Ranking Animals Research Articles

Comparison of greenhouse gas emissions from sheep measured using both respiration and portable accumulation chambers

Methane (CH4) is a potent gas produced by ruminants, and new measurement techniques are required to generate large datasets suitable for genetic analysis. One such technique are portable accumulation chambers (PAC), a short-term sampling method. The objectives of the current study were to explore the relationship between CH4 and carbon dioxide (CO2) output measured using both PAC and respiration chambers (RC) in growing lambs, and separately investigate the relationship among CH4, CO2 and measured ad libitum DM intake (DMI). Methane, CO2 and DMI were measured on 30 Suffolk and 30 Texel ewe lambs (age 253 ± 12 days) using the RC and PAC sequentially. The experiment was conducted over a 14-day period, with DMI measured from days 1 to 14; measurements in RC were conducted from days 10 to 12, while measurements in PAC were taken twice, the day immediately prior to the lambs entering the RC (day 9; PAC Pre-RC) and on the day lambs exited the RC (day 13; PAC Post-RC). Greater CH4 and CO2 output was measured in the RC than in the PAC (P < 0.01); similarly mean CH4 yield was greater when measured in the RC (15.39 ± 0.452 g CH4/kg DMI) compared to PAC (8.01 ± 0.767 g CH4/kg DMI). A moderate correlation of 0.37 was found between CH4 output measured in PAC Pre-RC and the RC, the corresponding regression coefficient of CH4 output measured in the RC regressed on CH4 output measured in PAC Pre-RC was close to unity (0.74; SE 0.224). The variance of CH4 and CO2 output within the measurement technique did not differ from each other (P > 0.05). Moderate to strong correlations were found between CH4 and CO2 per kg of live weight and CH4 and CO2 yield. Results from this study highlight the suitability of PAC as a ranking tool to rank animals based on their gaseous output when compared to the RC. However, repeated measurements separated by several days may be beneficial if precise rankings are required. Given the close to unity regression coefficient of CH4 output measured in the RC regressed on CH4 output measured in PAC Pre-RC suggests that PAC could also be potentially used to estimate absolute CH4 output; however, further research is required to substantiate this claim. When DMI is unknown, CH4 and CO2 per kg of live weight are a suitable alternative to the measurement of CH4 and CO2 yield.

Validation of the methane production measurement accuracy and ranking capacity of portable accumulation chambers for use with small ruminants

Using portable accumulation chambers (PAC) is an attractive approach to recording methane (CH4) production of small ruminants. Mass flow controllers (MFC), for their part, are an effective way of validating PAC measurements, as they allow to simulate methane production rates freely of extraneous factors. The present study describes a series of tests carried out to evaluate the accuracy and precision of methane mass recordings of eight PAC against known CH4 masses released by a MFC. Across the tested range, the PAC were able to recover between 67.6 and 74.5% of the true CH4 released. No significant differences were detected between the different PAC, but a statistically significant linear shift was detected over the mass range. Therefore, PAC as currently used are not well suited for applications looking at absolute production levels requiring high absolute accuracy. If recovery tests are conducted regularly across the measurement range, a calibration factor could be generated to correct for the inaccuracy. These PAC were however well suited for investigating relative differences between animals, e.g. ranking animals to compare differences in CH4 production between breeds. The methane recordings made by these chambers were highly precise, with low coefficients of variation between replicates (0.0–2.4%) and high repeatability (>0.99). Furthermore, the correlation between released and recorded CH4 masses was very strong and positive (R > 0.99). Overall, the mass recovery test presented here provides a feasible method for harmonizing methane monitoring procedures using PAC between research groups, thereby improving joint efforts aimed at mitigating greenhouse gas production in small ruminants.

Selection indexes to optimise genetic and economic progress in Colombian Blanco Orejinegro cattle

The use of selection indexes optimises genetic and economic gains in a population. The objective of this study was to propose and compare selection indexes built with economic and statistical methodologies in Colombian Creole Blanco Orejinegro breed. Genetic, phenotypic and economic information of the breed were used to design and test the selection indexes. The weights of each selection criteria (weight at 24 months of age, age at first calving, calving interval) were estimated using phenotypic variances, eigenvectors from a principal component analysis and economic values obtained through a deterministic bio-economic model. The selection criteria with the highest weight was weight at 24 months of age, with values of 0.56 and 0.034 USD using eigenvectors and phenotypic variance, respectively. The calving interval had the highest weight using the bio-economic model, with a value of -1.3 USD. The greatest profit due to genetic selection was obtained using the economic values as weights, which increased the average expected profit to a value of 18.76 USD/cow/year. The selection indexes calculated from phenotypic and eigenvectors do not rank animals similarly to the economic selection index. It could generate less genetic and economic progress in the national selection programme for the Blanco Orejinegro breed.

