Angus Heifer Research Articles

Perineal hernia in a pregnant Angus heifer (Bos taurus)

AbstractThis case report details a perineal hernia in a 3‐year‐old Angus heifer in late gestation. The heifer had a gradually increasing swelling of the perineal region since 2 weeks. Upon palpation, the swelling was painless, hard and non‐reducible. Ultrasonographic examination revealed a hernial sac enclosing the non‐pregnant horn of the uterus, filled with homogenous hypoechoic fluid. Based on the anamnesis and clinical examination, a tentative diagnosis of perineal herniation was made. Considering the deteriorating clinical condition of the cow and the possible risk of dystocia, the viable calf was delivered by Caesarean section. The cow recovered with a reducible hernial sac, which was decided not to correct surgically due to its large size. After 7 days, the cow showed no further complications and was discharged. In conclusion, although rare, a perineal hernia involving the uterus should be considered in the differential diagnosis of perineal swellings in pregnant cows.

195 Effect of selection for growth and maternal influence on crossbred Angus heifer development

Abstract This multiyear experiment was designed to determine the effects of sire yearling weight (YW) and maternal influence (MILK) expected progeny differences (EPD) on production and fertility of beef replacement heifers. Sires were classified as moderate (< 50th percentile) or high for YW EPD (122 ± 29; from 79 to 172) and as low (< 50th percentile) or high for MILK EPD (27 ± 8; from 5 to 40). Fall-born (n = 214) and spring-born (n = 207) heifers were enrolled in the study. Birth weight (BW), weaning weight (WW), and YW of the heifers were measured. In addition, reproductive tract score (RTS), dry matter intake (DMI), and average daily gain (ADG) while consuming an unprocessed grass hay diet were determined in a subsample of enrolled heifers. Neogen Igenity Beef scores (NIBS) were also run on this subset. Pregnancy rate and conception rate at fixed timed artificial insemination (FTAI) were also determined. Adjusted BW, WW and YW and RTS were analyzed using the GLIMMIX procedure of SAS (9.4, SAS Institute Inc., Cary, NC), with YW and MILK EPD as fixed effects and year of birth as random effect. Effects of sire YW and MILK classification on the likelihood of pregnancy and successful FTAI were also analyzed using the GLIMMIX procedure of SAS. Pearson correlation coefficients between independent and dependent variables were obtained using the CORR procedure of SAS. Sire MILK EPD had no effect (P ≥ 0.13) on the body weight of fall- or spring-born heifers. However, fall-born heifers were 0.12 kg and 0.34 kg heavier (P = 0.06 and 0.001, respectively) per unit increase in sire YW EPD at weaning and yearling time, respectively. There was no effect of sire YW EPD on fall-born heifer DMI as percentage of body weight (DMI % BOW; P = 0.74) nor ADG (P = 0.90) while consuming the low-energy diet. Spring-born heifers had significantly greater (all, P ≤ 0.001) adjusted BW, WW, and YW (0.02, 0.23 and 0.37 kg per unit increase in sire YW EPD, respectively. Reproductive tract score was strong and negatively correlated (P ≤ 0.001) with DMI % BOW. Heifer YW NIBS were moderate and positively correlated (P < 0.001) with ADG. There was a tendency (P = 0.09) for a weak and negative correlation between residual feed intake genetic scores and DMI % BOW. Sire genetic merit for yearling growth was transmitted to replacement heifers. However, neither ADG, nor unprocessed forage DMI % BOW was influenced by genetic potential for growth during this study. Further research is needed to assess the benefits of using genomic profile of heifers for maternal, performance and carcass traits, alongside sire EPDs, when selecting and developing beef replacement heifers.

