annual replacement rate of 40%. Furthermore, about 20% of gilts selected for replacement never successfully enter the reproductive herd. The vaginal microbiome may play a role in gilt reproductive success; this study compared the vaginal bacterial composition from eight gilts at two pre-pubertal time points (d70 and d130 of age). Vaginal swabs were collected and analyzed using the 16S rRNA gene through PCR-amplification of the V1-V3 regions from vaginal microbial genomic DNA, followed by Illumina MiSeq 2X300 sequencing. Seven of the gilts achieved first estrus between d 164 and d 190 days of age based on physical signs of vulva swelling and locked stance in the presence of a boar. One female had no visible signs of estrus before 210 d of age. Beta diversity analysis by PCoA revealed that samples clustered into two separate groups according to time points. Alpha diversity indices (Sobs, Ace and Chao) were numerically decreased between d 70 to d 130. A comparative analysis of the most highly represented Operational Taxonomic Units (OTUs) using the non-parametric Kruskal-Wallis sum-rank test and Wilcoxon pairwise test identified 12 OTUs that varied in abundance (P < 0.05) between the two time points. Notably, OTU SD_Ssd-00001, predicted to be a strain of Lactobacillus amylovorus (99.82% sequence identity), was greatest at d 70 (21.33%), then significantly decreased at d 130 (7.67%). In contrast, OTU SD_Ssd-01393, corresponding to an uncultured species of Prevotellaceae (closest relative: Prevotella disiens, 92.48%), was in less abundance at d 70 (4.87%), but became the most abundant OTU at d 130 (18.19%). The vaginal OTUs identified in this study included not only known bacterial species, such as members of the Lactobacillus genus which have been previously found to be normal and beneficial residents of the human vagina, but also uncharacterized bacterial species. These results are indicative of distinct vaginal microbiome composition between d 70 and d 130 of age and suggest that certain bacterial species could potentially be used as indicators of reproductive potential in gilts.
74 The Dynamic Animal Welfare Concept: A Guideline to Assess, Safeguard and Promote Animal Welfare
Authors: Arndt Saskia S , Goerlich Vivian C , Josef van der Staay F
Published: October 2023

Theoretical concepts are needed to guide and provide the basis for the appropriate assessment, protection and promotion of animal welfare. Due to its multifaceted nature, animal welfare can be approached from different perspectives, depending on ethical assumptions, human interests and culture. In the past, concepts of animal welfare have evolved from the Five Freedoms, which focused on the absence of negative conditions, to Quality of Life and the Five Domains, which emphasized the presence of positive conditions. We build on the existing theoretical framework and present here the Dynamic Animal Welfare Concept (DAWCon, Arndt et al.2022). Based on the adaptive capacity of the individual animal, DAWCon recognizes the dynamic nature of animal welfare and the importance of positive emotional states. We propose that an individual animal is likely to be in a positive welfare state when it is mentally and physically capable and has the ability and opportunity to respond appropriately to sporadic or persistent appetitive and adverse internal and external stimuli, events and conditions. Appropriate responses are elements of a normal behavioral repertoire of the animal. They enable the animal to cope with and adapt to the demands of the (Prevailing) environmental circumstances and to reach a state that it perceives as positive (i.e., that evokes positive emotions). In addition to presenting our conceptual approach, we will outline the issues that need to be considered when assessing welfare, emphasizing that welfare needs to be monitored over time. Animal behavior is highlighted as a key indicator and the role of normal and natural behavior is discussed. To ensure its welfare, an animal must respond and adapt appropriately to the net effects of appetitive and adverse factors. Examples of such internal and external factors and their potential to have sporadic and lasting welfare consequences are discussed. Reference: Arndt SS, Goerlich VC and van der Staay FJ (2022) A dynamic concept of animal welfare: The role of appetitive and adverse internal and external factors and the animal’s ability to adapt to them. Front. Anim. Sci. 3:908513. doi: 10.3389/fanim.2022.908513
17 Nutritional Consequences of Formulating pig Diets with Low Energy Values Using Fibrous Rich Byproducts
Authors: van Dijk Albert , Molist Francesc
Published: October 2023

