This study evaluates the effect of heat stress on milk production and describes the pattern of response of milk yield to increasing heat load, using temperature-humidity index (THI) on test-day milk records of small holder dairy cattle herds in the sub-Saharan African climate of Tanzania. Climate data obtained from aWhere, an agricultural weather data platform (http://www.awhere.com) was analysed with 14,367 first lactation test day milk records of 3511 dairy cows collected between 2016 and 2019. THI was calculated from daily maximal temperatures and daily minimum humidity. Three sets of analysis were performed. In the first and second analysis, two mixed effect repeatability models were fitted with THI treated as a categorical variable grouped into 5 classes (THI1= [61 - 66], THI2= [67 - 71], THI3= [72 - 78], THI4=[79 - 81], THI5=[82 - 86]), to obtain least squares estimates of THI effect on milk production, and as a continuous variable within THI classes to identify THI thresholds at which milk yield started to decline. In the third analyses, one quadratic polynomial regression (POL) and three regression spline functions namely piecewise linear spline function (PLF), natural splines function (NSF) and cubic splines function (CSF) were fitted to determine the average effect of THI on milk yield in the population and describe the pattern of response of milk yield to increasing head load. The results show that heat stress reduced milk yield by 4.16% to 14.42% across THI groups, with daily milk yield being the highest in THI1 (7.40±0.39 litres) and the lowest in THI4 (6.33±0.32). Regression coefficients within groups showed significant daily milk yield decrease in THI2 (-0.09) and THI3 (-0.06), but not for other THI classes, indicating that cows experienced heat stress between THI values of 67 and 76 and milk loss plateaued afterwards, suggesting that the animals acclimatized to heat stress conditions beyond THI value of 76. At the population level, THI and its squared term were significantly negatively and positively (-0.61, 0.004) associated with milk production, indicating a non-linear relationship between milk yield and THI. The CSF model showed better goodness of fit and predictive ability than other models for predicting future population response of milk yield to heat stress in small holder dairy farms in Tanzania. Herd management strategies and animal husbandry measures are needed in small holder dairy farms in Tanzania to minimize the impact of heat stress on milk yield and income of the farmers.

To determine the influence of maternal nutrient restriction and rumen-protected arginine supplementation on post-ruminal digestive enzyme activity in lambs, 31 multiparous, Rambouillet ewes were allocated to one of three dietary treatments at 54 d of gestation. Dietary treatments were 100% of nutrient requirements (control, CON; n = 11), 60% of control (restricted, RES; n = 10), or RES plus 180 mg rumen-protected arginine•kg BW•d (RES-ARG; n = 10). Immediately after parturition, lambs were removed from dams and reared independently. Milk-replacer and alfalfa hay + creep feed were offered for intake. At day 54 of age, lambs were slaughtered and the pancreas and small intestine were collected. Pancreatic (α-amylase and trypsin) and jejunal (maltase, glucoamylase, sucrase, isomaltase, and lactase) digestive enzyme activities were assayed. Data were analyzed using the GLM procedure of SAS for effects of treatment. Contrast statements were used to determine differences between means for effects of restriction (CON vs. RES and RES-ARG) and rumen-protected arginine supplementation (RES vs. RES-ARG). There was no influence ( ≥ 0.15) of maternal nutrient restriction or rumen-protected arginine supplementation on pancreatic or jejunal protein concentrations. No treatment effects were observed ( ≥ 0.12) for enzymes involved in starch digestion including pancreatic α-amylase and jejunal maltase, glucoamylase, and isomaltase. Sucrase activity was undetected in the jejunum of lambs across all treatments. Maternal nutrient restriction tended to increase ( = 0.08) pancreatic trypsin activity per gram protein in lambs. Lactase activity per gram protein in the jejunum of lambs tended to decrease ( = 0.09) with maternal nutrient restriction. Rumen-protected arginine supplementation to gestating ewes did not influence ( ≥ 0.19) digestive enzyme activities of lamb offspring. These data suggest that maternal nutrient restriction and rumen-protected arginine supplementation have minimal effects on digestive enzyme activity in offspring.