Adaptive immune response ranking is associated with reproductive phenotypes in grazing dairy cows divergent in genetic merit for fertility traits

A strong adaptive immune response has been reported to have positive effects on fertility; therefore, we investigated antibody- and cell-mediated adaptive immune responses (AMIR and CMIR, respectively) and their associations with reproductive phenotypes using a population of animals that differed in their estimated genetic merit for fertility traits (fertility breeding value; FertBV). Holstein-Friesian heifers (n = 528) grazed on pasture in 4 herds based on age. These herds included 277 heifers of positive (POS) FertBV and 251 of negative (NEG) FertBV. The adaptive immune response (IR) was evaluated before puberty at 7.5 mo of age and used to rank animals as high, average, or low for AMIR, CMIR, and overall IR (combined CMIR and AMIR). The animals were studied from 12 wk of age through to the end of their second lactation to measure growth, puberty, and timing and success of fertility phenotypes, including those related to ovulation and pregnancy. Initial analysis indicated no difference in fertility outcomes between cows ranked as high or average for AMIR (n = 55, n = 407, respectively), CMIR (n = 87, n = 354, respectively), and IR (n = 29, n = 470, respectively), so these groups were pooled as HiAv-IR. Proportions of heifers of POS FertBV were similar within HiAv and low categories across AMIR (0.52 and 0.58, respectively), CMIR (0.51 and 0.59, respectively), and IR (0.53 and 0.48, respectively). Heifers with HiAv-IR had a greater average daily weight gain from 13 to 52 wk of age (661 g, 95% confidence interval 652, 669 vs. 619 g, 95% confidence interval 591, 647) and tended to be younger at puberty (371 d, 95% confidence interval 366, 377 vs. 385 d, 95% confidence interval 369, 401) than low-IR heifers. Low-CMIR cows of a NEG FertBV had a >40 d longer calving to first ovulation interval during their first lactation compared with HiAv-CMIR NEG FertBV cows. Low-CMIR cows also had decreased pregnancy rates at both 3 wk (25% ± 7% vs. 42% ± 3%; least squares means ± standard error) and 6 wk (33% ± 7% vs. 54% ± 3%; least squares means ± standard error) into the seasonal breeding period during their first lactation, compared with HiAv-CMIR cows. In summary, although the number of POS and NEG FertBV cows was similar in each immune group; interaction effects between FertBV and immune ranking on reproductive phenotypes are evident when cows were ranked by the overall IR. There were also associations between dairy cows' CMIR ranking and ability to return to estrus and become pregnant early in the breeding period, which will have benefits in seasonal breeding systems.

Measuring Livestock CH4 Emissions with the Laser Methane Detector: A Review

The handheld, portable laser methane detector (LMD) was developed to detect gas leaks in industry from a safe distance. Since 2009, it has also been used to measure the methane (CH4) concentration in the breath of cattle, sheep, and goats to quantify their CH4 emissions. As there is no consensus on a uniform measurement and data-analysis protocol with the LMD, this article discusses important aspects of the measurement, the data analysis, and the applications of the LMD based on the literature. These aspects, such as the distance to the animal or the activity of the animals, should be fixed for all measurements of an experiment, and if this is not possible, they should at least be documented and considered as fixed effects in the statistical analysis. Important steps in data processing are thorough quality control and reduction in records to a single point measurement or “phenotype” for later analysis. The LMD can be used to rank animals according to their CH4 breath concentration and to compare average CH4 production at the group level. This makes it suitable for genetic and nutritional studies and for characterising different breeds and husbandry systems. The limitations are the lower accuracy compared to other methods, as only CH4 concentration and not flux can be measured, and the high amount of work required for the measurement. However, due to its flexibility and non-invasiveness, the LMD can be an alternative in environments where other methods are not suitable or a complement to other methods. It would improve the applicability of the LMD method if there were a common protocol for measurement and data analysis developed jointly by a group of researchers.