The objective of this study is to provide insight in how to formulate pig diets in the most economical way in times of high feedstuff prices. Regarding this, energy level and the way of calculating energy in swine feeds will be taking into consideration, as well as the nutrients to energy ratios. Moreover, the effects of diet concentration on feed intake and growth performance of pigs will be evaluated. The lowest cost per energy value in swine feeds can be assessed by iterative simulations in least cost calculations using linear programming. In this case, a fixed nutrient to energy ratio has to be maintained for each cost per energy value that is calculated. Since feedstuff prices are subject to changes, these calculations have to be made on a regular basis. A dataset of 6 growth performance experiments in growing finishing (GF) pigs varying in energy values performed at Schothorst Feed Research (SFR) was analyzed. While decreasing the net energy value of the feed (at fixed nutrient to energy ratios), feed intake and energy conversion increased, while energy intake, daily gain and feed conversion ratio decreased. In general, pigs fed diets with reduced energy concentration are prone to maintain constant daily energy intake by eating more feed until feed intake is limited by other factors, such as physical gut capacity or certain dietary components (Li and Patience, 2017). In the same SFR analysis, the effect of the lysine (and other essential AA) to NE ratio was investigated. While decreasing this ratio, feed intake and energy intake were unaffected, while daily gain decreased, and the feed conversion ratio and energy conversion ratio increased. Another analysis of several GF experiments conducted at SFR was done to assess the optimal amino ccid (SID EAA) content of grower/finisher pig feeds in relation to technical performance, carcass characteristics and profitability. It was concluded that decreasing the SID AA/NE ratio to a certain extend will decrease technical performance (ADG and lean meat %) but increase economical results. However, it must be taken into account that optimal economic performance depends on market situation (feedstuff prices) and production goals (optimal ADG, carcass quality or costs/kg pork). In the current situation with high feedstuff prices, the inclusion of fibrous rich byproducts in the Dutch market may be more economical than corn and soybean meal. For an optimal estimation of the proportion of energy of those fibrous byproducts that will be attributed to the growth and maintenance energy requirements of the pigs, the net energy system is more appropriate than the metabolizable energy (ME) system, because the ME system overestimates the proportion of energy that will be used for growth and maintenance.
100 Pedigree Effective Population Size Affects Genomic Prediction Accuracy in Katahdin Sheep
Authors: Nilson Sara M , Burke Joan M , Lewis Ronald M
Published: October 2023

Katahdin sheep are a composite hair breed of medium-size, relatively prolific, with potential to exhibit resistance to gastrointestinal parasites. Recently, genomic predictions of breeding values were introduced in Katahdins. Prediction accuracy depends on the genetic variation present, and selection using genomically-enhanced breeding values may reduce diversity. We aimed to characterize the current genetic variability in Katahdins utilizing their extensive pedigree. The National Sheep Improvement Program provided the pedigree of 92,030 sheep born from 1984-2019. Two reference populations were defined for animals born between 2017-2019: all Katahdins (n = 23,494), and Katahdins with at least three generations of known Katahdin ancestry (n = 9,327). Using ENDOG and PopReport, effective population sizes (Ne) were estimated. We then considered the effect of Ne on the size of the genomic reference population needed to achieve certain levels of prediction accuracy. Weaning weight, a lowly heritable trait for this breed (h2 = 0.13), was evaluated. Based on individual increase in inbreeding, inbreeding coefficient of animal adjusted for equivalent complete generations, the estimated Ne for the full pedigree, reference 1, and reference 2 were 92, 104, and 87, respectively. When inbreeding coefficients were regressed or log-regressed on birth date and adjusted for generation interval, the Ne estimates were 53 and 49 for reference 1, and 76 and 67 for reference 2, respectively. For our average Ne = 75 with 3,960 effective chromosomal segments, the accuracy of prediction for weaning weight was estimated for genomic reference population sizes (N) of 10k, 15k, 20k, and 25k. Starting at N = 10k, the prediction accuracy was 0.58, and as N increased by 5k increments the accuracy increased to 0.65, 0.70, and 0.74. Conversely, with our smallest Ne = 49 with 2,548 effective chromosomal segments, the prediction accuracy was 0.64, 0.71, 0.75, and 0.78 for N = 10k, 15k, 20k, and 25k, respectively. Estimated Ne varied depending on the method utilized, and tended to be larger for reference 1 than 2. However, this was not the case for Ne based on regression. Inbreeding coefficients were greater in reference 2 than 1, and the generation interval was shorter in reference 2 (2.84 years) than in 1 (2.97 years). These combined differences led to larger Ne estimates for reference 2 than 1, reflecting the impact of different criteria used to obtain this statistic. The generally small, estimated Ne benefitted genomic prediction due to a greater shared number of effective chromosomal segments. Investing in larger genomic reference populations will only marginally increase prediction accuracy even for lowly heritable traits. Selection using genomically-enhanced breeding values will accelerate genetic gains, potentially reducing the Ne of Katahdins and thereby increasing prediction accuracy. Yet, long-term gains may be at risk due to the loss of genetic diversity.