The aim of this study was to determine the effect of colostrum-supplemented transition milk on the growth rate of newborn calves. Thirty-six day-old female Holstein calves with a birth weight of 43.4 ± 5.5 kg were randomly assigned to a treatment group and a control group. On day 1, all calves received one portion (3 kg) of colostrum within 2 h after birth. Between the second feeding and the age of 5 days, control calves received only transition milk that had been collected from dams shortly before feeding, and the treatment group received 1.5 kg of colostrum collected from dams on day 1 and 1.5 kg of transition milk from subsequent milkings. Monthly body weight and average daily gain were used to measure growth performance. Blood samples were collected from the jugular vein at multiple time points to evaluate the biochemical and immune status of calves. Colostrum-supplemented transition milk increased the concentrations of serum immunoglobulins, triacylglycerols, cholesterol and total protein. The activity of lactate-dehydrogenase and ceruloplasmin decreased, whereas lysozyme activity increased with time in the control group. It can be concluded that additional five days of colostrum feeding positively influences non-specific humoral immunity indicators and serum biochemical parameters in dairy calves.

Small ruminants such as goats are an important source of income for smallholder farmers in South Asia and Sub Saharan Africa: they may be kept as a stepping stone to owning larger and higher-value animals such as cattle or buffalo, or provide a more-profitable and less-risky alternative in marginal or densely populated areas where access to feed resources are limited. However, smallholder goat production in these areas is often low due to low growth and reproduction rates and high animal mortality. The aim of this study was to investigate the potential for different intervention packages to increase yields and profitability of goat meat production in Ethiopia and India. Packages were based on improved nutrition, reduced flock mortality from improved control of health and diseases, and replacing indigenous livestock with improved goat breeds. Household modelling was used to simulate the effects of interventions on goat production and household income in the extensive lowland grazing zone and highland mixed crop-livestock zones of Ethiopia, and the extensive arid zone of India. Our analysis showed that there are opportunities to increase goat meat production in both countries. Reproduction, liveweight gain and survival rates can be increased through better nutrition, genetics and healthcare, but the biggest increase in production and profits occurred when multiple interventions were combined. Importantly, interventions resulting in the biggest increases in goat meat production or number of animals sold did not always give the highest profits.

Neonatal calf diarrhoea can have important economic consequences. Scour vaccines are available against some of the most frequent pathogens responsible for this disease: Bovine Rotavirus (BoRV), Bovine Coronavirus (BoCV) and K99. In this multi-centre, randomised, blinded study, adult cows vaccinated with a trivalent vaccine marketed for years (Rotavec™ Corona, MSD Animal Health - RC) prior to last parturition were revaccinated 12-15 months later, prior to the upcoming parturition, with either a single injection of a recently marketed vaccine (Bovigen™ Scour, Virbac - BS), or RC. The aim of this trial was to verify whether BS is not inferior to RC for the stimulation of the immune response and the passive transfer to calves in these conditions. A total of 136 multiparous dairy cows, from 5 different herds and located in 3 countries (France, UK and Germany) were enrolled in the study. Sixty-five cows were vaccinated with BS and 71 with RC. Antibody levels, measured by competitive ELISA and represented as percentage of inhibition (PI), were assessed in the cow's serum (on the day of vaccination: D0 and on days 21, 42 and at calving), in the colostrum and in the serum of calves in the first week of life. Differences in means of PI between groups and the 95% confidence interval (CI) were calculated. The non-inferiority threshold was set at -10%. The relationships between antibody levels in the colostrum and the vaccination-calving interval (VCI) or the inter-booster vaccination interval (IBVI) were also analysed. All the lower margins of the 95% CI of the difference in means of PI, in all samples and for the 3 pathogens assessed, were above -10%. This result shows that BS is not inferior to RC for the stimulation of the immune response against BoRV, BoCV and K99 and the passive transfer of immunity to calves when this vaccine is administered to their dams previously vaccinated with RC. Furthermore, no correlation was found between PI values in the colostrum and the VCI or IBVI. The ratio of animals with a PI ≥ 95% in the colostrum, among cows with similar intervals, was not significantly different between groups, for all antigens tested. Therefore, this study shows that a single injection of the heterologous vaccine BS can be used as a booster in cattle previously vaccinated with RC.