Effect of enhanced plane of nutrition in early life on the transcriptome and proteome of the anterior pituitary gland in Angus heifer calves

BackgroundEnhanced nutrition during the early calfhood period has been shown to lead to earlier pubertal development in heifer calves. This is of interest as earlier pubertal onset can subsequently facilitate earlier calving which can economically benefit production systems. Reproductive development in heifers is regulated by the hypothalamic-pituitary-ovarian signalling pathway. In particular the anterior pituitary gland is central to reproductive development, through the dynamics of gonadotropic pulsatility. However, despite clear knowledge of the influence of enhanced dietary intake on subsequent reproductive development, the molecular control governing this response in the pituitary gland within the hypothalamic-pituitary-ovarian signalling axis in heifer calves is not fully understood. The objective of this study was to examine the effect of an enhanced plane of nutrition during early life on the anterior pituitary gland of heifer calves through both transcriptomic and proteomic analyses. Between 3 and 21 weeks of age, heifer calves were offered either a high (HI, n = 14) or moderate (MOD, n = 14) plane of nutrition, designed to elicit target growth rates of 1.2 and 0.5 kg/d for HI and MOD groups, respectively. All calves were euthanised at 21 weeks of age and anterior pituitary tissue harvested for subsequent use in global transcriptomic and proteomic analyses.ResultsAverage daily gain was affected by diet (P < 0.001) and was 1.18 and 0.50 kg/day, for HI and MOD calves, respectively. RNAseq analysis resulted in the identification of 195 differentially expressed genes (Padj<0.05; fold change > 1.5), with 277 proteins identified as differentially abundant (Padj<0.05; fold change > 1.5) between contrasting dietary treatment groups. Biochemical pathway analysis of differentially affected genes and proteins revealed an enrichment for both growth hormone and GnRH signalling pathways (Padj.<0.05). Additionally, pathway analysis predicted an effect of enhanced dietary intake on endocrine function within the anterior pituitary gland as well as on reproductive system development and function (Padj.<0.05).ConclusionsResults from this study show that an enhanced dietary intake during early calfhood affected the molecular control of the anterior pituitary gland in heifer calves in early life.

PSII-8 Analysis of maternal influence on phenotypic ultrasound measurements of weaned Angus calves

Abstract Ultrasound carcass data can be used to accurately estimate the body composition of beef cattle in comparison with a body composition score. Literature regarding the analysis of phenotypic carcass data has focused predominately on yearling or mature cattle with limited measurements on weaned calves. Therefore, the influence of the milking ability of the dam on body composition traits measured via carcass ultrasound is unknown. The objective of this study was to estimate correlations between the maternal influence of the dam on the phenotypic ultrasound measurements of the calf. To quantify maternal influence, the expected progeny difference (EPD) for milk (MILK) of the dam was correlated to three ultrasound measurements of the calf: backfat thickness (BFAT), ribeye area (REA), and intramuscular fat (IMF). Ultrasound measurements were collected 1 wk after weaning on 104 purebred Angus heifer calves from the Iowa State University McNay Memorial Research and Demonstration Farm located outside Chariton, Iowa. The average age and body weight for heifers were 187 d and 195 kg, respectively. The milk EPD of the dam was correlated to the ultrasound measurements taken on the calves. For each trait, Pearson’s correlations were calculated between the ultrasound traits of the calf to the dam’s milk EPD using R Statistical Software version 4.3.1. A small positive correlation was identified between MILK and REA (r = 0.28, P = 0.004). This suggests a weak phenotypic relationship between MILK and REA for weaned heifers. The correlation between MILK to BFAT and IMF was 0.10 (P = 0.318) and -0.05 (P = 0.619), respectively. These correlations were not significantly different from zero. This suggests the potential for milk production of the dam has little association with BFAT and IMF for weaned heifers. Although further research is needed, the results from this study indicate little to no relationship between milk EPD of the dam on ultrasound measures of the calf for BFAT, REA, and IMF.