178 Functional Role of Regulatory Elements Informs Complex Trait Variation and Domestication Selection in Farm Animals
Authors: Zhou Huaijun
Published: October 2023

Functional Annotation of Animal Genomes (FAANG) has made significant progress on the improvement of the annotation of the functional elements, particularly non-coding regions in farm animal genomes. Different epigenomes including ChIP-seq for 4 histone marks, ATAC-seq, CTCF-seq, RNA-seq, and Hi-C across different tissues were generated. Thousands of cis-regulatory elements including promoters and enhancers across different tissues in different species were identified and annotated. A comprehensive characterization and comparison of cis-regulatory elements across tissues and species can help us understand the genetic and evolutionary basis of complex phenotypes. We demonstrate that genomic variants associated with complex traits and adaptive evolution in farm animals are significantly enriched in active promoters and enhancers. Furthermore, we reveal distinct tissue-specific regulatory elements play important roles in domestication processes. Finally, we provide biological insights on tissue-specific regulatory conservation, and by integrating genome-wide association studies on complex traits, we demonstrate that cis-regulatory elements annotation enhances our interpretations of complex traits variations in farm animals.
57 Concentration of Digestible Energy in Corn-Based Diets Fed to Gestating and Lactating Sows is Increased by Adding Xylanase to the Diets
Authors: Medellin Jessica P Acosta , Espinosa Charmaine D , Ortiz Gemma Gonzalez , Stein Hans H
Published: October 2023

The hypothesis that exogenous xylanase added to diets for gestating and lactating sows will increase the apparent total tract digestibility (ATTD) of gross energy (GE) and total dietary fiber (TDF), and digestible energy (DE) and metabolizable energy (ME) was tested. Two diets for gestating and two diets for lactating sows containing corn, soybean meal, distillers dried grains with solubles, wheat middlings, and soybean hulls were formulated without or with 16,000 BXU per kg of exogenous xylanase (Econase XT; AB Vista, Marlborough, UK). Lactation diets contained an indigestible marker. Diets were fed to gestating and lactating sows in two reproductive cycles. A total of 106 gilts and sows were randomly allotted to the two gestation diets 7 d after breeding in a randomized complete block design with 4 blocks. On d 30 post-breeding, 8 non-pregnant animals were removed. From the remaining 98 animals, 48 sows (24 replicates per treatment, 12 sows per block) were placed in metabolism crates on d 35 (mid-gestation) for 10 d with feces and urine collected for 5 d. The same 48 sows were placed in metabolism crates again on d 95 (late-gestation). All sows were moved to the lactation unit on d 106 and lactation diet feeding was initiated. Fecal samples were collected (grab-sampling) for 5 d starting on d 10 post-farrowing. Sows were weaned on d 20 and 63 sows were rebred. Of these sows, 46 sows were placed in metabolism crates on d 35 and 95 as in the first cycle, and treatments in the farrowing unit were also as in the first cycle. Data were analyzed using the MIXED procedure of SAS with sow as the experimental unit, diet as fixed effect, and block and replicate as random effects. Results indicated that in the first cycle, the ME in mid-gestation, and the ATTD of TDF, and DE and ME in late-gestation were greater (P < 0.05) in sows fed the xylanase-diet compared with the control diet (Table 1). During the first lactation period, sows fed the xylanase-diet had greater (P < 0.05) ATTD of TDF and GE and greater (P < 0.05) DE than sows fed the control diet. During the second gestation period, sows fed the xylanase-diet had greater (P < 0.05) DE and ME in mid- and late-gestation, but no differences were observed in ATTD of TDF (Table 2). During the second lactation period, sows fed the xylanase-diet had greater (P < 0.05) ATTD of TDF and GE and greater (P < 0.05) DE than sows fed the control diet. In conclusion, DE was greater in the xylanase-diet than the control diets during two reproductive cycles, and sows fed lactation diets with xylanase had greater digestibility of fiber.