This study investigated abomasal luminal parameters in healthy and diarrheic calves by using a wireless ambulatory capsule (WAC). The acetaminophen absorption test (APAT) was used to determine abomasal emptying rate. Four healthy and five diarrheic female Holstein-Friesian calves (age < 14 days) were included in the study. For APAT, calves were fed 2 L of milk replacer containing 50 mg acetaminophen/kg body weight, and blood samples were taken during a 12-h period afterward. Concomitantly, a WAC in the abomasum continuously measured luminal pH, pressure, and temperature. Five hours post suckling, intraluminal temperature was significantly higher in diarrheic calves than in healthy calves. Abomasal pH and pressure were not significantly different, but intraluminal pressure was always numerically lower in diarrheic calves. During APAT no significant differences in maximum acetaminophen concentrations (C) and time to reach maximum acetaminophen concentration (T) were observed. Nonlinear regression findings revealed a longer acetaminophen half-time (AAP t) in diarrheic calves compared to healthy calves [564 ± 96 min vs. 393 ± 84 min, respectively; = 0.04] and lower area under the concentration curve values (e.g., 60 min postprandial AUC 681 ± 244 (µg∙min)/mL vs. 1064 ± 23 (µg∙min)/mL, respectively; = 0.04). In conclusion, abomasal luminal conditions were different between diarrheic and healthy calves. Significant differences in APAT reflected a delay in abomasal emptying in diarrheic calves. Impaired abomasal movement may induce enhanced bacterial fermentation processes as indicated by a higher abomasal temperature in diarrheic calves, which should be considered in management of their feeding.

Healthy, thriving calves are essential for beef calf production. We studied the health status and factors associated with the growth of beef calves in six cow-calf herds during the first month of the calves' lives and at weaning age (200 days). The six herds were visited three times, when calves were approximately 3 days, 16 days and 30 days of age. On each visit calves (n=37) were clinically examined, weighed or measured, blood samples were collected, faecal samples obtained and deep nasopharyngeal swabs were taken. Each blood sample was analysed for acute phase proteins (haptoglobin, serum amyloid-A, fibrinogen), total proteins and albumin, the faecal sample for intestinal tract pathogens (rotavirus, bovine coronavirus, enterotoxigenic and , oocysts of coccidia and , and nematode eggs), and the nasopharyngeal swab for respiratory tract pathogens (bovine coronavirus (BCV), respiratory syncytial virus (RSV), bacteria and mycoplasma). Clinical diagnosis of respiratory tract disease, diarrhoea or umbilical disease was set at 15.0% for all the three consecutive examinations combined (n=107), but only few pathogens were detected from the samples. The increased levels of acute phase proteins were neither associated with any of the diseases nor with the pathogens. Random intercept linear models were used to explore factors affecting early (3-30 days) and long-term (3-200 days) growth, showing that calves with elevated serum amyloid-A concentrations at the age of 16 days had lower long-term growth. Increased albumin concentration at 30 days of age and higher parity of the dam increased early-term growth. The lack of association between a disease and the acute phase protein may stem from the low disease prevalence in the beef calves examined. The measurement of acute phase proteins of a young calf can help identify animals with possible future growth deficiencies, although the mechanisms through which the association between acute phase proteins and growth has yet to be explained.

This paper considers the application of genetic and genomic techniques to disease resistance, the interpretation of data arising from such studies and the utilisation of the research outcomes to breed animals for enhanced resistance. Resistance and tolerance are defined and contrasted, factors affecting the analysis and interpretation of field data presented, and appropriate experimental designs discussed. These general principles are then applied to two detailed case studies, infectious pancreatic necrosis in Atlantic salmon and bovine tuberculosis in dairy cattle, and the lessons learnt are considered in detail. It is concluded that the rate limiting step in disease genetic studies will generally be provision of adequate phenotypic data, and its interpretation, rather than the genomic resources. Lastly, the importance of cross-disciplinary dialogue between the animal health and animal genetics communities is stressed.

Diarrheic calves are fed with milk or milk replacer and oral rehydration solutions (ORS) to ensure energy and electrolyte supply. An easy and time-saving method is the preparation of ORS in milk. As milk-based ORS are hypertonic solutions administration of them may trigger thirst. Therefore, we hypothesized that restrictively fed calves receiving ORS prepared in milk had a higher water intake than restrictively and fed calves receiving ORS prepared in water during diarrheic episodes. The daily water intake was measured in 100 individually-housed Holstein Friesian calves from day 2 to 21 of life. One group of the calves was fed with restrictive amounts of milk, the other group got milk by an automated milk feeder. Nearly all calves spontaneously developed diarrhea within the observation period from day 2 to 21 of life. In cases of diarrhea the restrictively-fed calves received ORS prepared in milk or ORS prepared in water two hours after their milk meal, whereas the -fed calves only got ORS prepared in water. All calves had access to water. The daily intake of water, milk, and ORS and weight gain during diarrheic episode were determined. Data were expressed as arithmetic means (±standard deviation) and analyzed by using a one-way ANOVA or repeated-measures ANOVA. From day 2 to 21 of life calves fed with restrictive amounts of milk had higher water intakes related to the total dry matter intake (DMI) with 1.6 L/kg of total DMI than -fed calves (0.9 L/kg of total DMI) per day. In cases of diarrhea water intake increased in all feeding groups. The calves receiving milk-based ORS had the highest water intake with 1.7 L/d during the period of diarrhea compared to the calves received ORS prepared in water. Moreover, the calves fed ORS in milk showed with 4.6 L/d the highest daily ORS intake. There were no differences in the duration of diarrhea or the daily weight gain during period of diarrhea between the feeding regimens. Therefore, it can be concluded that all feeding regimens were suitable in the treatment of calf diarrhea. The simplest method to treat calves suffering from diarrhea is the preparation of ORS in milk, but then availability of water is absolutely necessary. Moreover, calves drink considerable amounts of water within the first 3 weeks of life and therefore should be provided with water for animal welfare reasons.