PSI-A-8 The Effect of Rumen Capacity Manipulation on Dry Matter Intake on Diets Differing for Processing Level

Abstract Rumen fill is a driving force behind intake in ruminant animals consuming unprocessed forage. The objective of this study was to determine the effect of rumen available capacity on feed intake of diets processed to different levels. To evaluate the effect of rumen capacity, intake of a fistulated Angus heifer (716 kg, 4 yr) was evaluated at full rumen capacity and one-half capacity on the same diet processed to three different fiber lengths: unprocessed, long-stemmed hay, processed in a bale buster to fiber lengths of 15 cm, and ground hay with fiber lengths of 3 cm. The heifer was housed in a drylot pen with ad libitum access to water and consumed the diet out of a SmartFeed individual intake unit. The intake unit was filled twice a day at 0700 and 1700 h. The heifer consumed each diet for a period of 10 days. The first 5 days of each period the heifer consumed the diet at full rumen capacity, for the remaining 5 days of each period, two weather balloons were inserted into the rumen and distended with water to reduce rumen capacity to 50% capacity. As expected, the heifer consumed more of the diet when the diet had some form of further processing (P &amp;lt; 0.05). Rumen capacity affected intake in a linear manner related to the level of processing in the diet (P &amp;lt; 0.05).

Evaluation of Zoetis GeneMax Advantage genomic predictions in commercial Bos taurus Angus cattle

The GeneMax (GMX) Advantage test, developed by Zoetis, uses approximately 50,000 single nucleotide polymorphisms (SNP) to predict the genomic potential of a commercial Angus heifer. Genetic predictions are provided for Calving Ease Maternal, Weaning Weight, Heifer Pregnancy, Milk, Mature Weight, Dry Matter Intake, Carcass Weight, Marbling, Yield, and three economic selection indices. Test results can inform selection and culling decisions made by commercial beef cattle producers. To measure the accuracy of the trait predictions, data from commercial Angus females and their progeny at the University of Missouri Thompson Research Center were utilized to analyze weaning weight, milk, marbling, fat, ribeye area, and carcass weight. Progeny phenotypic data were matched to the respective dam, then the cow's genomic predictions were compared to the calf's age-adjusted phenotypes using correlation and linear model effect sizes. All tested GeneMax scores of the dam were significantly correlated with and predicted calf performance. Our predicted effect sizes, except for fat thickness, were similar to those reported by Zoetis. In conclusion, the GeneMax Advantage test accurately ranks animals based on their genetic merit and is an effective selection tool in commercial cowherds.

PSIII-7 Late-Breaking: Improving Heifer Development Programs Using Precision Supplementation

Abstract Improving individual animal efficiency is important for livestock producers to run financially sustainable operations. Developing heifers to replace a cow in the herd is expensive and reducing costs during the growing and reproductive phases is critical to increase profitability. Precision livestock management technologies can help reduce feed waste and optimize individual animal intake on extensive rangeland systems. Precision supplementation for heifer development programs aims to provide proper nutrition management and develop heifers to meet target body weight without over or under conditioning. With conventional feeding methods, animals are able to over consume feed and may be overdeveloped. Therefore, the objective of our study was to compare differences in yearling heifer performance between conventional and precision supplementation on winter rangeland pastures. The study was conducted at the South Dakota State University Cottonwood Field Station, located near Philip, SD. Angus heifer calves (Bos taurus, n = 60) born in the spring of 2021were utilized for the project. Following fall weaning, initial weight was used to randomly assign heifers to one of two treatments: control (n = 30) or precision (n = 30). Treatment groups were separated into different pastures to graze dormant native range from November to June and were rotated monthly to reduce pasture influence. Both groups were offered 2.27 kg/hd/d dried distillers grain pellets; the control group was bunk fed, allowing for normal variation in consumption and the precision group was fed individually using the Super SmartFeed Producer. Individual daily BW was measured using SmartScale technology and used to calculate daily rate of gain. Heifers were supplemented to reach 60% of their mature body weight (MBW; 635 kg) at time of breeding. Heifers were bred in June using estrus synchronization with fixed time artificial insemination. Statistical analysis was conducted in Program R, which included an ANOVA to evaluate the differences in ADG between the control and precision treatments. Our results indicated a significant difference in average daily gain between the control (P &amp;lt; 0.05), mean ADG of 1.94 and 1.76 lb/d, respectively. Further, the control group utilized 5,600 lb more feed compared to the precision group. The number of heifers that achieved estrous was similar for both control (27) and precision groups (25) based on visual qualitative assessment of heat detection patches. At completion of the winter grazing season, the control group was developed to 64.9% MBW with an average weight of 909.37 lb and the precision group reached 62.2% MBW with an average weight of 870.37 lb. Successful implementation of precision supplementation has the potential to develop more uniform heifers at breeding, reduce intake variation, and reduce supplement overconsumption.