52 Feeding Style and its Effect on Growth and Spatial Preference of Young Pigs
Authors: Sommer Kaitlyn , Senthill Pradeep , Joung Sangyun , Golden Rebecca , Dilger Ryan N
Published: October 2023

In this study we investigated the effects of feeding method on growth performance and spatial preference within the home-cages (HC) of young pigs. Pigs (n = 41 boars) were weaned at postnatal day (PND) 2, allotted to treatment controlling for litter and body weight (BW), and reared artificially over a 15-d period. Pigs were provided a nutritionally adequate milk replacer 20-h per day, dispensed in one of two ways: 1) ad libitum (continual access to milk replacer), and 2) prescribed [330 mL/kg of BW from PND 3-7 (week 1), and 357.5 mL/kg of BW from PND 8-18 (week 2)]. In addition to water in the reconstituted milk replacer, free choice access to water was provided throughout the study. Milk intake (i.e., disappearance) and BW were recorded daily, with pigs undergoing continuous video surveillance throughout the study. Video analysis of pigs (n = 6) was performed to establish time spent in each HC quadrant (Table 1). All data were analyzed via a 2-way ANOVA (feeding style vs. home-cage quadrant) using the MIXED procedure of SAS. During week 1, pigs in the ad libitum treatment had increased (P < 0.05) average daily gain (219 g/d) and average daily milk intake (1,014 g/d) compared with the prescribed treatment (183 g/d and 794 g/d, respectively). This same effect continued in week 2 for average daily milk intake, with ad libitum-fed pigs consuming more (P < 0.05) milk replacer (780 g/d) compared with prescribed-fed pigs (614 g/d). Ad libitum-fed pigs exhibited better (P < 0.05) feed efficiency [i.e., reduced G:F ratio (0.22 and 0.19, respectively)] compared with prescribed-fed pigs (0.24 and 0.21, respectively) during both weeks 1 and 2. Over the entire 15-d feeding study, average daily gain (253 g/d) and milk intake-to-BW ratio (0.59) were greater (P < 0.05) in the ad libitum treatment compared with prescribed feeding (206 g/d and 0.52, respectively). Video analysis of spatial preference within HC suggested pigs spent more (P = 0.08) time in quadrants 2 and 4 (33.6% and 35.5% of time recorded, respectively), likely due to proximity to the feeding bowl, compared with quadrant 3 (8.7% of time recorded) but this effect did not differ (P = 0.50) by feeding method. Overall, type of feeding style altered growth performance within young pigs and may impact the spatial preference of pigs within their home-cage environment.
41 Growth Performance and Carcass Characteristics of Beef-Sired Steers Born to Holstein Dams
Authors: Basiel Bailey L , Felix Tara L
Published: October 2023

The objective of this study was to compare feedlot growth performance and carcass characteristics of F1 beef × Holstein steers (n = 124) sired by commercially available Angus (n = 19 from 7 sires), Charolais (n = 79 from 3 sires), SimAngus (n = 16 from 3 sires), or Wagyu (n = 10 from 2 sires) bulls. Male calves born from May to August of 2021, were sourced from 8 Pennsylvania dairy herds. Steers were raised by a commercial calf grower until April of 2021 (10.5 ± 1.5 months of age). Steers were then moved to the PA Department of Agriculture’s Livestock Evaluation Center (LEC) and transitioned to a high-energy ration. Individual feed intake was monitored using the GrowSafe Feed Intake Monitoring System (Model 4000E, Vytelle, Calgary AB, Canada). Steers were slaughtered after 90, 118, or 153 days on feed at the LEC. Pulls were based on a combination of visual appraisal and body weight. Linear models of growth performance traits and carcass characteristics included the fixed effects of sire breed, herd of origin, and birthdate. Binomial models of USDA Quality Grades and Yield Grades included a fixed effect of sire breed. Angus-sired steers were heaviest at feedlot entry (P < 0.01) and were on feed for the fewest days (P < 0.01). Angus × Holstein steers were heavier at slaughter (P < 0.01) than SimAngus and Wagyu-sired steers. Wagyu-sired steers had the least dry matter intake (DMI), average daily gain (ADG), and carcass ADG (P < 0.01) when compared with progeny of other sire breeds. No differences in gain to feed intake (G:F(; P = 0.90), back-calculated carcass G:F (P = 0.62), net energy of metabolism (P = 0.70) and net energy of gain (P = 0.70), nor hip height at harvest (P = 0.14) were detected between sire breeds. Wagyu × Holstein carcasses were the lightest (P < 0.01) and had the least amount of backfat (P = 0.01). Dressing percentage tended to be least (P = 0.10) in Charolais × Holstein carcasses (60.5%) and greatest in SimAngus × Holstein carcasses (61.7%); carcasses from Angus and Wagyu-sired steers were intermediate and not different. About 84% of Angus × Holstein carcasses graded Choice while only 31% of SimAngus × Holstein carcasses graded Choice (P = 0.03). However, there were no differences in called marbling scores between sire breeds (P = 0.15). Charolais × Holstein tended to have the lowest proportion (4%) of Yield Grade 1 carcasses (P = 0.05). Angus-sired steers were on feed for the fewest days when compared with steers sired by other beef breeds. Wagyu × Holstein steers had reduced ADG, DMI, and subsequent carcass weight in comparison with compared steers of other sire breeds.
