Livestock and climate change, challenges and options

Abstract

This review outlines livestock's major emission pathways and production trends, and explores the challenges and options for livestock in addressing and coping with climate change. Ruminant production is, and will continue to be, the chief source of the livestock sector's greenhouse gas (GHG) emissions, mainly as a result of deforestation, land degradation and enteric fermentation. Livestock productivity improvement is fundamental to mitigation and where it is achieved through the transfer of improved production practices and technologies, it can also deliver important rural livelihood and food security co-benefits in developing countries. Mitigation is also possible by shifting production resources, particularly concentrate feeds, from ruminant to monogastric enterprises, given their higher feed conversion efficiencies and lower emission intensities. However, standard prescriptions for productivity improvements, which are often accompanied by higher concentrations of animals on land, need safeguards to ensure that they do not lead to localized pollution problems and increase disease risks. Further, measures that simultaneously improve productivity and capacity for adaptation to climate change, such as more efficient crop-livestock integration and water management, should be exploited wherever possible. Policy options for unlocking livestock's large mitigation potential are widely known, but their implementation is currently hampered by technical and institutional capacity constraints, and by a lack of political support and global agreement on mitigation. There is a particular need for practicable methods for measurement, reporting and verification of emissions, to improve access to carbon markets, and to facilitate the sector's transition to a low-emission future.

Socioeconomic status, pathogen burden and cardiovascular disease risk

OBJECTIVE

Socioeconomic status (SES) is inversely associated with coronary heart disease (CHD) risk. Cumulative pathogen burden may also predict future CHD. The hypothesis was tested that lower SES is associated with a greater pathogen burden, and that pathogen burden accounts in part for SES differences in cardiovascular risk factors.

METHODS

This was a cross-sectional observational study involving the clinical examination of 451 men and women aged 51-72 without CHD, recruited from the Whitehall II epidemiological cohort. SES was defined by grade of employment, and pathogen burden by summing positive serostatus for Chlamydia pneumoniae, cytomegalovirus and herpes simplex virus 1. Cardiovascular risk factors were also assessed.

RESULTS

Pathogen burden averaged 1.94 (SD) 0.93 in the lower grade group, compared with 1.64 (0.97) and 1.64 (0.93) in the intermediate and higher grade groups (p = 0.011). Pathogen burden was associated with a higher body mass index, waist/hip ratio, blood pressure and incidence of diabetes. There were SES differences in waist/hip ratio, high-density lipoprotein-cholesterol, fasting glucose, glycated haemoglobin, lung function, smoking and diabetes. The SES gradient in these cardiovascular risk factors was unchanged when pathogen burden was taken into account statistically.

CONCLUSIONS

Although serological signs of infection with common pathogens are more frequent in lower SES groups, their distribution across the social gradient does not match the linear increases in CHD risk present across higher, intermediate and lower SES groups. Additionally, pathogen burden does not appear to mediate SES differences in cardiovascular risk profiles.

Protective effect of human heat shock protein 60 suggested by its association with decreased seropositivity to pathogens

The presence of heat shock protein 60 (Hsp60) in human plasma has been linked with cardiovascular disease (CVD). In this study, the examination of the relationship between Hsp60 in plasma and seropositivity for three microbial agents, which are thought to be risk factors for CVD, surprisingly revealed a negative association between Hsp60 and seropositivity, suggesting a protective effect of this circulating stress protein.

Occupational asthma prevention and management in industry--an example of a global programme

Isocyanates are widely used in the manufacture of polyurethane foams, plastics, coatings and adhesives, and are known to cause occupational asthma in a proportion of exposed workers. Substitution as a prevention strategy is not currently a feasible option. For this reason, health and safety professionals working together in an automotive coatings business created a proactive global programme to address the known potential effects of isocyanates on its workers. The goals of the programme are prevention, early detection and mitigation of effect of key endpoints, especially asthma and to a lesser degree dermatitis, in people who are occupationally exposed, or potentially exposed, to isocyanates and products containing isocyanates. The surveillance programme for isocyanates has several important components, which include assessment of exposure, pre-placement questionnaire and spirometry, training and education of employees, regularly administered periodic questionnaires, medical assessment for abnormal questionnaire responses, process for early reporting and investigation of symptomatic employees and incidents, group data review and management reporting. Although regional differences exist regarding availability of specialized services, we have successfully implemented this programme in parts of North America, Europe and Latin America, and are currently implementing elsewhere. These simple control measures are relatively inexpensive and can be applied in even small business settings. It is recommended that all employers who manufacture, handle or use isocyanate-containing products consider such a strategy.