Enhancing early life nutrition alters the hepatic transcriptome of Angus × Holstein-Friesian heifer calves

Early life nutrition has a major influence on subsequent lifetime performance in cattle. The aim of this experiment was to investigate the effect of plane of nutrition from 3 to 21 weeks of age on the liver transcriptome. Holstein-Friesian × Angus heifer calves with a mean (±SD) age and BW of 19 (±5) days and 51.2 (±7.8) kg, respectively, were assigned to either a high-energy diet to support a mean average daily gain (ADG) of 1.2 kg/day (HI; n = 15) or a moderate diet (MOD; n = 15) to support a mean ADG of 0.5 kg/day. At 145 ± 3 days of age, all calves were euthanised, liver tissue samples collected and flash-frozen in liquid nitrogen. Following RNA sequence analysis, the total number of differentially expressed genes (DEGs) (at false discovery rate (FDR) > 0.05) was 537; 308 upregulated and 229 downregulated in HI compared to MOD. The number of DEGs mapped to IPA (at FDR > 0.05) was 460; 264 upregulated and 196 downregulated. There was greater expression of genes associated with cellular development and metabolism in heifers on the HI compared to the MOD diet. The genes (fold change) of the somatotrophic axis; IGF1 (3.7), IGFALS (2.6) and GHR (1.5) were upregulated in the HI compared to MOD diet. The cytokine receptor genes, IL17RB (1.7) and IL20RA (3.3), were upregulated in the HI heifers, which were detected in a network interacting with metabolically regulated genes. The potential enhanced cell-to-cell communication evident from DEGs would increase the calves’ ability to combat health challenges. The findings of this study indicate that enhancing the early life plane of nutrition in heifer calves results in the upregulation of genes that are associated with increased metabolic activity and thus metabolic capacity. Moreover, the interaction between metabolic and immune communication genes indicates that enhanced nutrition has the potential to improve the immune response in the liver which will play a central role in ensuring optimal lifetime performance.

Intranasal oxytocin treatment on the day of weaning does not decrease walking behavior or improve plasma metabolites in beef calves placed on pasture

The purpose of this study was to evaluate the effect of intranasal oxytocin administered at abrupt weaning on weaning behaviors such as walking distance and time devoted to walking, calf body weight, and plasma non-esterified fatty acids (NEFAs), β-hydroxybutyrate (β-HB), and cortisol. Twenty Simmental × Angus heifer calves were randomly assigned to one of two treatments: intranasal oxytocin (OXT; n = 10) or intranasal saline (CON; n = 10). All calves were given the respective intranasal treatment on the day of weaning (day 0) and then placed on pasture together. Calves were weighed and a blood sample was obtained on days 0, 1, 7, and 14 postweaning. Blood samples were subsequently used to quantify plasma NEFA, β-HB, and cortisol concentrations. All calves in both treatment groups were fitted with an individual global positioning system that recorded calf location every 10 s for a 16-h period on days 0, 7, and 14 to quantify and evaluate walking behaviors. There was no treatment × day effect for distance walked (P = 0.82), walking time (P = 0.80), non-walking time (P = 0.88), area utilization index (P = 0.84), calf body weight (P = 0.82), average daily gain (P = 0.54), NEFA (P = 0.22), or cortisol concentrations (P = 0.32). There was a tendency for a treatment × day effect observed for average walking speed (P = 0.09) and β-HB (P = 0.10), such that calves in the CON treatment tended to have lesser average walking speeds on day 14 and tended to have greater β-HB concentration after weaning. There was a treatment effect (P = 0.02) for NEFA concentrations, with the CON calves having a greater plasma NEFA concentration throughout the study compared with OXT calves. These data imply that OXT calves may have had differing metabolic responses immediately after weaning that could have altered the mobilization of NEFA, but this change was not substantial enough to impact body weights or walking behaviors.