49 The Effect of Increasing Standardized Ileal Digestible Methionine Intake During Lactation on Whole-Body Nitrogen Utilization of Primiparous Sows
Authors: Kozole Cierra , Alfonso Cristhiam J Munoz , Htoo John K , Huber Lee-Anne
Published: October 2023

Seventy-five primiparous Yorkshire × Landrace and Yorkshire sows were used to determine the effect of increasing dietary standardized ileal digestible (SID) methionine (Met) intake on whole-body nitrogen (N) utilization during lactation. Upon farrowing (190.2 ± 18.0kg initial body weight), sows were assigned to 1 of 7 dietary SID Met levels (n = ~10), ranging from 70% to 130% of estimated SID Met requirements (0.182 to 0.338% SID Met) via the addition of DL-Met. All other indispensable amino acids were supplied above estimated requirements (1.19% SID lysine, 19.74% crude protein) and additional cysteine was supplied to minimize Met utilization for transsulfuration. Litters were standardized to 13 ± 2 piglets within 48 hours of birth and feed was offered according to a standard feeding curve (NRC, 2012). The N balance periods were between days 5 to 9 (early; N1) and 17 to 21 (Peak; N2) of lactation where total urine was collected via urinary catheters and feces was grab-sampled; titanium dioxide was used as an indigestible marker for determining apparent total tract N digestibility. In N1 and N2, 5.22 and 6.87 kg/d of experimental diet was offered in three equal meals at 0830, 1200, and 1530 h to each sow. Milk N output (g/d) was calculated using estimated milk yield based on litter growth rate and size and analyzed milk N concentration. Contrast statements were used to assess linear and quadratic effects of dietary SID Met level. During N1, N intake increased and then decreased when dietary SID Met content surpassed 0.286% (quadratic; P < 0.05). Similar relationships were observed for total N excretion (urine + fecal N; P < 0.05) resulting in no SID Met effect on N retention (77.1 ± 6.6, -12.5 ± 10.4, and 89.5 ± 8.9 g/d for total, maternal, and true milk protein N retention, respectively) or apparent N utilization efficiency (N retention/N intake×100; 53.2 ± 3.4%). During N2, as SID Met increased, N intake tended to increase (205.5 to 210.2 ± 5.7g/d; linear; P = 0.078), total N excretion tended to decrease (87.3 to 78.7 ± 6.2 g/d; linear; P = 0.087), and total N retention increased (117.9 to 131.4 ± 8.0g/d; linear; P < 0.05). True milk protein N output increased with SID Met (100.3 to 112.5 ± 8.1 g/d; linear; P < 0.05) and maternal N retention decreased and then increased when dietary SID Met content surpassed 0.260% (quadratic; P < 0.05). Apparent N utilization efficiency increased with increasing dietary SID Met (57.5 to 62.5 ± 1.2%; linear; P< 0.05). Therefore, in early lactation, SID Met intake had minimal effects on N utilization, indicating that the requirement for lactating primiparous sows may be equal to or less than 0.182% SID Met. During peak lactation, the supply of SID Met needed to maximize true milk protein N and apparent N utilization efficiency may be greater than 0.338%, which does not take into consideration the non-protein partitioning of dietary Met.