Effect of divergence in residual methane emissions on feed intake and efficiency, growth and carcass performance, and indices of rumen fermentation and methane emissions in finishing beef cattle.

Residual expressions of enteric emissions favor a more equitable identification of an animal’s methanogenic potential compared with traditional measures of enteric emissions. The objective of this study was to investigate the effect of divergently ranking beef cattle for residual methane emissions (RME) on animal productivity, enteric emissions, and rumen fermentation. Dry matter intake (DMI), growth, feed efficiency, carcass output, and enteric emissions (GreenFeed emissions monitoring system) were recorded on 294 crossbred beef cattle (steers = 135 and heifers = 159; mean age 441 d (SD = 49); initial body weight (BW) of 476 kg (SD = 67)) at the Irish national beef cattle performance test center. Animals were offered a total mixed ration (77% concentrate and 23% forage; 12.6 MJ ME/kg of DM and 12% CP) ad libitum with emissions estimated for 21 d over a mean feed intake measurement period of 91 d. Animals had a mean daily methane emissions (DME) of 229.18 g/d (SD = 45.96), methane yield (MY) of 22.07 g/kg of DMI (SD = 4.06), methane intensity (MI) 0.70 g/kg of carcass weight (SD = 0.15), and RME 0.00 g/d (SD = 0.34). RME was computed as the residuals from a multiple regression model regressing DME on DMI and BW (R2 = 0.45). Animals were ranked into three groups namely high RME (>0.5 SD above the mean), medium RME (±0.5 SD above/below the mean), and low RME (>0.5 SD below the mean). Low RME animals produced 17.6% and 30.4% less (P < 0.05) DME compared with medium and high RME animals, respectively. A ~30% reduction in MY and MI was detected in low versus high RME animals. Positive correlations were apparent among all methane traits with RME most highly associated with (r = 0.86) DME. MY and MI were correlated (P < 0.05) with DMI, growth, feed efficiency, and carcass output. High RME had lower (P < 0.05) ruminal propionate compared with low RME animals and increased (P < 0.05) butyrate compared with medium and low RME animals. Propionate was negatively associated (P < 0.05) with all methane traits. Greater acetate:propionate ratio was associated with higher RME (r = 0.18; P < 0.05). Under the ad libitum feeding regime deployed here, RME was the best predictor of DME and only methane trait independent of animal productivity. Ranking animals on RME presents the opportunity to exploit interanimal variation in enteric emissions as well as providing a more equitable index of the methanogenic potential of an animal on which to investigate the underlying biological regulatory mechanisms.

280 Relationship of gene markers to residual feed intake, ADG, and marbling of four years of MSU Steer-A-Year steers

Abstract Feeding cattle is one of the largest expenses in beef production systems. Genetic testing has been proposed as a tool to help select livestock that are the most efficient, with greater performance and/or carcass yield or quality. Improved beef cattle performance, increased feed efficiency, and increased carcass value are ongoing goals for beef cattle production. For this study, 118 mix breed feedlot calves were genetically tested with The Merial Ltd (Deluth, GA) Igenity GGP Bovine 50K. We compared genotypic and phenotypic average daily gain (ADG), residual feed intake (RFI) and marbling. Igenity scores were not related to ADG in years 1, 2, and 3 (P &amp;gt; 0.14), but were correlated in year 4 (P &amp;lt; 0.01; r = -0.58). Steer RFI displayed no relationship to the Igenity RFI score (P ≥ 0.29). No linear relationships were observed between actual and predicted marbling but did display tendencies to rank animals similar to actual marbling in years 3 and 4 (P ≤ 0.08; P = 0.34, 0.31, respectively). In summary, we did not see a strong relationship between genetic marker predictions and actual performance characteristics. However, relationships appear to be stronger in later years, suggesting more work is needed to validate genetic markers correlation to feedlot performance.

