Climate change and broiler production

Climate change has emerged as a significant occurrence that adversely affects broiler production, especially in tropical climates. Broiler chickens, bred for rapid growth and high meat production, rely heavily on optimal environmental conditions to achieve their genetic potential. However, climate change disrupts these conditions and poses numerous challenges for broiler production. One of the primary impacts of climate change on broiler production is the decreased ability of birds to attain their genetic potential for faster growth. Broilers are bred to possess specific genetic traits that enable them to grow rapidly and efficiently convert feed into meat. However, in tropical climates affected by climate change, the consequent rise in daily temperatures, increased humidity and altered precipitation patterns create an unfavourable environment for broilers. These conditions impede their growth and development, preventing them from reaching their maximum genetic influence, which is crucial for achieving desirable production outcomes. Furthermore, climate change exacerbates the existing challenges faced by broiler production systems. Higher feed costs impact the industry's economic viability and limit the availability of quality nutrition for the birds, further hampering their growth potential. In addition to feed scarcity, climate change also predisposes broiler chickens to thermal stress. This review collates existing information on climate change and its impact on broiler production, including nutrition, immune function, health and disease susceptibility. It also summarizes the challenges of broiler production under hot and humid climate conditions with different approaches to ameliorating the effects of harsh climatic conditions in poultry.

Vaginal temperature of lactating cows during heat waves or normal summer day and effect of additional daily cooling treatments as heat load mitigation strategy

The vaginal temperature (VT) of lactating Holstein cows was monitored in not heat wave (NHW) and in heat wave (HW) summer days. Temperature humidity index (THI) was monitored and assigned to four classes of heat load (HL): THI < 68 null; 68 < THI < 74 low; 74 < THI < 80 moderate; and THI > 80 high.Five daily treatments consisting of continuous forced ventilation and sprayed water (1' on follow by 5' off) were assumed as control cooling protocol (CC) and compared with two experimental cooling protocols (EC) applied in the feed bunk and based on the CC plus two additional cooling treatments which lasted a total of 90' (EC90) or 150' (EC150) in the day.Sixty lactating cows were enrolled in two summer trials carried out in NHW or HW. In each trial, 10 cows were cooled by CC, 10 by EC90 and 10 by EC150. Twenty additional cows were monitored in a fall trail to have reference value of THI and VT under thermoneutral conditions (TN). Each trial lasted 72 h, and measurements of VT were carried out by intra-vaginal data loggers.The 33% of observed THI was within the high class of HL during HW, whereas THI never exceeded the upper threshold of moderate or low class of HL in NHW and TN, respectively.Multiparous and high yielding cows were more sensitive to HL, and the increased daily cooling treatments reduced heat load during hot conditions. However, during heat waves a certain degree of hyperthermia occurred even with intensive cooling management based on seven daily treatments.

A system dynamics approach to model heat stress accumulation in dairy cows during a heatwave event

Climate change is expected to increase the number of heat wave events, leading to prolonged exposures to severe heat stress (HS) and the corresponding adverse effects on dairy cattle productivity. Modelling dairy cattle productivity under HS conditions is complicated because it requires comprehending the complexity, non-linearity, dynamicity, and delays in animal response. In this paper, we applied the System Dynamics methodology to understand the dynamics of animal response and system delays of observed milk yield (MY) in dairy cows under HS. Data on MY and temperature-humidity index were collected from a dairy cattle farm. Model development involved: (i) articulation of the problem, identification of the feedback mechanisms, and development of the dynamic hypothesis through a causal loop diagram; (ii) formulation of the quantitative model through a stock-and-flow structure; (iii) calibration of the model parameters; and (iv) analysis of results for individual cows. The model was successively evaluated with 20 cows in the case study farm, and the relevant parameters of their HS response were quantified with calibration. According to the evaluation of the results, the proposed model structure was able to capture the effect of HS for 11 cows with high accuracy with mean absolute percent error <5%, concordance correlation coefficient >0.6, and R2 > 0.6, except for two cows (ID #13 and #20) with R2 less than 0.6, implying that the rest of the nine animals do not exhibit heat-sensitive behaviour for the defined parameter space. The presented HS model considered non-linear feedback mechanisms as an attempt to help farmers and decision makers quantify the animal response to HS, predict MY under HS conditions, and distinguish the heat-sensitive cows from heat-tolerant cows at the farm level.

Sensor-based behavioral patterns can identify heat-sensitive lactating dairy cows

Heat stress impairs the health and performance of dairy cows, yet only a few studies have investigated the diversity of cattle behavioral responses to heat waves. This research was conducted on an Italian Holstein dairy farm equipped with precision livestock farming sensors to assess potential different behavioral patterns of the animals. Three heat waves, defined as at least five consecutive days with mean daily temperature-humidity index higher than 72, were recorded in the farm area during the summer of 2021. Individual daily milk yield data of 102 cows were used to identify "heat-sensitive" animals, meaning the cows that, under a given heat wave, experienced a milk yield drop that was not linked with other health events (e.g., mastitis). Milk yield drops were detected as perturbations of the lactation curve estimated by iteratively using Wood's equation. Individual daily minutes of lying, chewing, and activity were retrieved from ear-tag-based accelerometer sensors. Semi-parametric generalized estimating equations models were used to assess behavioral deviations of heat-sensitive cows from the herd means under heat stress conditions. Heat waves were associated with an overall increase in the herd's chewing and activity times, along with an overall decrease of lying time. Heat-sensitive cows spent approximately 15 min/days more chewing and performing activities (p < 0.05). The findings of this research suggest that the information provided by high-frequency sensor data could assist farmers in identifying cows for which personalized interventions to alleviate heat stress are needed.