43 Impact of Pregnancy Status on the Transcriptome of Peripheral White Blood Cells
Authors: De Santos Jorge A Los , Andrade João Paulo N N , Iriarte Andres , Penagaricano Francisco , Parrish John J
Published: October 2023

Most embryo losses occur in the first trimester of pregnancy in cows, resulting in negative economic impact for dairy production systems. The current scientific paradigm implies the conceptus evades rejection by the maternal immune system. However, the cellular and molecular mechanisms behind the maternal immune response to the growing embryo have not been fully characterized. Hence, this study examined gene expression profiles of peripheral white blood cells (PWBC) from pregnant cows at 21 days after an embryo was transferred, (Bos taurus taurus), and cows that were treated equally but lost the embryo. We investigated the effect of pregnancy status on differential gene expression in PBMCs. We obtained and compared the total transcripts of PWBC from heifers that became pregnant at day 21 (N = 5) or failed to become pregnant after the embryo transfer (N = 5t). The total RNA transcripts, where an average of 96 % of the total reads were successfully mapped to the bovine reference genome. Each sample generates between 32 to 43 million reads. Sequencing data can be accessed by GEO with the accession number GSE210665. There was no need to remove samples in this study. Based on the length and abundance of the reads that cover the bovine genomic, we conclude that deep sequencing is suitable for the experiment outcome. A total of 13.167 genes were tested for differential expression by controlling the false discovery rate (FDR). A positive fold change denotes an overexpression and a negative fold change value a downregulation gene between treatments. After statistical analysis, 682 of these genes present a P-value smaller than 0.01, a total of 302 genes were upregulated, and 382 downregulated. The top 7 expression fold change top upregulated (logFC > 2) genes were COL1A2, LOC100337213, H2AC18, HTRA1, MMP14, CD5L, and LOC100297044. The top 4 downregulated (logFC< − 2) were ADAMDEC1, MYO1A, RPL39, and Histone H4. These data show differentially expressed genes associated with pregnancy status were both upregulated and downregulated as a response to early pregnancy, or a failure to become pregnant after embryo transfer. Our results show that these are key maternal genes for promoting tolerance allowing developing of the embryo. In summary, this study presented the genes related to positive regulation of inflammatory chemokine activity and immune defense response in the maternal PWBC.
55 The Effects of Dietary Net Energy Levels on Grow-Finish Performance and Carcass Characteristics of Market Gilts Managed with Improvest
Authors: Wang Yifei , Hansen Blaine , Pollmann Steve , Landero Jose Luis , Young Malachy , Bohrer Benjamin M
Published: October 2023

Improvest is a gonadotropin releasing factor (GnRF) analogue-diphtheria toxoid conjugate injection approved for temporary suppression of ovarian function and estrus in market gilts (Zoetis Canada Inc.). Study objectives were to determine the effects of three different net energy levels (LOW – 2.216 Mcal/kg, MID – 2.341 Mcal/kg, or HIGH – 2.466 Mcal/kg) during the grow-finish period on live performance and carcass characteristics of market gilts managed with Improvest (IMP) compared with market gilts not managed with Improvest (CON). The study consisted of 1,008 market gilts (average starting weight of 30.8 kg) in 48 pens (21 pigs/pen) with experimental treatments arranged as a 2 × 3 factorial design with main effects of Improvest (IMP or CON) and net energy level (LOW, MID, or HIGH). An equal number of pigs were marketed from each of the six treatment groups on day-83 (21.9% of the population), day-90 (21.9% of the population), day-97 (21.9% of the population), and day-104 (34.3% of the population) of the experiment. The weighted average for time post-second Improvest injection to marketing was 39.8 days. Data were analyzed with PROC MIXED of SAS, with pen serving as the experimental unit, fixed effects of Improvest (IMP or CON), net energy level (LOW, MID, or HIGH) and their interaction, and a random effect of pen location. There were no significant interactions (P ≥ 0.20) for average daily feed intake (ADFI), average daily gain (ADG), Feed:Gain (F:G), hot carcass weight (HCW), dressing percentage, backfat thickness, or predicted lean yield. However, IMP gilts consumed more feed (6.8% greater ADFI; P < 0.01), grew faster (5.0% greater ADG; P < 0.01), were less efficient (1.5% greater F:G; P < 0.01), were heavier (3.5 kg HCW; P < 0.01), and were fatter (1.9 mm greater backfat thickness and 0.9% less predicted lean yield; P < 0.01) than CON gilts. No difference (P = 0.21) in carcass dressing percentage between IMP and CON gilts was detected (Table 1). There were significant effects (P < 0.05) of net energy level for ADFI, ADG, F:G, HCW, and dressing percentage. Pigs fed LOW diets had the greatest ADFI, slightly less ADG, the least efficient F:G ratio, the lightest HCW, and reduced dressing percentage compared with HIGH (P < 0.01). There were no differences (P > 0.05) for backfat thickness or predicted lean yield among dietary energy level treatments. Overall, these data indicate that typical Improvest response levels were sustained at each of the net energy levels evaluated in this study (response levels for HCW of 2.6 kg for LOW, 3.4 kg for MID, and 4.5 kg for HIGH); however, consideration should still be provided to the known production impacts of low net energy diets when market gilts are managed with Improvest.