The psychological impact of mammographic screening. A systematic review

Concerns have been raised regarding the possible negative psychological impact of the cancer screening programmes offered in the UK. This review aims to assess the extent of and factors associated with the adverse psychological consequences of mammographic screening. Fifty-four papers from 13 countries were identified, a majority of which were published after 1990, coinciding more or less with the onset of routine mammographic screening. The results report that mammographic screening does not appear to create anxiety in women who are given a clear result after a mammogram and are subsequently placed on routine recall. However, women who have further investigations following their routine mammogram experience significant anxiety in the short term, and possibly in the long term. The nature and extent of the further investigation that women are exposed to during mammographic screening determines the intensity of the psychological impact. Factors associated with the adverse psychological impact of mammographic screening included: social demographic factors of younger age, lower education, living in urban areas, manual occupation, and one or no children; cancer screening factors of dissatisfaction with information and communication during screening process, waiting time between recall letter and recall appointment, pain experienced during the mammographic screening procedures, and previous false positive result; and cancer worry factors including fear of cancer and greater perceived risk of breast cancer. Difficulties in measuring the psychological impact of screening are discussed, and methods of alleviating the negative psychological outcomes are suggested.

6 EXPRESSION PROFILING OF SINGLE BOVINE EMBRYOS REVEALS SIGNIFICANT EFFECTS OF IN VITRO MATURATION, FERTILIZATION AND CULTURE

Cattle and sheep embryos transferred after in vitro production are often afflicted by large offspring syndrome (LOS), which has been correlated with the presence of serum and/or cell co-culture. Previous research indicates that post-fertilization culture affects blastocyst quality and gene expression, and in vitro oocyte maturation and fertilization impact developmental competence. To dissect the effects of in vitro maturation, fertilization, and culture, we compared the expression profiles of single bovine blastocysts generated by: (1) in vitro maturation, fertilization and culture (IVF, n = 15); (2) in vivo maturation, in vivo fertilization, and in vitro culture (IVD, n = 14); and (3) in vivo maturation, fertilization, and development (AI, n = 14). For in vitro culture, the embryos were cultured for 2 days in CR1aa medium with bovine serum albumin (BSA) and then transferred to CR1aa with 10% fetal bovine serum (FBS) with cumulus cells until Day 7, at which time the embryos were vitrified. IVD zygotes were surgically collected from two superovulated Holstein donor cows 24 h post-insemination and cultured in the same system. To conduct expression profiling, total RNA was isolated from individual thawed embryos. The RNA was subjected to three rounds of amplification utilizing a previously adapted and validated T7 linear amplification protocol. Amplified RNA from each embryo and from a standard reference was indirectly labeled with Cy3 or Cy5 by dye swap and hybridized to a custom bovine cDNA microarray containing ~6300 unique genes. After Loess normalization, an ANOVA model (GeneSpring 6.1 and SAS 9.0) was used to identify differentially expressed genes. The P-values were adjusted for multiple comparisons using the false discovery rate approach, and a e2-fold differential criterion was applied. A subset of the differentially expressed genes was verified by real-time RT-PCR. The blastocyst rates for IVF and IVD embryos were 37% and 75%, respectively. There were 305, 365, and 200 genes differentially expressed between the AI and IVD, the IVF and IVD, and the AI and IVF comparisons, respectively. Interestingly, 44 differentially expressed genes were identified between the AI embryos and both the IVF and the IVD embryos, making these potential candidates for LOS. There were 61 genes differentially expressed between the IVF embryos and the AI and IVD embryos. The Gene Ontology categories 'RNA processing' and 'RNA binding' were over-represented among the genes that were down-regulated in the IVF embryos, indicating an effect of in vitro oocyte maturation/fertilization on embryonic gene expression. This work was supported by USDA grants to X.Y., H.A.L., and X.C.T.