A systematic review of the effects of silvopastoral system on thermal environment and dairy cows' behavioral and physiological responses

Does the silvopastoral system (SPS) promote a satisfactory thermal environment for dairy cows to perform their natural behaviors and perform a suitable thermoregulatory function? To answer this, peer-reviewed articles, written in English and evaluating the effects of silvopastoral systems on thermal environment, dairy cows' behavior, and physiology were used in this systematic review; additionally, a bibliometric approach was performed. Web of Science and Google Scholar were used to compile the literature. The resulting articles (1448) underwent a 4-step appraisal process and resulted in 19 articles that fitted our inclusion criteria. Microclimate variables and thermal comfort indicators were the most researched topics (discussed in 89% of studies); 47% of studies addressed cattle behavior and 36% physiological responses. Our review highlights different benefits of silvopastoral systems for grazing dairy cows. For example, the SPS provides a more comfortable thermal environment than treeless pasture, which increases feeding behaviors; furthermore, dairy cows in SPS show lower drinking events, surface temperature, and respiratory rate than cows raised in treeless pasture. However, for nine of the variables related to cows' behavior (e.g., resting, rumination) and physiology responses (e.g., internal temperature), the results of the studies were unclear. Furthermore, behaviors associated with lying down (e.g., idling and rumination) and milk production in SPS were explored only in six and two studies, respectively. These findings provide consistent evidence that the silvopastoral systems are beneficial to thermal comfort of dairy cows; nonetheless, the effect on cows' behavioral and physiological responses is still scarce and unclear.

Multisectoral Perspectives on Global Warming and Vector-borne Diseases: a Focus on Southern Europe

Purpose of Review

The climate change (CC) or global warming (GW) modifies environment that favors vectors' abundance, growth, and reproduction, and consequently, the rate of development of pathogens within the vectors. This review highlights the threats of GW-induced vector-borne diseases (VBDs) in Southern Europe (SE) and the need for mitigation efforts to prevent potential global health catastrophe.

Recent Findings

Reports showed astronomical surges in the incidences of CC-induced VBDs in the SE. The recently (2022) reported first cases of African swine fever in Northern Italy and West Nile fever in SE are linked to the CC-modified environmental conditions that support vectors and pathogens' growth and development, and disease transmission.

Summary

VBDs endemic to the tropics are increasingly becoming a major health challenge in the SE, a temperate region, due to the favorable environmental conditions caused by CC/GW that support vectors and pathogens' biology in the previously non-endemic temperate regions.

Effects of Heat Stress in Dairy Cows Raised in the Confined System: A Scientometric Review

Due to climate change, heat stress is a growing problem for the dairy industry. Based on this, annual economic losses in the dairy sector are verified mainly on a large scale. Despite several publications on thermal stress in lactating dairy cows in confinement systems, there need to be published reviews addressing this issue systematically. Our objective was to scientometrically analyze the effects of heat stress in dairy cows managed in a confinement system. Based on PRISMA guidelines, research articles were identified, screened, and summarized based on inclusion criteria for heat stress in a confinement system. Data was obtained from the Web of Science. A total of 604 scientific articles published between 2000 and April 2022 were considered. Data was then analyzed using Microsoft Excel and CiteSpace. The results pointed to a significant increase in studies on heat stress in lactating cows housed in confinement systems. The main research areas were Agriculture, Dairy Animal Science and Veterinary Sciences. The USA showed the highest concentration of studies (31.12%), followed by China (14.90%). Emerging themes included heat stress and behavior. The most influential journals were the Journal of Dairy Science and the Journal of Animal Science. The top authors were L. H. Baumgard and R. J. Collier. The leading institutions were the Chinese Academy of Agricultural Sciences, followed by the State University System of Florida and the University of Florida. The study maps the significant research domains on heat stress of lactating cows in confinement systems, discusses implications and explanations and highlights emerging trends.

Influence of successive heat waves on the thermoregulatory responses of pregnant and non-pregnant ewes

The frequency of heat waves has increased over the last years, with an impact on animal production and health, including the death of animals. Therefore, the aim of this study was to evaluate the dynamics of thermoregulation and hormonal responses in non-pregnant and pregnant ewes exposed to successive heat waves. Twenty-four non-pregnant and 18 pregnant Santa Ines ewes with black coat color (live weight: 55 ± 9.03 kg; age: 60 months) were used. Weather variables such air temperature, relative humidity, and solar radiation were continuously recorded. The rectal and tympanic temperatures and respiratory rate were measured daily. Serum triiodothyronine (T3) and prolactin were evaluated during the heat wave and thermoneutral periods. The physiological variables were higher under the heat wave conditions and were related to the activation of the thermoregulatory system for maintaining homeothermy (P < 0.05). The core body temperature was higher during successive heat waves (P < 0.05), as was the tympanic temperature, which are both affected by changes in air temperature (P < 0.05). T3 and prolactin levels were not influenced by successive heat waves (P < 0.05) and rectal temperature and respiratory rate were highest in non-pregnant ewes (P < 0.05). Prolactin was not affected by temperature. The results indicate that the Santa Ines breed overcomes the thermal challenge during a heat wave without showing severe signs of thermal stress regardless of being pregnant or not.