Cerebrocortical necrosis causes multiple deaths in Scottish ewes and lambs.

Cerebrocortical necrosis causes multiple deaths in Scottish ewes and lambs.

Effect of plane of nutrition in early life on the transcriptome of visceral adipose tissue in Angus heifer calves

Adipose tissue represents not only an important energy storage tissue but also a major endocrine organ within the body, influencing many biochemical systems including metabolic status, immune function and energy homeostasis. The objective of this study was to evaluate the effect of an enhanced dietary intake during the early calfhood period on the transcriptome of visceral adipose tissue. Artificially reared Angus × Holstein–Friesian heifer calves were offered either a high (HI, n = 15) or moderate (MOD, n = 15) plane of nutrition from 3 to 21 weeks of life. At 21 weeks of age all calves were euthanized, visceral adipose harvested and samples subsequently subjected to mRNA sequencing. Plane of nutrition resulted in the differential expression of 1214 genes within visceral adipose tissue (adj. p < 0.05; fold change > 1.5). Differentially expressed genes were involved in processes related to metabolism and energy production. Biochemical pathways including Sirtuin signalling (adj. p < 0.0001) and the adipogenesis pathways (adj. p = 0.009) were also significantly enriched, indicating greater metabolic processing and adipogenesis in the calves on the high plane of nutrition. Results from this study identify novel genes regulating the molecular response of visceral adipose tissue to an improved plane of nutrition during early calfhood.

The effect of a social facilitator cow on the distance walked and time spent walking by abruptly weaned beef calves

Context Separation of a calf from its dam at weaning can cause stress behaviours such as excessive walking and vocalising. These behaviours combined with poor dry matter and water intakes during weaning can cause bodyweight loss in calves. We questioned whether adding a social facilitator cow to pens of calves weaned on pasture would decrease calf walking behaviours and prevent a loss in bodyweight. Aims We tested the hypothesis that a social facilitator (SF) cow at weaning would reduce the walking behaviours of calves and increase calf bodyweight. Methods Eighty Simmental × Angus heifer calves were allocated to four replications. In each replication, 20 heifer calves were randomly assigned to either the SF (n = 10) treatment in which calves were abruptly weaned and placed on pasture with a SF cow on the day of weaning (day 0), or to the control (CON, n = 10) treatment in which calves were abruptly weaned and placed on pasture without a SF cow. All calves had their bodyweight recorded and were blood sampled on Days 0, 1, 7, and 14 for non-esterified fatty acids and β-hydroxybutyrate concentration. To quantify and evaluate walking behaviours, all calves were fitted with an individual global positioning system collar that recorded calf location every 10 s for a 24-h period on Days 0, 7, and 14. Key results There was no effect for time spent walking (P = 0.07) or distance walked (P = 0.08), although the SF calves spent numerically less time walking and walked shorter distances on the day of weaning compared with the CON calves. There were no differences observed for calf bodyweight or average daily gain. Conclusion The results of this study indicate that the addition of a SF animal at weaning does not affect the distance walked on the day of weaning or the time calves devote to walking. Implications It is unlikely that a SF cow will decrease the distance and time spent walking by calves enough to improve calf bodyweight.