МЕТОДИКА ОЦЕНКИ ЭФФЕКТИВНОСТИ МЕТОДА ИНДЕКСНОЙ СЕЛЕКЦИИ В ОВЦЕВОДСТВЕ

Evaluation of animals simultaneously on several economically useful features allows to get a complex numerical indicator, based on which it is possible to rank animals. This approach allows you to identify the best animals and determine the strategy of the breeding work. The successful result of the selection work is the production of offspring with high values of selected economically useful traits. This raises the question of the effectiveness of selecting animals based on breeding indices for the breeding work. Thus, the presented research is relevant and will help to evaluate the effectiveness of using the index selection method. The research uses methods of set theory. The entire sample of evaluated rams is divided into two sets. The first set includes sheep with high values of breeding indexes, and the second set includes sheep whose values of economically useful traits are less than the average values. Then the offspring of the evaluated rams are analyzed. In the course of this analysis, it is found out whether rams with a high value of breeding indexes have the same highly productive offspring or not. The article draws attention to the fact that for an objective assessment of the effectiveness of the index selection method, such calculations must be performed on a large number of samples. You need to use data for several years. The best result can be obtained if you analyze the same group of animals for several years. This approach can be implemented in farms that have collected correct databases of animal bonuses that combine data for several years. An integrated Matlab package was used to calculate selection indexes and perform operations on sets. The article is illustrated with numerical data presented in the form of tables and diagrams. The conclusions obtained in the course of the work can help researchers and breeders in improving the efficiency of breeding work using information and computer technologies.

Provocation of life functions at a unicellular eukaryote level by extremely low doses of mammalian hormones: Evidences of hormesis.

Hormones, characteristic to higher ranked animals, are synthesized, stored, and secreted by unicellular eukaryote animals. The unicells also have receptors for recognizing these materials and transmit the message into the cells for provoking response. The hormones are effective in very low concentrations (down to 10-21M) and opposite effects of lower and higher concentrations can be observed. However, sometimes linear concentration effects can be found, which means that hormesis exists, nevertheless uncertain, as it is in the phase of formation (evolutionary experimentation). Hormesis, by transformation (fixation) of cytoplasmic receptor-like membrane components to receptors in the presence of the given hormone, likely helps the development of unicellular endocrine character and by this the evolution of endocrine system. The effect by extremely low concentrations of hormones had been forced by the watery way of unicellular life, which could establish the physiological concentrations of hormones in the blood of higher ranked animals. This means that hormetic low doses are the normal, effective concentrations and the high concentrations are artificial, consequently could be dangerous.

Dominant and Subordinate Relationship Formed by Repeated Social Encounters Alters Gut Microbiota in Greater Long-Tailed Hamsters.

Social stress can dramatically influence the health of animals via communication between gut microbiota and the HPA system. However, this effect has been rarely investigated among different social ranked animals after chronic repeated social encounters. In this study, we evaluated changes and differences in microbiota among control, dominant, and subordinate male greater long-tailed hamsters (Tscherskia triton) over 28 successive days of repeated social encounter. Our results indicated that as compared with the control group, short-term repeated social encounters significantly altered fecal microbiota of subordinate hamsters, while chronic repeated social encounters altered colonic mucosa-associated microbiota of both dominant and subordinate hamsters. Fecal microbiota showed a transition in composition and diversity on day 2 for the subordinate group but on day 4 for the control and dominant groups under repeated encounters. Compared with their baseline, genus Lactobacillus increased in both dominant and subordinate groups, while genus Bifidobacterium increased in the subordinate group and genus Adlercreutzia increased in the dominant group. Our results suggest that chronic repeated social encounter can alter diversity and composition of gut microbiota of hamsters in both feces and colonic mucosa, but the latter performed better in reflecting the effects of chronic stress on microbiota in this species. Future studies should focus on elucidating how these microbiota alterations may affect animal behavior and fitness.

Influences of demographic, seasonal, and social factors on automated touchscreen computer use by rhesus monkeys (Macaca mulatta) in a large naturalistic group.

Animals housed in naturalistic social groups with access to automated cognitive testing vary in whether and how much they participate in cognitive testing. Understanding how demographic, seasonal, and social factors relate to participation is essential to evaluating the usefulness of these systems for studying cognition and in assessing the data produced. We evaluated how sex, age, reproductive experience, seasonality, and rank related to patterns of participation in a naturalistic group of rhesus monkeys over a 4-year period. Females interacted with the touchscreen systems more than males and were more likely to complete initial training. Age was positively correlated with touchscreen activity through adolescence in females, at which point seasonality and reproductive experience were stronger associates of participation. While monkeys in different rank categories did not differ in how much they interacted with the touchscreen systems, monkeys of different ranks tended not to work at the same times, perhaps reflecting avoidance of high ranking animals by those of lower rank. Automated cognitive testing systems for naturalistic social groups of rhesus monkeys can yield quality cognitive data from individuals of all ages and ranks, but participation biases may make it difficult to study sex differences or seasonal variation in cognition.