Changes in the pattern of heat waves and the impacts on Holstein cows in a subtropical region

This study aimed to evaluate the change in the air temperature and the impacts of heat waves using Climate Change Indexes on the physiological and productive responses of lactating Holstein cows. Daily data of maximum and minimum air temperature for 1981-2021 were used. Heat waves were determined using six Climate Change Indexes. Individual data on respiratory rate, rectal temperature, and milk yield were collected in the summers of 2018, 2019, and 2021. The temperature trend analysis showed a significant (p < 0.0001) increase in maximum temperature, minimum temperature, and days in a heat wave. All six indexes increased significantly (p > 0.01). The increase in warm nights (> 20 °C) and the hottest days (> 35 °C) was the highest since 2010. Heat waves were classified into short (< 5 days) and long (> 5 days) of greater (> 36 °C) or lesser (< 36 °C) intensity. During the long and short heat waves of greater intensity, the respiratory rate increased (p < 0.05) until the fourth day. On the other hand, rectal temperature was higher (p < 0.05) from the fourth day until the end of the long heat waves. Therefore, the decrease in milk yield was significantly greater from the fourth or fifth day onwards. Finally, the evaluation method based on indexes was efficient to demonstrate the negative effects on physiological parameters and milk yield and can be indicated to evaluate heat stress in lactating cows.

Effect of Heat Waves on Some Italian Brown Swiss Dairy Cows' Production Patterns

Climate change is impacting worldwide efficiency and welfare standards in livestock production systems. Considering the sensibility to heat stress reported for different milk production patterns in Italian Brown Swiss, this study aims to evaluate the effect of heat waves (HWs)of different lengths on some milk production traits (fat-corrected milk, energy-corrected milk, protein and fat yield, protein percentage, cheese production at 24 h, and cheese yield). A 10-year dataset (2009–2018), containing 202,776 test-day records from 23,296 Brown Swiss cows, was used. The dataset was merged both with the daily maximum temperature–humidity index (THI) recorded by weather stations and with the daily maximum THI threshold for each trait in Italian Brown Swiss cows. The study considered 4 different HWs according to their length: 2, 3, 4, and 5 consecutive days before the test-day over the weighted THI threshold. Milk production traits were determined as the difference in losses compared to those after only 1 day before the test-day over the weighted maximum THI. All traits showed to be affected by HWs. Particularly, protein percentage losses increased from −0.047% to −0.070% after 2 consecutive days over the daily THI threshold, reaching −0.10% to −0.14% after 5 days (p &lt; 0.01), showing a worsening trend with the increasing length of HWs. First parity cows showed to be more sensitive to HWs than other parity classes, recording greater losses after shorter HWs, compared to multiparous cows, for protein yield and, consequently, for cheese production at 24 h. This suggests a less efficient metabolic response to heat stress and exposure time in primiparous, compared to multiparous cows, probably due to their incomplete growth process that overlaps milk production, making it more difficult for them to dissipate heat. Although actions to mitigate heat stress are always needed in livestock, this study points out that often time exposure to warm periods worsens milk production traits in Brown Swiss cows.

Climate Change and Livestock Production: A Literature Review

Globally, the climate is changing, and this has implications for livestock. Climate affects livestock growth rates, milk and egg production, reproductive performance, morbidity, and mortality, along with feed supply. Simultaneously, livestock is a climate change driver, generating 14.5% of total anthropogenic Greenhouse Gas (GHG) emissions. Herein, we review the literature addressing climate change and livestock, covering impacts, emissions, adaptation possibilities, and mitigation strategies. While the existing literature principally focuses on ruminants, we extended the scope to include non-ruminants. We found that livestock are affected by climate change and do enhance climate change through emissions but that there are adaptation and mitigation actions that can limit the effects of climate change. We also suggest some research directions and especially find the need for work in developing country settings. In the context of climate change, adaptation measures are pivotal to sustaining the growing demand for livestock products, but often their relevance depends on local conditions. Furthermore, mitigation is key to limiting the future extent of climate change and there are a number of possible strategies.

Congenital anomalies associated with ambient temperature variability during fetal organogenesis period of pregnancy: Evidence from 4.78 million births

BACKGROUNDS

Evidence for the effects of temperature variability on risk of congenital anomalies is lacking. We aimed to examine the association of temperature variability during fetal organogenesis period (weeks 3-8 post-conception) with major congenital anomalies.

METHODS

A retrospective cohort study comprising 4,787,356 singleton live-births and stillbirths in China was performed. We defined two temperature variability indices within gestational week i: the standard deviation (SD) of daily temperature (TVSD_i) and the maximum day-to-day temperature difference (TVD_i). At 6-week long timescales, we computed the SD of daily temperature (TVSD_3-8) and the average value of TVD_i (TVD_3-8). We matched two temperature variability indices, pollutant exposure levels over entire exposure window and data of each mother-infant pairs. An extended generalized estimating equation log-binomial regression model was constructed to explore their associations after adjusting for individual characters, temperature extremes and air pollutants. Stratified and sensitivity analyses were also performed.

RESULTS

59,571 neonates were registered as major congenital anomalies besides genetic and chromosomal anomalies. At weekly levels, the highest risk estimates of two temperature variability indices occurred at the 5th week for most anomaly groups. All TVSD₅, TVD₅, and maximum weekly TVSD and TVD were significantly associated with all anomaly groups; with the increment of 1 °C, the estimated risk ratio (RR) and corresponding 95% confidence interval (CI) ranges from 1.03 (1.01-1.05) to 1.19 (1.08-1.31). At 6-week scales, TVSD_3-8 and TVD_3-8 were associated with most anomaly subgroups. Overall, the strongest associations were estimated for isolated defects among morphology subgroups and cardiac defects among type subgroups.

CONCLUSIONS

Exposure to temperature variability during fetal organogenesis period of pregnancy is associated with increased risk of major congenital defects. Our findings provide a research foundation for public health policies, and further mechanism investigation.