TNF- neutralization in cytokine-driven diseases: a mathematical model to account for therapeutic success in rheumatoid arthritis but therapeutic failure in systemic inflammatory response syndrome

OBJECTIVES

Neutralization of TNF-alpha with either monoclonal antibodies or soluble receptors, although not curative, has significant clinical benefit in patients with rheumatoid arthritis (RA). In contrast, blockade of TNF-alpha has little clinical benefit in the majority of patients with systemic inflammatory response syndrome (SIRS) in spite of the identification of TNF-alpha as a key factor in its pathology. It is not clear why there is such a significant difference in the responses to TNF-alpha neutralization in these two conditions. Here we use mathematical modelling to investigate this discrepancy.

METHODS

Using the known pharmacokinetic and pharmacodynamic properties of TNF-alpha-blocking biological agents, we constructed a mathematical model of the biological actions of soluble(s) TNFR2, Etanercept and Infliximab.

RESULTS

Our model predicts that all three inhibitors, but especially Etanercept, are effective at controlling TNF-alpha levels in RA, which we propose is a condition in which TNF-alpha production and inhibition are in equilibrium. However, when free TNF-alpha drops to a low level, as can occur in SIRS, which we propose is a non-equilibrium condition, the sequestered TNF-alpha can act as a slow-release reservoir, thereby sabotaging its effectiveness.

CONCLUSIONS

These results may explain the effectiveness of TNF-alpha blockade in the equilibrium condition RA and the ineffectiveness in the non-equilibrium condition SIRS.

202 GENETIC INFLUENCE ON FOLLICULAR DEVELOPMENT IN CATTLE

In cattle, the development of ovarian follicles >5 mm occurs in waves. During each estrus cycle, a cohort of 5–7 follicles develops either 2 or 3 times, with the last wave containing the ovulatory follicle. It is speculated that follicular wave number within estrus cycle may be genetically determined; however, no data have been published to support this hypothesis. The present study was designed to test this hypothesis by using genetically identical cloned cows and comparing their wave patterns among each other and to those of control animals by studying their ovarian follicular dynamics. Three 5-yr-old cloned cows, derived from somatic cells of a 13-yr-old Holstein dairy cow, were age- and lactational status-matched with contemporary cows produced by AI, and maintained under the same managemental conditions. Ovarian follicular dynamics of all the cows were determined using a real-time, B-mode, linear-array ultrasound scanner equipped with a 7.5 MHz transrectal transducer (Aloka Co., Tokyo, Japan). Ultrasound examinations were carried out every day for 101 days and covered 4 estrus cycles for each animal. For tracking the follicular dynamics, daily ultrasound observations were videotaped and individual follicle dimension and location were drawn. The estrus was determined by the visual observation of a growing follicle over a period of several days, reaching a maximum diameter of about 15 mm or more, and its subsequent disappearance on the following day. The ultrasound observations were corroborated with the visual and behavioral signs of estrus. The average length of estrus cycle in clones and controls was 23.08 ± 0.47 days and 22.67 ± 0.37 days (mean ± SEM), respectively, and were not significantly different. Out of the four estrus cycles studied, all clones showed 3 follicular waves in 3 cycles and 2 waves in one cycle. However, the wave pattern within each cycle did not match for the clones over all the cycles. In controls, one cow had 2 waves in all 4 cycles while the other two cows had both 3- as well as 2-wave cycles. The 3-wave cycles had an average length of 23.89 ± 0.59 days (mean ± SEM) and 24.00 ± 0.71 days in clones and controls, and the average lengths of 2-wave cycles were 20.67 ± 0.33 d and 22.00 ± 0.38 d in clones and controls, respectively. There was no significant difference in the average cycle lengths among the three clones, which were 23.00 ± 1.23, 23.75 ± 1.38, and 22.50 ± 0.65 days. Over the 4 estrus cycles, the clones and the controls had a total of 60.33 ± 7.45 and 63.00 ± 6.12 small (4 mm–<6 mm), 63.74 ± 6.34 and 69.00 ± 9.62 medium (6 mm–10 mm), and 22.00 ± 2.51 and 20.00 ± 1.16 large (>10 mm) follicles, respectively. The total number of follicles for each clone during 4 cycles were different, viz., large (25, 17, 24), medium (60, 76, 55), and small (71, 64, 46). Thus the clones, in spite of their shared genetic makeup, had different cycle lengths, follicle numbers, and follicular wave patterns. This indicates that genetic makeup is not the only major influence determining bovine follicular dynamics.