Behavioral Outcome after Exposure to Two Different Rewarding Stimuli Depends on Social Status

Several studies have described the important role of social environment on dimensions of behavior such as mental health and cognitive performance. Specifically, social rank has been found to affect how individuals respond after significant social experiences such as isolation. Although changes in medial prefrontal cortex (mPFC) activity play a role in the establishment of social rank, few studies have assessed how animals of different positions in the hierarchy process, interact, and respond to different stimuli. Firstly, we analyzed the relationship among stress, adult hippocampal neurogenesis (AHN) and social rank. Secondly, we studied how the exposure to two different types of rewarding stimuli, such as physical exercise and female interaction, affect (i) the social behavior of differently ranked animals, and (ii) adult hippocampal neurogenesis and signaling pathways. No differences were found between animals of different rank in stress‐like behavior, anxiety, and AHN, but we found differential gene expression in mPFC. We also found that female exposure induces subtle different responses in the sociability of animals depending on their rank, as dominant animals presented a trend for an increased social preference after female interaction compared to naïve mice, and 3 weeks of treadmill exercise significantly increased the social preference of dominant animals. We analyzed Oxt+ cell density in the paraventricular nucleus of the hypothalamus and no differences were found among groups in naïve conditions and after female exposure. Moreover, we found that 3 weeks of treadmill increased phosphorylated ERK in dominant mice, produced no changes in neurogenesis depending on the rank but microarray analyses showed differential gene expression among experimental groups. Together, these data suggest that the position of an individual in a social hierarchy may alter the way reward information is processed and unveils an unexplored role of social hierarchy in the development of activity‐induced behaviors.Support or Funding InformationWork was supported by project grants from Spanish Ministry of Economy and Competitiveness BFU2013‐48907‐R and BFU2016‐77162‐R (to J.L.T.). A.P. was funded by an FPI grant, and K.R.McG. was funded by a contract associated with the project grants above mentioned (to J.L.T.).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Strategies for within-litter selection of piglets using ultra-low density SNP panels

Genotyping costs and the large number of selection candidates are major factors that inhibit the application of genomic selection in the swine industry and other small-sized livestock species. In order to reduce genotyping costs and increase the uptake of genomic selection, a possible strategy is to genotype animals with an affordable low-density (LD) SNP panel and, then accurately impute the LD panel to a high-density (HD) SNP panel. For within-litter piglet selection, genotyping all piglets from all farrows using the commercially available SNP chips is still cost prohibitive. Consequently, genomic evaluation is limited in this stage and genotypic and phenotypic data from all piglets in a litter are rarely available. This study investigates the feasibility of implementing genomic selection for within-litter piglet selection, using a total of nine simulated LD panels: from the “ultra” low (300–3000 SNP markers) to moderately low (6000–10, 000 SNP markers). For each LD panel, the performance of the genomic predictions according to the accuracy of genotype imputation, the accuracy of the genomic estimated breeding values (GEBV) based on the imputed data, and distribution of the correctly selected animals within litter was evaluated and compared to using the simulated HD panel (60,000 SNP) and True Breeding Values (TBVs). In this simulation study, we considered three economically important traits: back fat thickness (BF), growth rate of age to 100 Kg (GR), and litter size (LS). For the LD panel sizes ranging from 300 to 10,000, the accuracy of imputation (measured as concordance rate) ranged from 73.20 to 99.81%; and the mean proportion of the correctly selected top rank animals within litter ranged from 55 to 98%. Based on the trade-off between panel size and genomic selection accuracy, the use of a LD panel containing 1500 SNPs might be recommended, as this panel yielded more than 85% correctly selected animals within-litter based on all three traits.