Comparison and estimation of different linear and nonlinear lactation curve submodels in random regression analyses on dairy cattle

In the random regression model (RRM) for milk yield, by replacing empirical lactation curves with the five-order Legendre polynomial to fit fixed groups, the RRM can be transformed to a hierarchical model that consisted of a RRM in the first hierarchy with Legendre polynomials as individuals’ lactation curves resolved by restricted maximum likelihood (REML) software, and a multivariate animal model for phenotypic regression coefficients in the second hierarchy resolved by DMU software. Some empirical lactation functions can be embedded into the RRM at the first hierarchy to well fit phenotypic lactation curve of the average observations across all animals. The functional relationship between each parameter and time can be described by a Legendre polynomial or an empirical curve usually called submodel, and according to three commonly used criteria, the optimal submodels were picked from linear and nonlinear submodels except for polynomials. The so-called hierarchical estimation for the RRMs in dairy cattle indicated that more biologically meaningful models were available to fit the lactation curves; moreover, with the same number of parameters, the empirical lactation curves (MIL1, MIL5, and MK1 for 3, 4, and 5 parameters, respectively) performed higher goodness of fit than Legendre polynomial when modelling individuals’ phenotypic lactation curves.

Modification of the effects of nitrogen dioxide and sulfur dioxide on congenital limb defects by meteorological conditions

STUDY QUESTION

Can meteorological conditions modify the associations between NO2 and SO2 exposure and congenital limb defects (CLDs) during the first trimester of pregnancy?

SUMMARY ANSWER

Increases in NO2 and SO2 exposure were consistently associated with higher risks of CLDs during the first trimester of pregnancy; both low- and high-temperature exposure and high air humidity act synergistically with the two air pollutants on CLDs.

WHAT IS KNOWN ALREADY

Animal studies have indicated air pollutants are associated with CLDs, but corresponding epidemiological studies are limited with equivocal conclusions. Meteorological conditions are closely connected to the generation, diffusion, distribution and even chemical toxicity of air pollutants.

STUDY DESIGN, SIZE, DURATION

This case-control study included 972 cases of CLDs and 9720 controls in Changsha, China during 2015-2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Cases from the hospital based monitoring system for birth defects (including polydactyly, syndactyly, limb shortening, and clubfoot) and healthy controls from the electronic medical records system were studied. Complete data on daily average NO2 and SO2 concentrations and meteorological variables were obtained from local monitoring stations to estimate monthly individual exposures during the first trimester of pregnancy, using the nearest monitoring station approach for NO2 and SO2 concentrations, and the city-wide average approach for temperature and relative humidity, respectively. The 25th and 75th percentiles of daily mean temperature, as well as the 50th percentile of daily mean relative humidity during the study period were used to classify high- and low-temperature exposure, and high humidity exposure based on existing evidence and local climate characteristics. Multivariate logistic regression models were used to estimate the independent effects per 10 μg/m3 increase in NO2 and SO2 on CLDs, and the attribute proportions of interaction (API) were used to quantify the additive joint effects of air pollutants with meteorological conditions after including a cross product interaction term in the regression models.

MAIN RESULTS AND THE ROLE OF CHANCE

NO2 and SO2 exposures during the first trimester of pregnancy were consistently and positively associated with overall CLDs and subtypes, with adjusted odd ratios (aORs) ranging from 1.13 to 1.27 for NO2, and from 1.37 to 2.49 for SO2. The effect estimates were generally observed to be the strongest in the first month and then attenuated in the second and third months of pregnancy. Synergistic effects of both low and high temperature in combination with NO2 (with APIs ranging from 0.07 to 0.38) and SO2 (with APIs ranging from 0.18 to 0.51) appeared in the first trimester of pregnancy. Several significant modifying effects by high humidity were also observed, especially for SO2 (with APIs ranging from 0.13 to 0.38). Neither NO2 nor SO2 showed an interactive effect with season of conception.

LIMITATIONS, REASONS FOR CAUTION

The methods used to estimate individual exposure levels of air pollutants and meteorological factors may lead to the misclassification bias because of the lack of information on maternal activity patterns and residential mobility during pregnancy. Moreover, we were unable to consider several potentially confounding factors, including socioeconomic status, maternal nutrient levels, alcohol use and smoking during early pregnancy due to unavailable data, although previous studies have suggested limited change to the results after when including these factors in the analysis.

WIDER IMPLICATIONS OF THE FINDINGS

The findings are helpful for understanding the combined effects of air pollution and meteorological conditions on birth defects. Environmental policies and practices should be formulated and implemented to decrease air pollutant emissions and improve meteorological conditions to reduce their harmful effects on pregnancy. Additionally, pregnant women should be suggested to reduce outdoor time when the air quality is poor, especially when ambient temperature is higher or lower than what is comfortable, or when it is excessively humid.