PSI-31 Retrospective analysis of growth performance and carcass ultrasound data of yearling bulls enrolled at the Cal Poly Bull Test

Abstract Since 1956, the Cal Poly Bull Test has evaluated performance of yearling bulls in a multi-breed contemporary group in the western United States. The main objectives of this study were to evaluate the consistency of the relationship between growth and ultrasound traits and between the number of bulls selling and sale price over a 19-year period from 2001–2019. Out of 3,712 bulls, a total of 2,503 Angus and 453 Hereford bulls were used in the analyses using SAS. Bulls were sold in the following pre-determined breed categories; Angus Heifer Bulls, Multi-Trait Angus Bulls, Growth Angus Bulls, and Hereford Bulls. The breed × year interaction significantly (P &amp;lt; 0.01) affected sale price, scrotal circumference (SC), ultrasound ribeye area (UREA), ultrasound intramuscular fat percentage (UIMF), end weight, and average daily gain (ADG). Overall, Hereford bulls had significantly (P &amp;lt; 0.0001) lower ADG than Angus bulls. A positive relationship between ADG and UREA (P &amp;lt; 0.0001; r2 = 0.10) and between UREA and SC (P &amp;lt; 0.0001; r2 = 0.05) was observed. A significant, positive relationship (P &amp;lt; 0.01; r2 = 0.24) between end weight and REA was also exhibited. A significant breed × year interaction (P &amp;lt; 0.01) was observed for sale price, wherein Angus heifer bulls consistently sold for the highest price. Additionally, sale price analyses indicated a moderate, negative relationship (P = 0.02; r2 = -0.584) between number of animals entered in the sale and price. Consistently, Angus bulls had higher (P &amp;lt; 0.0001) sale prices. Sales with higher bull numbers were those with the lowest average prices. The year and breed category explained 31 and 22.5 % of the variance in the price, respectively. Growth performance and sale price may have a biological or genetic component as indicated by breed differences consistently over the 19-year period.

307 A social facilitator can reduce calf walking behavior at weaning

Abstract Common industry practice is to wean beef calves prior to natural weaning with the objectives of improving cow body weight and preparing calves for the subsequent receiving, growing, and finishing phases of production. Discontinuing the cow-calf social and nutritional bond before natural weaning, however, causes atypical walking and vocalizing behaviors by calves that are detrimental to calf growth and health. A proposed alternative weaning method is the addition of a social facilitator cow at weaning to reduce calf stress. Utilizing global positioning system (GPS) technology, we were able to determine total distance walked, total time devoted to walking, and area of the pasture utilized by the calf. Thus, the objective of the present study was to evaluate the effects of a social facilitator on calf growth during weaning and more specifically, walking behaviors, utilizing a Garmin® product. Angus x Simmental heifer calves (n = 80) were used in this study, and in all four replications calves were randomly allotted to each treatment group (n = 10), social facilitator (SF) or control (CON) on the day of weaning (day 0). Calves in the SF group were placed on pasture at weaning with a social facilitator, and CON calves were placed in a similar sized pasture without a social facilitator. All calves were allocated their own GPS tracking device on days 0 (weaning), 7, and 14 for a full 24 hours before removal. Data were analyzed as a randomized complete block design with repeated measurements (SAS 9.4). Placing calves with a social facilitator decreased the distance walked (P = 0.001), and the amount of time calves devoted to walking (P = 0.001). Placing a social facilitator with calves at weaning, therefore, has an effect on walking distance and amount of time calves devote to walking.

Can the antral follicular count modulate the gene expression of bovine oviducts in Aberdeen Angus and Nelore heifers?

The number of visible ovarian antral follicles (antral follicle count—AFC) is repeatable in bovine individuals, but highly variable between animals, and with differences between Bos taurus and Bos indicus breeds. Several studies have tried to determine the correlation between AFC and increased fertility in cattle. While the impacts of AFC on embryo production, hormonal levels, and pregnancy rates have been described, the molecular effects of AFC on bovine oviducts have not yet been investigated. Here, the aim was to investigate the impact of breeds, such as Aberdeen Angus and Nelore heifer with high or low AFC, on abundance of transcripts and protein related to oviductal transport, sperm reservoir formation, monospermy control, and gamete interaction in the oviducts. In summary, the ovulation side was the major factor that affected transcript abundance on bovine oviducts. However, a discreet effect among AFC and cattle breeds was also observed. Based on this, we concluded and reinforced here that differential microenvironments between ipsilateral and contralateral oviducts have a major effect on modulating the transcripts related to oviductal transport, sperm reservoir formation, monospermy control, and gamete interaction. However, we cannot exclude that there is minimal effect of AFC or breed on regulation of some genes (such as AGTR1, ACE1, FUCA1, and VEGFA) in bovine oviducts.