Variation in fibroblast expression of toll-like receptor 4 and lipopolysaccharide-induced cytokine production between animals predicts control of bacterial growth but not severity of Escherichia coli mastitis

Mastitis caused by environmental pathogens such as Escherichia coli is highly problematic to the dairy industry because it incurs substantial cost and tends to be difficult to manage. An effective innate immune response by the host is key to controlling infection, but it should also limit collateral damage to the mammary gland. Between-animal differences in mastitis severity have been attributed to variability in the innate response. In the current study, we used primary dermal fibroblast as a model to rank animals based on composite expression of the toll-like receptor 4 gene (TLR4) and lipopolysaccharide (LPS)-induced IL-8 and IL-6 protein production. Animals ranked as high and low responders (HR and LR, respectively) were then infected with the P4 strain of E. coli to determine how difference in rank would affect response to mastitis. All animals developed an acute response to the infection with varying degrees in severity; however, HR animals had an elevated somatic cell count and fever response at 12 h post-infection and greater production of milk IL-8 at 24 h post-infection. The HR animals were also significantly more capable of limiting bacterial growth. No differences in post-infection milk production or concentrations of milk BSA were measured. The current study indicates that HR animals have an early upregulation in their innate response that is beneficial for bacterial clearance; however, they are equally susceptible to tissue damage caused by an exuberant response to the infection. The dermal fibroblast may be used in conjunction with other cell types to determine how the innate response is regulated to mitigate unnecessary injury to the mammary gland while still effectively clearing the pathogen.

Importance of Behavioral Aspects and Its Implications on Physiological Status, Relationships and Production of Dairy Animals

In the milk producing industry, most of the behavioural aspects of mother-offspring bond, relationships with the stockperson, impact of shifting of cows during lactation stage are discouraged although milk production is sustained with the demand but the behaviour of animals has been shown to play a central role indicating the low production rate and welfare issues from the point of feeding to formation of bond with its calf as well as stockperson. Dairy animals are highly socialized animals to engage in many complex interactions to communicate for dominance, subordination and bonding within the group to form linear social hierarchical structure in a herd. Feeding behavior is influenced by feed bunk, position of body; age/stage of animals, feeding interval and displacement of feed by high and low rank animals which has significant effect on DMI and milk production. Temperament is one of the important factors of milking behaviour in dairy animals which affects the milk yield of a herd. Sudden or excessive shifting of animals between groups or herds significantly lowers the production rate in a herd by increasing the physiological biomarkers. Good maternal behaviour is the key feature of production system which enhances the suckling instinct, fastened let down time of milk; maintain the lactation yield through lowering the stress and strong maternal-offspring bond. The stockpersonÂ’s attitudes always have an effect on the welfare of the animals by improving the handling and positive attitudes. Comfort around resting for welfare of animals can be achieved by monitoring the animalÂ’s behaviour in all aspects of rearing system and management to get the profitable and sustainable livestock production.

Stress and immunological response of heifers divergently ranked for residual feed intake following an adrenocorticotropic hormone challenge

BackgroundWhen an animal is exposed to a stressor, metabolic rate, energy consumption and utilisation increase primarily through activation of the hypothalamic-pituitary-adrenal (HPA) axis. Changes to partitioning of energy by an animal are likely to influence the efficiency with which it is utilised. Therefore, this study aimed to determine the physiological stress response to an exogenous adrenocorticotropic hormone (ACTH) challenge in beef heifers divergently ranked on phenotypic residual feed intake (RFI).ResultsData were collected on 34 Simmental weaning beef heifers the progeny of a well characterized and divergently bred RFI suckler beef herd. Residual feed intake was determined on each animal during the post-weaning stage over a 91-day feed intake measurement period during which they were individually offered adlibitum grass silage and 2 kg of concentrate per head once daily. The 12 highest [0.34 kg DM/d] and 12 lowest [−0.48 kg DM/d] ranking animals on RFI were selected for use in this study. For the physiological stress challenge heifers (mean age 605 ± 13 d; mean BW 518 ± 31.4 kg) were fitted aseptically with indwelling jugular catheters to facilitate intensive blood collection. The response of the adrenal cortex to a standardised dose of ACTH (1.98 IU/kg metabolic BW0.75) was examined. Serial blood samples were analysed for plasma cortisol, ACTH and haematology variables. Heifers differing in RFI did not differ (P = 0.59) in ACTH concentrations. Concentration of ACTH peaked (P < 0.001) in both RFI groups at 20 min post-ACTH administration, following which concentration declined to baseline levels by 150 min. Similarly, cortisol systemic profile peaked at 60 min and concentrations remained continuously elevated for 150 min. A RFI × time interaction was detected for cortisol concentrations (P = 0.06) with high RFI heifers had a greater cortisol response than Low RFI from 40 min to 150 min relative to ACTH administration. Cortisol response was positively associated with RFI status (r = 0.32; P < 0.01). No effect of RFI was evident for neutrophil, lymphocytes, monocyte, eosinophils and basophil count. Plasma red blood cell number (6.07 vs. 6.23; P = 0.02) and hematocrit percentage (23.2 vs. 24.5; P = 0.02) were greater for low than high RFI animals.ConclusionsEvidence is provided that feed efficiency is associated with HPA axis function and susceptibility to stress, and responsiveness of the HPA axis is likely to contribute to appreciable variation in the efficiency feed utilisation of cattle.