Effect of Mycobacterium tuberculosis chaperonins on bronchial eosinophilia and hyper-responsiveness in a murine model of allergic inflammation

BACKGROUND

Epidemiological evidence suggests that infection with Mycobacterium tuberculosis protects children against asthma. Several laboratories have shown that, in mouse models of allergic inflammation, administration of the whole live tuberculosis vaccine, Mycobacterium bovis bacillus Calmette-Guerin (BCG), prevents ovalbumin (OVA)-induced pulmonary eosinophilia.

OBJECTIVE

The aim of this study was to characterize specific M. tuberculosis molecules that are known to modulate immune responses to see if they affected pulmonary eosinophilia and bronchial hyper-responsiveness.

METHODS

C57Bl/6 mice were sensitized to OVA on days 0 and 7 and subsequently challenged with OVA on day 14 over a 3-day period. Pulmonary eosinophilia and bronchial hyper-responsiveness were measured 24 h following the last antigen challenge. In some groups, mice were pre-treated with M. tuberculosis or M. tuberculosis chaperonins (Cpns)60.1, 60.2 and 10, and the effect of this treatment on the allergic inflammatory response to aerosolized OVA was established.

RESULTS

We show that M. tuberculosis Cpns inhibit allergen-induced pulmonary eosinophilia in the mouse. Of the three Cpns produced by M. tuberculosis, Cpn60.1, Cpn10 and Cpn60.2, the first two are effective in preventing eosinophilia when administered by the intra-tracheal route. Furthermore, the increase in airways sensitivity to inhaled methacholine following OVA challenge of immunized mice was suppressed following treatment with Cpn60.1. The allergic inflammatory response was also characterized by an increase in Th2 cytokines IL-4 and IL-5 in bronchoalveolar lavage fluid, which was also suppressed following treatment with Cpn60.1.

CONCLUSION

These data show that bacterial Cpns can suppress eosinophil recruitment and bronchial hyper-responsiveness in a murine model of allergic inflammation.

A comparison of competing methods for the detection of surgical-site infections in patients undergoing total arthroplasty of the knee, partial and total arthroplasty of hip and femoral or similar vascular bypass

Recent research suggests that the retrospective review of the International Classification of Disease (ICD-9-CM) codes assigned to a patient episode will identify a similar number of healthcare-acquired surgical-site infections as compared with prospective surveillance by infection control practitioners (ICP). We tested this finding by replicating the methods for 380 surgical procedures. The sensitivity and specificity of the ICP undertaking prospective surveillance was 80% and 100%, and the sensitivity and specificity of the review of ICD-10-AM codes was 60% and 98.9%. Based on these results we do not support retrospective review of ICD-10-AM codes in preference prospective surveillance for SSI.

40PREDICTORS OF CLONED CALF VIABILITY

The high rate of gestational loss in nuclear transfer (NT) pregnancies is a major economic and animal cost, preventing the widespread use of the technique. It is currently not possible to predict which early gestation fetuses will remain viable to term. As placental abnormalties are commonly associated with nonviable fetuses, placental proteins such as pregnancy specific protein (PSP 60, Heyman et al., 2002 Biol. Reprod. 63, 1787–1794; or PSPb Hill et al., 2000 Biol. Reprod. 66, 6–13) have been investigated as possible markers of viable pregnancy. To build upon these studies, we explored the predictive value of Day-35 maternal serum PSPb value to final cloned-calf viability; PSPb profiles throughout pregnancy; and the relationship of maternal plasma estradiol levels to calf viability. Maternal serum was sampled for PSPb at the time of the first ultrasound pregnancy examination (Day 35) to determine fetal number and viability (heartbeat). PSPb values were determined using an RIA by Dr. Garth Sasser (BioTracking, Moscow, ID). Median PSPb values were compared using the Kruskal-Wallis one-way ANOVA test on ranks. PSPb levels from failed single and twin pregnancies were significantly different from those of AI bred controls (P&lt;0.05). PSPb levels from failed singles were not significantly different from those of viable single pregnancies although only nonviable cloned pregnancies had PSPb values &gt;7.5. As PSPb levels at Day 35 were not highly predictive of viable outcome, we detailed the gestational PSPb profile for a different group of cows (n=40) that carried cloned pregnancies beyond Day 90. PSPb was determined at Days 35, 50, 65, and 90, then monthly to Day 240. Although there was no clear statistical significance, PSPb levels from nonviable cloned pregnancies were consistently higher at each time point than for viable pregnancies (14 cows gave birth to live calves) and significantly higher than those of controls. At term, plasma estradiol concentrations were assessed in a group of 5 NT pregnancies. Estradiol was investigated as cloned pregnancies often show a lack of readiness for parturition (e.g. lack of udder development, prolonged gestation, dysmature calves). These 5 pregnancies produced 3 highly viable NT calves: 1 with lowered viability that survived only with a high level of intensive care, and 2 nonviable despite a high level of assistance. In this small group, estradiol levels on the day of birth rose in parallel with viability (viable, 662pg; lowered viability, 170pg; nonviable, 76pg). This is a clinical observation rather than a statistical trend that suggests further investigation may be warranted. In summary, our results suggest maternal PSPb levels have value in identifying the outliers in a population of cloned pregnancies and that term-cloned pregnancies may show abnormally low maternal estradiol concentrations at term. Table 1