STUDY FUNDING/COMPETING INTEREST(S)

The study is funded by Major Scientific and Technological Projects for Collaborative Prevention and Control of Birth Defects in Hunan Province (2019SK1012), Major Research and Development Projects in Hunan Province (2018SK2060) and Scientific and Technological Department Projects in Hunan Province (2017SK50802). There are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

The Role of Innate Immune Response and Microbiome in Resilience of Dairy Cattle to Disease: The Mastitis Model

Animal health is affected by many factors such as metabolic stress, the immune system, and epidemiological features that interconnect. The immune system has evolved along with the phylogenetic evolution as a highly refined sensing and response system, poised to react against diverse infectious and non-infectious stressors for better survival and adaptation. It is now known that high genetic merit for milk yield is correlated with a defective control of the inflammatory response, underlying the occurrence of several production diseases. This is evident in the mastitis model where high-yielding dairy cows show high disease prevalence of the mammary gland with reduced effectiveness of the innate immune system and poor control over the inflammatory response to microbial agents. There is growing evidence of epigenetic effects on innate immunity genes underlying the response to common microbial agents. The aforementioned agents, along with other non-infectious stressors, can give rise to abnormal activation of the innate immune system, underlying serious disease conditions, and affecting milk yield. Furthermore, the microbiome also plays a role in shaping immune functions and disease resistance as a whole. Accordingly, proper modulation of the microbiome can be pivotal to successful disease control strategies. These strategies can benefit from a fundamental re-appraisal of native cattle breeds as models of disease resistance based on successful coping of both infectious and non-infectious stressors.

Heat load increases the risk of clinical mastitis in dairy cattle

The study was aimed at assessing heat load-related risk of clinical mastitis (CM) in dairy cows. Records of CM for the years 2014 and 2015 were obtained from a large conventional dairy farm milking about 1,200 Holstein cows in central Italy. A case of CM was defined by the presence of clinical signs and veterinary confirmation. Quarter milk samples were collected and bacteriological investigated for each CM. Etiological agents were identified and classified as environmental or contagious pathogens. Hourly weather data from the nearest weather station were used to calculate heat load index (HLI). Upper and lower thresholds of HLI, at which the animal accumulates or dissipates heat, were settled and used to measure heat load balance through the accumulated heat load (AHL) model. Zero and positive values of AHL indicate periods of thermo-neutral and heat accumulation, respectively. Each case of CM was associated with HLI-AHL values recorded 5 d before the event. The risk of CM was evaluated using a case-crossover design. A conditional logistic regression model was used to calculate the odds ratio and 95% confidence intervals of CM recorded in thermo-neutral (AHL = 0) or heat load (AHL > 0) days, pooled or stratified for pathogen type (environmental or contagious). Classes of AHL as low (<6.5), medium (6.6-34.9), and high (>35) were included in the model. Other variables included in the model were milk yield as liters (<20, 20-30, and >30), days in milk (<60, 60-150, and >150), and parity (1, 2-3, and >3). A total of 1,086 CM cases were identified from 677 cows. Escherichia coli, Streptococcus spp., and Streptococcus uberis were the environmental pathogens isolated with the highest frequency; Staphylococcus aureus prevailed within contagious species. The analysis of pooled data indicated a significant effect of heat load on the occurrence of CM in the contagious pathogen stratum. Higher milk yield, middle and late stage of lactation, and older parity increased the risk of CM under heat load conditions. However, the association between pathogen type and these factors was not clear because the model provided significant odds ratios within all pathogen categories. The present study provided the first evidence of an association between HLI and CM in dairy cattle and suggested the ability of the AHL model to assess the risk of mastitis associated with heat load.

Prospects for gene introgression or gene editing as a strategy for reduction of the impact of heat stress on production and reproduction in cattle

In cattle, genetic variation exists in regulation of body temperature and stabilization of cellular function during heat stress. There are opportunities to reduce the impact of heat stress on cattle production by identifying the causative mutations responsible for genetic variation in thermotolerance and transferring specific alleles that confer thermotolerance to breeds not adapted to hot climates. An example of a mutation conferring superior ability to regulate body temperature is the group of frame-sift mutations in the prolactin receptor gene (PRLR) that lead to a truncated receptor and development of cattle with a short, sleek hair coat. Slick mutations in PRLR have been found in several extant breeds derived from criollo cattle. The slick mutation in Senepol cattle has been introgressed into dairy cattle in Puerto Rico, Florida and New Zealand. An example of a mutation that confers cellular protection against elevated body temperature is a deletion mutation in the promoter region of a heat shock protein 70 gene called HSPA1L. Inheritance of the mutation results in amplification of the transcriptional response of HSPA1L to heat shock and increased cell survival. The case of PRLR provides a promising example of the efficacy of the genetic approach outlined in this paper. Identification of other mutations conferring thermotolerance at the whole-animal or cellular level will lead to additional opportunities for using genetic solutions to reduce the impact of heat stress.

Impact of global climate change on livestock health: Bangladesh perspective

The global carbon emission rate, due to energy-driven consumption of fossil fuels and anthropogenic activities, is higher at any point in mankind history, disrupting the global carbon cycle and contributing to a major cause of warming of the planet with air and ocean temperatures, which is rising dangerously over the past century. Climate change presents challenges both direct and indirect for livestock production and health. With more frequent extreme weather events including increased temperatures, livestock health is greatly affected by resulting heat stress, metabolic disorder, oxidative stress, and immune suppression, resulting in an increased propensity for disease incidence and death. The indirect health effects relate to the multiplication and distribution of parasites, reproduction, virulence, and transmission of infectious pathogens and/or their vectors. Managing the growing crossbreeding livestock industry in Bangladesh is also at the coalface for the emerging impacts of climate change, with unknown consequences for the incidence of emerging and re-emerging diseases. Bangladesh is now one of the most vulnerable nations to global climate change. The livestock sector is considered as a major part of food security for Bangladesh, alongside agriculture, and with one of the world’s largest growing economies, the impacts are exaggerated with this disaster. There has been no direct study conducted on the impact of climate change on livestock health and the diseases in Bangladesh. This review looks to explore the linkage between climate change and livestock health and provide some guidelines to combat the impact on livestock from the Bangladesh perspective.