1199 Analysis and review of publicly available GreenFeed results

The GreenFeed is a novel tool for measurement of enteric methane (CH4) from ruminant animals. The GreenFeed method uses repeated short-term measurement of CH4 emitted from the animal in a feed trough while animals are receiving a feed reward. To date, over 50 papers, conference proceeding, and reports are available that have used GreenFeed. The research covers a wide range of applications including method comparisons, animal genetics and dietary studies, and on-farm use. In many studies, variability and repeatability of the GreenFeed data are reported. The objective of this study was to aggregate the public data, analyze the results for overall accuracy compared to reference methods, summarize variability and repeatability of CH4 emissions across applications, and to determine the strength of individual animal ranking relationships. Overall, 22 method comparison trails ranging in herd averaged emission from 150–485 g/d have been completed comparing GreenFeed to either the Sulfur Hexafluoride tracer method (SF6, 11 trials), respiration chambers (9 trials), or model predictions (2 trials). The herd averaged results for the reference method compared to GreenFeed showed no significant slope bias (Reference = 0.99 × greenFeed, R2 = 0.99) and the average absolute mean error for all trails was 6.4%. For individual animal CH4 emissions, GreenFeed measured CH4 emissions were positively and moderately-to highly correlated with respiration chamber, SF6, or modeled CH4 in all but 4 trials. In the 4 trials with less agreement for individual animals, the number of GreenFeed samples per animal was very low for some animals (4–10 samples) or there was no chamber replication. GreenFeed measured CH4 for individual animals also showed moderate correlations with DMI in three studies (r2 = 0.73, r2 = 0.61, r = 0.77), and in other studies was found to be higher (r2 = 0.42 and r2 = 0.47) than for SF6 (r2 = 0.17, r2 = 0.08). Between animal variation in GreenFeed CH4 emissions were found to be the same, or lower than between animal variation in DMI, BW, or Respiration Chambers, or SF6 in all but one trail. Long term repeatability (R) of GreenFeed CH4 emissions on forage based diets was R = 0.70- 0.88 in 7 different trials. Overall, the GreenFeed method produced similar absolute CH4emissions estimates to reference methods, demonstrated the ability to rank animals, produced low but accurate between animal variability, and was highly repeatable on forage diets.

Lectins and Tetrahymena - A review.

The unicellular ciliate Tetrahymena is a complete organism, one of the most highly developed protozoans, which has specialized organelles performing each of the functions characteristic to the cells of higher ranked animals. It is also able to produce, store, and secrete hormones of higher ranked animals and also react to them. It produces lectins that can bind them and has functions, which are influenced by exogenous lectins. The review lists the observations on the relationship between lectins and Tetrahymena and try to construe them on the basis of the data, which are at our disposal. Considering the data, lectins can be used by Tetrahymena as materials for influencing conjugation, for stimulating hormone receptors, and by this, mimic the hormonal functions. Lectins can influence phagocytosis and movement of the cells as well as the cell division. As Tetrahymena can recognize both related and hostile cells by the help of lectins and surface sugars, it could be surmised a complex predator-prey system. This could determine the survival of the population as well as the nourishment conditions. When Tetrahymena is pathogenic, it can use lectins as virulence factors.