47 Feeding Pigs with Low Crude Protein Diets: Impact of Pig Manure Nitrogen Content on Biogas Production and Digestate Quality
Authors: Hickmann Felipe M W , Andretta Ines , Cappelaere Léa , Goyette Bernard , Létourneau-Montminy Marie-Pierre , Rajagopal Rajinikanth
Published: October 2023

Lowering dietary crude protein levels is a nutritional strategy recognized to both decrease the use of high-impact feed ingredients and reduce nitrogen (N) excretion. Improved pig manure management practices can further mitigate the environmental impacts associated with pig production towards net-zero emissions. Anaerobic digestion (AD) is a promising technology for transforming pig manure into energy as biogas and into bio-based fertilizers (i.e., digestate from AD). However, little is known about the effects of pig manure N content on AD. Thus, this study aimed to evaluate the impact of pig manure N content on biogas production and digestate quality through the AD of manure from pigs fed low crude protein diets. Three pig manure N concentrations were tested: T1 = 5873, T2 = 5421, and T3 = 5149 total Kjeldahl nitrogen (TKN, mg/L). Throughout 5 sequential fed-batch cycles (25 ± 4 days/cycle), biogas production and its composition (CH4, CO2, and H2S) were measured, while raw manure and weekly digestate samples were analyzed for total solids (TS, %), volatile solids (VS, %), pH, chemical oxygen demand (COD, mg/L), TKN, and ammoniacal nitrogen (NH3-N, mg/L). In a temperature-controlled room (20 ± 1ºC), 6 digesters (3 treatments x 2 replicates) were operated as single-stage reactors to digest pig slurry (mixture of urine and feces, TS: 5.6%) inoculated with a liquid inoculum (TS: 2.3%) to improve manure-microbe interactions. Data were analyzed by ANOVA using PROC MIXED with repeated measures and comparison of means through the Tukey test (SAS software). In addition, both correlation and regression analyses were performed with R to evaluate the relationship among variables. Decreasing pig manure N content showed a tendency to reduce biogas (-20% in T3 vs T1; P = 0.0782) and methane (-22% in T3 vs T1; P = 0.0576) production per cycle, as shown in Table 1. Regarding biogas composition, CH4/biogas and CH4/CO2 decreased with N content (-3 and -4% in T3 vs T1; P ≤ 0.0082). There were strong positive correlations between the N content of pig manure and the amount of NH3-N (linear: r = 0.94, R2 = 0.88) and TKN (linear: r = 0.90, R2 = 0.81) present in the digestate at the end of each cycle. These results suggest that a reduction in pig manure N content reduces biogas production and its quality (ratio of CH4 to CO2). This latter variable is important for biogas efficiency; thus, reducing crude protein in pig diets may impair the production of biogas in AD. However, a decreased N content may cause less emissions into the environment, but when using the digestate as fertilizer, it may not entirely fulfill the N requirements of fast-growing crops for a given application rate.
53 Effect of Vitamin A Supplementation During Gestation on Vitamin A Status of Beef Cows and Their Calves Managed in the Drylot
Authors: Speer Hannah , Wilke Karla , Drewnoski Mary E
Published: October 2023

Cows fed diets consisting primarily of stored forages and concentrates may be at risk for vitamin A deficiency because these feedstuffs are low in β-carotene. Furthermore, dietary vitamin A concentrations of the cow during late gestation will affect vitamin A concentrations in colostrum, which calves rely on at birth to supply vitamin A. The objective of this study was to evaluate how level of vitamin A supplementation from mid-gestation to early lactation affected cow and subsequently, liver retinol concentrations of their calf. Multiparous beef cows (n = 54) were stratified by body condition score and previous source and assigned to pen (n = 9); 3 pens were assigned to each of the following treatments: current NASEM recommendation (31,000 IU/d; 1X), 3 times (93,000 IU/d; 3X), or 5 times (155,000 IU/d; 5X) the current NASEM recommendation for supplemental vitamin A. Cows were limit-fed a diet consisting of wheat straw, corn silage, and wet distillers grains. Liver biopsies were collected on cows 3 weeks before treatment initiation, d 40 and d 81 of supplementation, and both cows and calves were sampled 32 days post-calving (165 ± 22 d SD of supplementation). No differences (P=0.86) in initial cow liver retinol (mean 186 µg/g DM) were observed between treatments. A