The Effects of Feeding Reduced-Lignin Alfalfa on Growing Beef Cattle Performance: a Preliminary Study

Gene suppression techniques down-regulating specific lignin biosynthesis pathway enzymes have permitted the development of an alfalfa variety with an altered lignin content and composition known as HarvXtra. This study was designed to compare the difference in forage nutrient quality between reduced-lignin alfalfa hay (variety HX-4114) and conventional alfalfa hay (variety WL336HQRR), and to evaluate Angus heifer performance when fed treatments of HX-4114 and WL336HQRR. Twenty-four Angus heifers (8 months of age; initial BW = 270 ± 21 kg) were selected to participate in an 84-day alfalfa hay feeding trial. Their performance was evaluated based on changes in body weight (BW), average daily gain (ADG), dry matter intake (DMI), and gain to feed ratio (G:F). Additionally, in situ dry matter disappearance was tested using four ruminally cannulated Hereford cows. Hay samples were collected and used to determine forage nutrient quality, leaf count, and leaf-to-stem ratio. Significance was set at P ≤ 0.05. There were no differences (P ³ 0.05) in forage nutrient quality between alfalfa treatments. Means did not differ by treatment for leaf count (P = 0.06), but leaf-to-stem ratio was higher (P = 0.04) for HX-4114 than WL336HQRR (1.67 vs. 1.17, respectively). There were no treatment or treatment by day interactions for BW, ADG, DMI, G:F, or in situ dry matter disappearance. Additionally, animal performance did not differ for growing Angus heifers consuming HX-4114 and WL336HQRR alfalfa hay. More research is warranted to determine the value of utilizing different genotypes of reduced-lignin alfalfa and their impact on the U.S beef industry.

Effect of measurement duration in respiration chambers on methane traits of beef cattle

Records on 1043 young Angus heifer and bull progeny from 73 sires, measured for methane production in respiration chambers, were used to evaluate the accuracy of a 1-day measurement relative to 2-day measurement duration. The traits assessed were dry matter intake (DMI, kg/day), methane-production rate (MPR, g/day), methane yield (MY, MPR per unit DMI) and four residual methane (RMP, g/day) traits. The RMP traits were computed as actual MPR minus expected MPR, where the expected MPR were calculated from three widely used equations. The expected MPR for the fourth RMP trait was computed by regressing MPR on DMI, using the data from the study. Variance components, heritability, phenotypic and genetic correlations, and the efficiency of selection using 1-day compared with 2-day measurement were used as assessment criteria. The environmental variance for the 2-day measurement was slightly lower than that of the 1-day measurement for all the traits studied, indicating that the addition of an extra day of data was effective in reducing the amount of unexplained variation in each trait. However, these minor reductions did not have a major impact on accuracy; hence, very high phenotypic (rp of 0.91–0.99) and genetic (rg of 0.99 for each trait) correlations were obtained between the two measurement durations. The very high genetic correlation between the two durations of measurement indicated that, at the genetic level, the 1-day duration is measuring the same trait as the 2-day measurement duration. Any enteric-methane emission-abatement strategy that seeks to reduce MPR per se, may have a detrimental impact on ruminant productivity through a correlated reduction in feed intake; hence, MY and the RMP traits are likely to be the traits of interest for genetic improvement. Efficiency of selection for MY and the RMP traits ranged from 0.96 to 0.99, which implies that there would be less than 5% loss in efficiency by adopting a 1-day relative to a 2-day methane-measurement duration. While the throughput of the respiration-chamber facility can be increased by adopting a 1-day measurement duration, additional resources, such as holding pens, would be required to take advantage of the extra day.