Thermoregulatory Responses of Heat Acclimatized Buffaloes to Simulated Heat Waves

Climate change is seen as a significant threat to the sustainability of livestock production systems in many parts of the world, particularly in tropical regions. Extreme meteorological events can result in catastrophic production and death of livestock. Heat waves in particular can push vulnerable animals beyond their survival threshold limits. However, there is little information about buffalo responses to sudden changes in the thermal environment, specifically the heat waves. This study aimed to quantify the thermoregulatory and blood biochemical responses of heat-acclimatized buffaloes to a simulated heat wave. The experiment was designed in a climatic chamber with two periods of 4 days each. Twelve heat acclimated buffalo heifers aged 18 months were used. The climatic chamber environment was set as follows: 4-day period (P1) simulating the same weather conditions of a summer in humid tropical climate used as a baseline, with daily cycle with Ta and RH at 27 ± 1 °C and 76% from 0600 h to 1900 h and 24 ± 1 °C and 80% from 1900 h to 0600 h, and 4-day period (P2), simulating a daily heat wave cycle, from 0600 h to 1900 h with Ta and RH kept at 36 °C and 78% and from 1900 h to 0600 h, 27 °C and 74%. All animals were subject to both treatments and data were analyzed by a repeated measure analysis of variance, with post-hoc pooling comparison performed by Tukey's test. In P2, there was observed a significant increase in respiratory frequency (p < 0.01), found four times in P1. The sweating rates were quite high in both periods; still, there were significant increases in P2 compared to P1 (p < 0.01) (4931 and 3201 g/m²/h, respectively). A slight but significant increase in rectal temperature was observed during the day (p < 0.01), with a rising until 1900 h. The simulated heat wave in P2 did not affect the values of the erythrogram or leukogram, excluding the significant reduction in K⁺ (p < 0.05). The low heat storage and the subsequent fast and full recovery of the thermal balance late afternoon appear to be related to the high sweating rate values. The massive sweating rate emphasizes its relevance in the maintenance of buffalo homeothermy. The absence of changes in hematological parameters has revealed the considerable physiological resilience of buffaloes toward simulated heat waves.

Effect of evaporative cooling and altitude on dairy cows milk efficiency in lowlands

The objective of this current work was to determinate the effect of high temperatures on milk production of dairy cows in southern Slovakia in the year 2015. The hypotheses that milk production is influenced by the altitude and cooling were tested. Production data included 227,500 test-day records belonging to 34 Holstein breed herds situated in lowlands, 115 to 150 m above sea level (ASL) and kept in free-stall housing. Dairy farms were classified into groups based on cooling system. The first group of cows (19 herds) was cooled evaporative (foggers) and forced ventilation, and the second group (15 herds) was using cooled only forced ventilation (automatically controlled fans in housing and feeding areas). During the period from May to September, 36 summer and 22 tropical days were recorded, 37 days had a mean thermal humidity index value above 72.0, and on 34 days we recorded mean values above 78.0. The highest milk yields were recorded at the altitude 1 (115 m ASL) (9219.0 kg year^-1; 10327.0 kg year^-1) and the lowest at the altitude 2 (126 m ASL) (7598.7 kg year^-1; 8470.21 kg year^-1) (P < 0.001). Dairy cows cooled evaporative milked significantly more milk than cows cooled only with forced air flow (9650.4 kg vs. 8528.0 kg; P < 0.001). Fat and protein production differed also significantly (364.0 kg vs. 329.5 kg, P < 0.001; 312.2 kg vs. 279.7 kg, P < 0.001). It can be concluded that not only heat stress but also location farm above sea level can affect milk production. Evaporative cooling associated with increased air velocity is the appropriate protection against high temperatures.

Effects of Climatic Conditions on the Lying Behavior of a Group of Primiparous Dairy Cows

Currently, lying behavior can be assessed using continuous observations from sensors (e.g., accelerometers). The analysis of digital data deriving from accelerometers is an effective tool for studying livestock behaviors. Despite the large interest in the lying behavior of dairy cows, no reference was found in literature regarding the prediction of lying behavior as a function of the interaction of environmental parameters. The present study aimed to evaluate the influence of climatic conditions (temperature-humidity index, solar radiation, air velocity and rainfalls) on the lying behavior of a group of primiparous dairy cows, using data from accelerometers, and develop a prediction model to identify and predict the lying behavior of dairy cows as a function of the effects of environmental conditions. Results from the. GLM Procedure (SAS) showed that the model was highly significant (p < 0.001) and the r2 was 0.84. All of the effects in the model resulted in being highly significant (p < 0.001). This model, if validated properly, could be a valid early warning system to identify any deviation from the expected behavior, and to assess the effectiveness of thermal stress mitigation strategies.

Dados de estação meteorológica oficial subestimam o estresse por calor em bovinos leiteiros criados em ambiente tropical

RESUMO Determinaram-se os valores de temperatura do ar, umidade relativa e índice de temperatura e umidade (ITU) de uma propriedade rural de produção de leite a pasto e da estação meteorológica oficial mais próxima, confrontando-os. Na fazenda, as leituras dos dados foram registradas por uma estação meteorológica automática, a cada cinco minutos, de fevereiro de 2015 a setembro de 2016. Depois, calcularam-se a média por hora e o ITU horário. Selecionaram-se os valores diários mínimo, médio e máximo. O mesmo foi feito com os dados da estação meteorológica oficial, que foram horários. As temperaturas mínima e média na estação meteorológica foram maiores que na fazenda durante todo o período experimental e em 16 meses, respectivamente. A temperatura máxima da propriedade rural foi maior que a da estação em seis meses. Já a umidade relativa mínima, a média e a máxima da estação meteorológica foram inferiores às da fazenda. O ITU mínimo foi maior na estação oficial e o ITU máximo superior na fazenda em todos os meses. Por fim, o número de dias com um ITU máximo igual ou superior ao ITU crítico foi maior na fazenda. Assim, dados da estação meteorológica oficial subestimam o estresse por calor.