significant treatment × day interaction (P < 0.01) was observed for cow liver retinol. On d 40, cows in 1X had liver retinol concentrations (178 µg/g DM) that were not different (P = 0.12) from 3X (213 µg/g DM) but less (P = 0.02) than 5X (241 µg/g DM), while 3X and 5X did not differ (P = 0.21). Liver retinol on d 81 was less (P < 0.05) in 1X (189 µg/g DM) compared with 3X (334 µg/g DM) and 5X (412 µg/g DM), which did not differ (P = 0.20). For cow liver retinol post-calving, 1X (187 µg/g DM) was less (P< 0.05) than 3X and 5X, and 3X (454 µg/g DM) was less (P< 0.05) than 5X (674 µg/g DM). Liver retinol concentrations of 1X cows remained below adequate reference ranges (300–700 µg/g of DM) throughout the study, whereas 3X and 5X were increased into the adequate range by d 81. Calf liver retinol concentration also differed among treatments (P = 0.01), as calves of cows in 1X had less (P < 0.05) liver concentrations than 3X and 5X calves which did not differ (P=0.12). Liver retinol concentrations considered adequate for calves at 32 days of age (100–350 µg/g of DM) were not observed in 1X calves (51 µg/g DM) but were observed in calves from 3X and 5X cows (119 and 165 µg/g DM, respectively). Supplementing cows with 93,000 IU/d of vitamin A for 165 days brought liver retinol concentrations of cows and their calves up within adequate reference ranges.
194 A Systems Approach to Deriving Carcass Value from Holstein x Simangus Cattle in an Accelerated Finishing Model
Authors: Schnurbusch Teagan , Brake Derek W , Petzel Emily A , Callahan Zachary D , Poock Scott E , Wiegand Bryon R
Published: October 2023

Crossbreeding dairy cows with beef sires has increased in the U.S. dairy industry. This beef x dairy mating results in dairy-beef which has altered the U.S. fed beef supply. The predominant mating has been Holstein x Angus, thus research was conducted to determine the effects of Holstein x SimAngus breeding on growth performance, carcass characteristics, and fresh meat quality. Starting on d 1, Holstein steers (n = 9) and Holstein x SimAngus (HolSim) steers (n = 12) were fed once daily at 0830 h, until an end weight of 635 kg was reached. Holstein steers averaged 421 d and HolSim steers averaged 432 days on feed. Daily feed offered was delivered into a semi-autonomous feed monitoring system designed to measure individual animal intake and feeding behavior (GrowSafe System Ltd). Steer body weight was recorded every 28 d. Data collected were used to calculate dry matter intake (DMI), average daily gain (ADG), and gain to feed ratio (G:F). Steers were humanely slaughtered under USDA inspection, immediately following slaughter hot carcass weight (HCW) was recorded and 48 h following slaughter, carcass length, body width, backfat thickness and area of the longissimus muscle (LM) was recorded. Strip loins were collected from each carcass and aged for 14 d. After aging, Warner-Bratzler shear force (WBSF) and slice shear force (SSF) were determined. Remaining steaks were placed under retail display for 7 d. Objective color was measured after 0, 1, 3, 5, and 7 d in retail display. No differences were observed for ADG and G:F between Holstein and HolSim steers (P > 0.05). A tendency was observed for Holstein steers to have a greater DMI compared with HolSim steers (P = 0.0646). The HolSim steers had greater HCW and dressing percentages compared with Holstein steers (P < 0.0001). The HolSim carcasses had shorter carcass lengths and body widths compared with Holstein carcasses (P = 0.0005). Holstein carcasses had less backfat compared with HolSim carcasses (P = 0.0034). The LM area was larger in HolSim carcasses (P < 0.0001). No differences were observed for WBSF or SSF (P > 0.05). Strip steaks from HolSim steers had less deoxymyoglobin and greater oxymyoglobin values on d 0 of retail (P < 0.05). Strip steaks from HolSim steers had greater a* and saturation index values on d 7 in retail (P < 0.05). Strip steaks from HolSim steers had decreased metmyoglobin values and greater oxymyoglobin values on d 7 in retail (P < 0.05). Thus, indicating strip steaks from HolSim steers had increased red color. Growth performance data in this study confirm previous literature reported when comparing dairy x dairy to beef x dairy steers. Carcass and fresh meat data suggest that Holstein x SimAngus steers had improved yield production compared with Holstein steers without a loss in quality when steers were fed to a weight constant end point.