Repeatability of methane emission measurements in Australian beef cattle

Records on 175 young Angus heifer and bull progeny from 46 sires, measured for methane production in respiration chambers, were used to evaluate the repeatability of methane measurement over short- and long-term periods. The traits assessed were dry matter intake (DMI), methane production rate (MPR), methane yield (MPR per unit DMI), and four residual methane (RMP) traits. The RMP traits were computed as actual MPR minus expected MPR, where the expected MPR for the first three RMP traits were calculated from three different published and widely used equations. The expected MPR for the fourth was computed by regressing MPR on DMI, using the data from the study. Animals underwent an initial (first) methane measurement test for 48 h, and one repeat methane measurement test up to 450 days after the first test. Repeat tests were classified into four different time periods: tested across consecutive days; re-tested within 60 days of first test; re-tested 61–120 days after first test; and re-tested 121–450 days after first test. Repeatabilities were calculated for all traits across all time periods, and phenotypic correlations for the same trait measured over time were obtained from bivariate analyses. Methane traits from tests conducted over consecutive days were highly repeatable (0.75–0.94) and highly phenotypically correlated (0.85–0.95). Repeatabilities from tests conducted within 60 days of the first test were moderate to high (0.59–0.91), whereas phenotypic correlations were, in general, moderate (0.30–0.44), with the exception of MPR (0.78). Results for both longer-term time periods (61–120 days and 121–450 days after the first test) were very similar, with low estimates of repeatabilities (0.16–0.27) and phenotypic correlations (0.12–0.27). Correlations between sire progeny means from the first and repeat methane test were moderate (0.46–0.77) for all traits except RMPR (0.19). Results from this study indicate that methane traits from tests conducted either on consecutive days or within a short-term time frame afterward (~60 days) are highly repeatable and highly phenotypically correlated. However, methane tests conducted over longer-term time frames are substantially, but consistently, less repeatable and are lowly phenotypically correlated, which indicates that multiple measures may be required to accurately record methane traits over the life time of an animal.

Analysing quantitative parent‐of‐origin effects with examples from ultrasonic measures of body composition In Australian beef cattle

Parent-of-origin effects arise when an individual's genes are modified during gametogenesis. Commonly known as imprinting, affected genes may be completely, or partially, suppressed. Individual loci in mice, human and sheep are known to be imprinted, and the quantitative effects of imprinted loci have been found for many carcass traits in cattle and pigs. Differentiating between five types of loci - direct additive loci and partially and completely imprinted loci by sires and dams - is not possible as their effects are confounded such that only three of seven parameters can be estimated. An analysis of Australian Hereford and Angus heifers and bulls for four ultrasonic measures of body composition - eye muscle area, rib fat, rump fat and intramuscular fat per cent - found parent-of-origin effects for both parents in most trait-gender data sets and that they were an average of 28% of the total genetic variance. No parent-of-origin effects were found for Hereford bull intramuscular fat per cent and the maternal parent-of-origin effects were not significant for Angus Heifer eye muscle area.

Isolation of Vibrio Cholerae from the Brain of a Feedlot Heifer with Meningoencephalitis

A 700-pound, 9-month-old Angus heifer from a feedlot presented with acute neurologic signs, characterized by circling, posterior weakness, and nonresponsiveness, followed by death. Histologically, the frontal lobe and the thalamus contained multiple foci of liquefaction that contained numerous degenerative neutrophils and foamy macrophages. Some of these foci were centered on blood vessels that contained fibrin thrombi and exhibited varying degrees of fibrinoid necrosis of the vessel wall. There was adjacent axonal degeneration and neuronal necrosis characterized by pronounced cytoplasmic eosinophilia, peripheralization of the nuclei, and loss of Nissl substance. Aerobic culture of the brain yielded moderate growth of Vibrio species, which was determined to be Vibrio cholerae by polymerase chain reaction analysis of a 438-base pair fragment of the 16 S ribosomal RNA gene. V. cholerae are motile, gram-negative, curved rod-shaped bacteria. Some strains of V. cholerae are important food- and water-borne bacterial pathogens that produce an often fatal diarrhea in humans. This is the first known case report of V. cholerae meningoencephalitis and cerebral abscessation in a bovine.