Short-term effects of air pollution and temperature on cattle mortality in the Netherlands

BACKGROUND

Extreme temperatures and air pollution are both associated with increased mortality risk in humans. However, the effects of temperature and air pollution on cattle have not been investigated much before.

OBJECTIVES

Short-term effects of temperature (heat and cold) and air pollution on cattle mortality were investigated and quantified in the Netherlands during 2012-2017.

METHODS

Daily data on cattle mortality, weather conditions and mean levels of particulate matter (PM₁₀), ozone (O₃), ammonia (NH₃) and nitrogen dioxide (NO₂) of the Netherlands during 2012-2017 were collected. Associations were investigated with time-series regression using distributed lag non-linear models including lags of up to 25 days. Effects of temperature were expressed as those associated with extreme and moderate heat or cold, defined as Temperature Humidity Index (THI) values below the 1st and 5th percentile, and above the 95th and 99th percentile of the national THI distribution. Effects of air pollutants were expressed per 10 μg/m³ change in daily mean concentrations.

RESULTS

Both high and low temperatures were associated with increased mortality amongst different age groups. For instance, the newborn calves of at most 14 days showed a cumulative relative risk (RR) of 2.13 (95%CI: 1.99-2.28) for extreme heat and the pre-weaned calves (15-55 days) showed a cumulative RR of 1.50 (95%CI: 1.37-1.64) for extreme cold. Associations of air pollution with mortality were not consistent, except for the effect of ozone of lag 0-7 and lag 0-25. Exposure to O₃ in the newborn calves resulted in a cumulative RR of 1.09 (95%CI: 1.04-1.4) for lag 0-7 and 1.09 (95%CI: 1.03-1.16) for lag 0-25.

CONCLUSIONS

Both high and low temperatures were associated with increased mortality amongst pre-weaned calves of 15-55 days, whereas associations in weaned calves (56 days - 1 year) were only observed for low temperatures and in newborn calves of at most 14 days and lactating cattle >2 years only for high temperatures. Associations of air pollution with mortality in all age groups were not consistent, except for the effect of ozone of lag 0-7 and lag 0-25.

Spatially explicit estimation of heat stress-related impacts of climate change on the milk production of dairy cows in the United Kingdom

Dairy farming is one the most important sectors of United Kingdom (UK) agriculture. It faces major challenges due to climate change, which will have direct impacts on dairy cows as a result of heat stress. In the absence of adaptations, this could potentially lead to considerable milk loss. Using an 11-member climate projection ensemble, as well as an ensemble of 18 milk loss estimation methods, temporal changes in milk production of UK dairy cows were estimated for the 21st century at a 25 km resolution in a spatially-explicit way. While increases in UK temperatures are projected to lead to relatively low average annual milk losses, even for southern UK regions (<180 kg/cow), the ‘hottest’ 25×25 km grid cell in the hottest year in the 2090s, showed an annual milk loss exceeding 1300 kg/cow. This figure represents approximately 17% of the potential milk production of today’s average cow. Despite the potential considerable inter-annual variability of annual milk loss, as well as the large differences between the climate projections, the variety of calculation methods is likely to introduce even greater uncertainty into milk loss estimations. To address this issue, a novel, more biologically-appropriate mechanism of estimating milk loss is proposed that provides more realistic future projections. We conclude that South West England is the region most vulnerable to climate change economically, because it is characterised by a high dairy herd density and therefore potentially high heat stress-related milk loss. In the absence of mitigation measures, estimated heat stress-related annual income loss for this region by the end of this century may reach £13.4M in average years and £33.8M in extreme years.

Comparative transcriptional profiling analysis of the effect of heat waves during embryo incubation on the hatchlings of the Chinese soft-shelled turtle (Pelodiscus sinensis)

Temperature is one of most the important environmental factors that affect the ontogenesis of organisms. In this study, we incubated Chinese soft‐shelled turtle eggs at 28°C (control temperature, C treatment), a temperature with a 16°C cold shock and a 36°C heat shock twice per week (S treatment) or a ramp‐programmed temperature of 29 ± 9°C (with 12 hr (+) and 12 hr (−) every day) (F treatment). The incubation period, hatching success, hatchling weight, and locomotor performance were significantly different between the controls and the different heat treatment groups. The pathogen challenge results illustrated that hatchlings from the S treatment group were more resistant to bacterial infection, whereas hatchlings from the F treatment group were more vulnerable. We used RNA‐seq quantification analysis to identify differentially expressed genes (DEGs) of hatchlings in the S treatment group. Based on the functional annotation results for the DEGs, 9 genes were chosen to verify the RNA‐seq results. The background expression of DEGs was also analyzed for the three treatments, as was the regulation of the pathogen challenge. The results showed that 8 DEGs were related to the immune response after pathogen challenge and that temperature was an important factor in differential regulation of the immunity pathways.