Diarrhea is an important cause of morbidity and mortality in neonatal calves. Several enteropathogens are associated with diarrhea in young calves, with Enterotoxigenic (ETEC) infection being the most common type of colibacillosis. The rise of antibiotic resistance in a number of medically important bacterial pathogens has revived interest in the use of bacteriophages as anti-bacterial therapeutic agents. Here we describe the results of a randomized, placebo-controlled, double-blinded study designed to evaluate the effect of an oral bacteriophage cocktail on fecal colony-forming units (CFU). Ten calves were enrolled in the study to either the bacteriophage group or the placebo group for 22 feedings. Calves in the bacteriophage treatment group (n = 6) received a total of 10 plaque-forming units (PFU) (volume = 5 ml) of each of four bacteriophages while the placebo group (n = 4) received only phosphate-buffered saline (5 ml). Fresh fecal samples and blood samples were collected daily from each calf and analyzed for bacterial count and presence of bacteriophage. -infecting phages were recovered from all phage-treated calves at concentrations of 10² to 10³ PFU per gram of rectal contents, but none was detected in serum. Phage treatment caused a reduction in fecal when compared to the control group: the mean log CFU for the placebo-treated group was 9.25 (SE = 0.42) versus 9.11 (SE = 0.34) for the phage-treated group, but the difference was not statistically significant.

The newborn calf's gastrointestinal tract is sterile at birth, but by 3 days of age coliforms, , and are the predominant flora in the feces. During the preweaning period, calves are susceptible to diarrhea that can lead to high levels of morbidity and mortality. Diarrhea has been related with a decrease of beneficial microbiota and an increase of coliform counts in feces. Prebiotic supplements are believed to decrease diarrhea and positively affect some parameters of the immune system. In calves, these supplements have shown some promising effects on intestinal microbial populations but there is limited information about effects on immunity. The main objectives of this study were to evaluate effects of a prebiotic supplement containing fermentation products of lactic acid bacteria on the mucosal immune system by measuring fecal and salivary IgA and to evaluate calf health and growth performance. In this trial 40 Holstein calves were randomly assigned to receive milk replacer with a prebiotic supplement (20 g/day Prebio Support™; Meiji Feed Co., Ltd. Tokyo, Japan) or the same milk replacer with no prebiotic (control). Fecal and salivary IgA, calf health, plasma IgG, and lymphocyte counts were not affected by treatment. count in feces was higher ( = 0.05) and tended to be higher ( = 0.07) in calves fed prebiotic. Prebiotic supplement increased beneficial bacteria in calves, but did not decrease overall incidence of diarrhea in this trial. Calves in this study were all affected by cryptosporidiosis and some were treated with antibiotics, so it is possible that this limited some of the effects of the prebiotic product. Fecal IgA seemed to be a good measure of mucosal immunity, and more studies are needed to develop methods to measure this type of immunity in calves.

Two methods (Scheme A and Scheme B) were developed to optimize the relative weights on quantitative trait loci (QTL) and contributions of selected individuals simultaneously to maximize selection response while constraining the rate of inbreeding to the rate observed in gene assisted selection (GAS). In Scheme A, both the relative weights give to QTL and contributions of the selected individuals were optimized using a genetic algorithm. The possible solutions for relative weights of QTL and contributions of the selected individuals were encoded simultaneously. A physical selection population was used to evaluate the fitness of each encoded solution using stochastic simulation with 50 replicates. The fitness of each solution was the mean of all replicates for accumulative discounted sum of genetic means of all generations in physical selection population. In Scheme B, the optimization for relative weights on QTL was similar to Scheme A, and also was implemented based on a genetic algorithm. However, unlike Scheme A, an optimal contribution algorithm (OC) was used to optimize contributions of selection candidates. When compared with GAS, Schemes A and B resulted in up to 15.88 and 22.26% extra discounted sum of genetic value of all generations in a long planning horizon, respectively. Compared GAS+OC and Scheme B, most of the increase (about 78%) in genetic gain was produced by only optimizing contributions of selected individuals. The optimization for relative weight given to QTL just avoided the long-term loss (about 22%) observed in GAS scheme.