34EFFECT OF GENOTYPE AND CELL LINE ON THE EFFICIENCY OF LIVE CALF PRODUCTION BY SOMATIC CELL NUCLEAR TRANSFER

The efficiency of production of live calves using somatic cell nuclear transfer was compared among 52 different cell lines representing 43 different genotypes. Cell lines were not genetically modified. Nuclear transfer was performed according to methods described by Cibelli et al., 1998 Science 280, 1256–1258, with modifications. All cells were derived from either explant cultures or enzyme digests of skin biopsies and were cyropreserved and thawed at least 48 hours prior to nuclear transfer. Cells were harvested using either pronase or trypsin at 70 to 90% confluence. Oocytes were either activated prior to fusion or immediately after fusion using ionomycin. The couplets were then cultured in cycloheximide and cytochalsin B for 6 hours. In 36 cases (84%), at least one healthy calf was produced from the initial trial which included transfer to 10 to 20 recipients for each cell line. For 4 of the 7 cases where the initial cell line failed to produce a live calf, a new cell line was derived and the process repeated. In one case where the data are available from the second cell line, 5 live calves were produced from 20 recipients receiving embryos (25%). Results from the other repeated cell lines are pending. For 5 of the different genotypes, nuclear transfer was done at about the same time using two different cell lines, and 4 of these have produced healthy calves from both cell lines. In one case, one cell line produced live calves, and no calves were produced from the other cell line. In total, 167 calves were born, of which 107 are alive and healthy as of this writing (64%), and range in age from 1 to 25 months. There are 86 calves older than 6 months of age and no losses have occurred as calves have aged into early adulthood. Forty-four (26%) of the calves were stillborn, failed to convert to neonatal circulation or were euthanized within 48 hours of birth. The most frequent reason for euthanasia was severe contracture of the limbs (arthrogryposis). This defect occurred even within cell lines that also gave rise to healthy calves, although it was more prevalent with certain cell lines. Other complications among the normal calves born were those of an abnormally large umbilicus or umbilical vessels. In addition, 16 calves were lost after the first 48 hours (13%). Two of these losses were due to accidents and 9 of them were due to complications from umbilical infections. The other 5 calf loses resulted from complications common to young calves such as clostridial infection and ruptured abomasum. Recent improvements in cell line derivation and embryo culture techniques, as well as a higher incidence of natural birth and improved neonatal management, have resulted in healthy calf production efficiencies (from embryos transferred) greater than 30% for 5 independent genotypes. The number of healthy calves produced per embryo transferred was 11 of 20 (55%), 5 of 10 (50%), 5 of 10 (50%), 4 of 11 (36%), and 3 of 10 (30%), for each of these genotypes, respectively. There was no correlation between the efficiency of blastocyst production and pregnancy outcome for the cell lines evaluated in this study. In conclusion, the efficiency of live healthy calf production using somatic cell nuclear transfer remains variable, depending on both the cell line and the genotype. However, efficiencies approaching those obtained using conventional embryo transfer is possible.