Important role of dominance in allogrooming behaviour in beef cattle

In domestic cattle, the relationship between dominance and allogrooming behaviour has been investigated in several studies. However, the results do not show a consistent pattern. The aim of this study was to investigate this relationship in a stable female beef cattle herd using social network analysis as a novel methodological approach. We tested two adaptive allogrooming hypotheses. The ‘Grooming-for-Commodity’ hypothesis posits that allogrooming is directed from low ranking animals towards higher ranking cows in exchange of tolerance and other favours. The ‘Grooming-for-Stability’ hypothesis predicts that allogrooming is performed by high ranking animals down the hierarchy in order to perpetuate the stability of the social structure. We recorded a herd of 15 Gasconne cows on pasture for 3 weeks (180h) and recorded 681 agonistic interactions and 288 allogrooming events. To evaluate the relationship between dominance and allogrooming behaviour we calculated correlations between dominance index, individual behavioural effort (OUT-direction), and individual attractiveness (IN-direction). We found that more dominant animals provided much higher amount of allogrooming acts (p<0.001) and groomed more herdmates (p<0.001). As a consequence, allogrooming behaviour was mostly oriented down the hierarchy (p<0.001). At the same time, more dominant animals also received higher total number of allogrooming (p<0.05). This seeming paradox was due to the fact that the very active high ranking allogroomers exchanged a lot of the licking with each other. Further, the dominance index of the cow was or tended to be positively related to the social network analysis measures of IN-Dyad-Reciprocity (p=0.065), IN-Betweenness (p<0.05) and OUT-Dyad-Reciprocity (p<0.001). Our study showed that the more dominant animals have more prominent roles in the allogrooming network of a stable female beef cattle herd. These results give more support to the ‘Grooming-for-Stability’ hypothesis than to the ‘Grooming-for-Commodity’ hypothesis.

Endocrine and hematological responses of beef heifers divergently ranked for residual feed intake following a bovine corticotropin-releasing hormone challenge.

The objective of this study was to determine if beef heifers divergently ranked on phenotypic residual feed intake (RFI) differed in their physiological stress response to an exogenous bovine corticotropin-releasing hormone (bCRH) challenge. Yearling Limousin × Friesian heifers ( = 86) were ranked by RFI. The 15 highest (mean 0.66 kg DM/d; high RFI) and 15 lowest (mean -0.72 kg DM/d; low RFI) ranking animals were used for this study. During the study period, heifers (mean age 485 ± 13 d; mean BW 408 ± 31.4 kg) were housed in a slatted-floor facility. To facilitate intensive blood collection, heifers were fitted aseptically with indwelling jugular catheters. All heifers received dexamethasone (DEX; 20 µg/kg BW i.m.) 12 h before the bCRH challenge (d 0). Heparinized blood samples were collected at -60 and 0 min before administration of DEX, and 12 h after DEX administration. Following DEX administration, cortisol and dehydroepiandrosterone (DHEA) concentrations similarly decreased ( ≥ 0.22) between high and low RFI groups. The response of the HPA axis to a standardized dose of bCRH (0.3 μg/kg BW) was examined. On d 0, serial blood samples were collected at -20, 0, 20, 40, 60, 80, 100, 120, 150, 180, 210, 240, 270, 330, and 390 min relative to the time of bCRH administration (0 min) and were analyzed for plasma cortisol and DHEA concentrations. Blood hematology variables were also determined at -20, 0, 20, 80, 150, 270, 330, and 390 min relative to bCRH administration. Neither an RFI × sampling time interaction nor a direct effect of RFI were detected ( ≥ 0.36) for plasma cortisol, DHEA concentrations, or cortisol:DHEA ratio. An effect of sample time was observed for cortisol ( < 0.001), DHEA ( = 0.04), and cortisol:DHEA ( = 0.02), with cortisol concentration peaking at 60 min post-CRH administration. The maximum concentration and rate of change in cortisol and DHEA concentrations following bCRH administration were not different ( ≥ 0.20) between the high and low RFI phenotypes. Similarly, an effect of RFI was not evident ( ≥ 0.16) for any of the hematology variables examined including neutrophil, lymphocyte, and leukocytes counts; white and red blood cell numbers; and hemoglobin concentrations. Our results suggest that responsiveness of the HPA to stress, at least at the level of the anterior pituitary gland, is not a significant contributor to variation in RFI among growing beef heifers.