In today's world, emerging and re-emerging diseases have a significant impact on global economies and public health, and with bioterrorism a constant threat this has become a very topical subject in recent years. Bernard Vallat, director general of the OIE, made the statement, "As a result of globalisation and climate change we are currently facing an unprecedented worldwide impact of emerging and re-emerging animal diseases and zoonoses". He is not alone in this thinking, but are we facing an unprecedented impact of diseases and are globalisation and climate change the main driving forces? This paper examines some historical disease outbreaks and the factors that played a role in their emergence and compares these with recent emerging diseases. In doing so it highlights certain challenges that face livestock producers and decision makers today as they grapple with emerging diseases. One of the driving forces for the emergence of diseases is translocation of people and their livestock and this has often been coupled with invading armies or peoples, political unrest and a concurrent environment of socio-economic upheaval. Contact between wild animals, domestic animals and people is another driving force involving the interaction between naïve population groups that induces the emergence of new diseases. Pandemics are not new to human society and nor are many of the driving forces that caused them to occur in the past; what has changed is our increased knowledge and awareness of disease dynamics, allowing identification of challenges for the future and ways of addressing these. Modern farming practices often serve to amplify emerging infectious diseases and modern trade and transport mechanisms and routes have served to sometimes accelerate the spread of disease. How can we reduce the risks and should we only be worried about emerging infectious diseases or are emerging non-communicable diseases just as important in our modern society? This paper serves to explain some of the reasons for the emergence of diseases and to try and answer some of the pressing questions that confront livestock producers today.

The performance of rotationally grazed beef suckler cows and their progeny to slaughter on two lowland grassland management systems differing in stocking rate (SR) and fertiliser nitrogen (N) level was compared over eight years. The two Systems were 1) Intensive (INT): SR of 0.56 (bull production) or 0.71 (steer production) ha cow unit, 211 kg fertiliser N ha, two silage harvests, and 2) Extensive (EXT): SR of 0.69 (bull production) or 0.88 (steer production) ha cow unit, 97 kg fertiliser N ha and one staggered silage harvest. A cow unit was defined as a cow plus progeny to slaughter. On the silage harvesting area, the mean application rate for fertiliser N was 110 and 80 kg ha for first and second harvests, respectively. Herbage dry matter digestibility both pre- and post-grazing was similar ( > 0.05) for the two systems, whereas herbage crude protein concentrations were generally significantly lower for the EXT than the INT system. There was no difference ( > 0.05) between the Systems in cow live weight, body condition score or their changes or in calf live weight gain from birth to weaning. Post-weaning, live weight gain, slaughter weight, carcass weight, kill-out proportion, estimated carcass gain, carcass conformation score or carcass fat score did not differ ( > 0.05) between the systems for heifer, steer or bull progeny. It can be concluded that similar animal performance levels can be expected in an extensive grassland-based suckler calf-to-beef system compatible with the EU, Rural Environmental Protection Scheme as that attained in a more intensive System comprising of both a moderately high SR (~ 1.25 higher) and fertiliser N application (~ 2.1 higher).

In recent years the fate of human and animal pathogen microorganisms as a potential pollutant of the environment has been paid increased attention. Substantial quantities of these compounds and their metabolites are excreted, flushed down the drain, discarded as waste, or left over in animal feedlots. After passing to the sewer, several of these compounds are not adequately eliminated by the methods that are currently used in sewage treatment. Substantial quantities of biosolids and livestock manure end up on agricultural land. Effective sanitation of the environment, particularly of some of its special parts, which can be a source of spreading of diseases, plays an important role in prevention of infectious diseases. In this respect special attention should be paid to the disinfection of infected farm animal excrements. Sanitation of excrements should, on the one hand, ensure effective inhibition of infectious agents and, on the other hand, comply with the requirement of preserving the composition of the manure so it can be used in agricultural production.