On-farm deaths of dairy cows are associated with features of freestall barns

On-farm death (OFD) of a dairy cow is always a financial loss for a farmer, and potentially a welfare issue that has to be addressed within the dairy industry. The aim of this study was to explore the associations between OFD of dairy cows, housing, and herd management in freestall barns. To achieve the goal, we followed 10,837 cows calving in 2011 in 82 herds. Data were gathered with observations and a structured interview during farm visits and from a national dairy herd improvement database. The hazard of OFD was modeled with a shared frailty survival model, with SAS 9.3 PHREG procedure (SAS Institute Inc., Cary, NC). The study population was 58% Ayrshire and 42% Holstein cows. The median herd size and mean milk yield in the study herds were 116 cows and 9,151 kg of milk per cow per year. The overall probability of OFD was 6.0%; 1.8% of the cows died unassisted and 4.2% were euthanized. Variation in OFD percentage between individual herds was large, from 0 to 16%, accounting for 0 to 58% of all removals in the herds. Keeping close-up dry cows in their own group was associated with higher hazard of OFD [hazard ratio (HR) = 1.37] compared with keeping them in the same pen with far-off dry cows. Higher hazard on OFD was observed when barns had only one kind of calving pen; single (HR = 2.09) or group pens (HR = 1.72), compared with having both of those types. The hazard of OFD was lower if the whole herd was housed in barns or pens that had only 1 type of feed barrier at the feed bunk, namely post-and-rail (HR = 0.51) or a type with barriers between the cow's heads (HR = 0.49), compared with having 2 types. Lower OFD hazard was observed with wider than 340 cm of walking alley next to the feeding table (HR = 0.75), and with housing a whole herd in pens with only 1 type of walking alley surface, specifically slatted (HR = 0.53) or solid (HR = 0.48), compared with having both types. The hazard of OFD was higher with stalls wider than 120 cm (HR = 1.38) compared with narrower stalls. The hazard of OFD was also associated with breed, parity, and calving season. This study identified many factors that contribute to the incidence of OFD of dairy cows. The solutions for reducing on-farm mortality include housing, management, and breeding choices that are most probably herd specific.

Effect of hot season on blood parameters, fecal fermentative parameters, and occurrence of Clostridium tyrobutyricum spores in feces of lactating dairy cows

High temperature influences rumen and gut health, passage rate, and diet digestibility, with effects on fermentative processes. The main aim of the study was to investigate the effect of hot season on hindgut fermentation, the occurrence of Clostridium tyrobutyricum spores in bovine feces, and on their relationship with metabolic conditions in dairy cows producing milk used for Grana Padano cheese. The study was carried out on 7 dairy farms located in the Po Valley (Italy), involving 1,950 Italian Friesian dairy cows. The study was carried out from November 2013 till the end of July 2014. Temperature and relative humidity were recorded daily by weather stations. Constant management conditions were maintained during the experimental period. Feed and diet characteristics, metabolic conditions, and fecal characteristics were recorded in winter (from late November 2013 to the end of January 2014), spring (from April to May 2014), and summer (July 2014) season. In each season, blood samples were collected from 14 multiparous lactating dairy cows per herd to measure biochemical indices related to energy, protein, and mineral metabolism, as well as markers of inflammation and some enzyme activities. Fecal samples were also collected and measurements of moisture, pH and volatile fatty acids (VFA) were performed. The DNA extracted and purified from fecal samples was used to detect Clostridium tyrobutyricum spores in a quantitative real-time PCR assay. The daily mean temperature-humidity index was 40.7 ± 4.6 (range 25 to 55), 61.2 ± 3.7 (range 39 to 77), and 70.8 ± 3.2 (range 54 to 83) in winter, spring, and summer, respectively. Total VFA concentration in feces progressively decreased from winter to summer. The seasonal changes of acetate and propionate followed the same trend of total VFA; conversely, butyrate did not show any difference between seasons, and its molar proportion was greater in summer compared with winter. A greater occurrence of Cl. tyrobutyricum spores in summer compared with the other seasons was observed. The plasma concentrations of glucose, urea, albumin, Ca, Mg, Cl, Zn, and alkaline phosphatase activity were lower in summer compared with winter, whereas the opposite occurred for bilirubin and Na. Our results show that summer season, through direct and indirect effect of heat stress, affected fecal fermentative parameters and hindgut buffering capacity, and was responsible for the increasing occurrence of Cl. tyrobutyricum spores in feces.

Challenges and priorities for modelling livestock health and pathogens in the context of climate change

Climate change has the potential to impair livestock health, with consequences for animal welfare, productivity, greenhouse gas emissions, and human livelihoods and health. Modelling has an important role in assessing the impacts of climate change on livestock systems and the efficacy of potential adaptation strategies, to support decision making for more efficient, resilient and sustainable production. However, a coherent set of challenges and research priorities for modelling livestock health and pathogens under climate change has not previously been available. To identify such challenges and priorities, researchers from across Europe were engaged in a horizon-scanning study, involving workshop and questionnaire based exercises and focussed literature reviews. Eighteen key challenges were identified and grouped into six categories based on subject-specific and capacity building requirements. Across a number of challenges, the need for inventories relating model types to different applications (e.g. the pathogen species, region, scale of focus and purpose to which they can be applied) was identified, in order to identify gaps in capability in relation to the impacts of climate change on animal health. The need for collaboration and learning across disciplines was highlighted in several challenges, e.g. to better understand and model complex ecological interactions between pathogens, vectors, wildlife hosts and livestock in the context of climate change. Collaboration between socio-economic and biophysical disciplines was seen as important for better engagement with stakeholders and for improved modelling of the costs and benefits of poor livestock health. The need for more comprehensive validation of empirical relationships, for harmonising terminology and measurements, and for building capacity for under-researched nations, systems and health problems indicated the importance of joined up approaches across nations. The challenges and priorities identified can help focus the development of modelling capacity and future research structures in this vital field. Well-funded networks capable of managing the long-term development of shared resources are required in order to create a cohesive modelling community equipped to tackle the complex challenges of climate change.