Each year, more than 200 million people suffer from malaria around the world, and every two minutes a child dies from the disease. The disease is most common in poor areas and is itself a contributing factor to poverty: a sick person cannot perform his or her daily tasks, which can lead to a loss of income for the household. At the societal level, the healthcare system and the economy of countries, where malaria is endemic, are affected. At the Swedish University of Agricultural Sciences (SLU), the fight against malaria continues through novel research on how to control and trap the mosquitoes that carry the malaria parasite. As there is currently no effective vaccine available to prevent malaria, controlling the mosquitoes that spread the parasite is imperative for preventing the spread of the disease. However, the existing techniques for indoor malaria mosquito control have been put to the test, due to the development of pesticide resistance in mosquito populations and behavioral changes in the mosquitoes. As a result, there are now more people being bitten outdoors. Therefore, there is an urgent need for innovative control methods that complement the current strategies and specifically focus on mosquitoes that are active outdoors. Outdoor-based traps can be substantially more efficient when baited with synthetic human and animal odours. For example, it has been demonstrated that cattle urine attracts many blood sucking insects, in various physiological stages and different species of mosquitoes. Adult female malaria mosquitos use the urine as a supplementary nitrogen–rich meal, enhancing flight mobility, survival and reproductive traits. Researchers from SLU took this into account when they initially developed a synthetic cattle urine odour to lure malaria mosquitoes into traps. During one year, the researchers collected seasonal information on the malaria mosquito species populations along with data on the presence and prevalence of malaria in mosquitoes and humans. At the onset of the second year, they installed 50 traps baited with the synthetic cattle urine odour, powered by solar panels, in one of the villages and continued collecting entomological and parasitological data. By mass trapping, they were able to reduce the population of malaria mosquitoes by up to 70% and malaria prevalence by up to 60%, despite a major malaria epidemic affecting the region, said Professor Rickard Ignell, Department of Plant Protection Biology, SLU.

Johne’s Disease or paratuberculosis is a chronic disease of ruminants which is responsible for large economic losses in the dairy sector. The disease is caused by Mycobacterium avium subspecies paratuberculosis (MAP), which typically infects calves that remain latently infected during a long period, making early detection of infection especially challenging. Cow-to-calf transmission can occur in-utero via milk/colostrum or faecal-orally, so understanding the different transmission routes to calves is important in informing control recommendations. The aim of a longitudinal study carried out by researchers at the Royal Veterinary College was to measure the association between the transmission routes via the dam and the environment on a calf that subsequently tested serologically positive for MAP. The study comprised of 439 UK dairy calves from 6 herds enrolled between 2012 and 2013. These calves were followed from birth until 2023. Individual calf data was captured at birth. During follow-up, individuals entering the milking herd were quarterly tested for the presence of MAP antibodies using milk ELISA. Cox regression models were used to measure the association between exposure from the dam (in-utero and/or colostrum) or from the environment (long time in dirty yard) and time to first detection of MAP infection. In conclusion, the researchers found that: 1) Map infection risk is partly driven by the dam’s infection status. 2) Calves from infected dams have higher MAP infection risk, regardless of the dam’s test status at calving. 3) Spending prolonged time in a dirty yard increases the risk of MAP infection. 4) The dam’s impact on MAP risk extends beyond colostrum transmission. 5) MAP persistence in commercial dairy herds results from a combination of dam-related and environment-related factors.

When dairy cows are fed diets with reduced protein concentrations – aimed at decreased environmental nitrogen pollution from their manure such as nitrate leaching, nutrient-laden run-off and ammonia volatilization – their milk production can suffer. Supplementing the amino acid histidine may help in maintaining, and even increasing, milk and milk-protein yields. That’s the conclusion of a new study conducted by an international research team led by Alexander Hristov, a senior researcher at Penn State University. The researchers recently published their findings in the Journal of Dairy Science. Histidine is an essential amino acid for protein synthesis, Hristov explained. He added that earlier studies in Europe have shown that low histidine levels can limit milk production in dairy cows fed diets based on grass silage, which is the predominant forage in Northern Europe. Limited histidine was not considered a challenge for dairy cows fed typical North American diets until research conducted in Hristov’s lab in the College of Agricultural Sciences at Penn State a few years ago revealed the problem. In those experiments, blood histidine concentrations dropped significantly when cows were fed reduced-protein diets aimed at curbing nitrogen losses and ammonia emissions from manure.

The recently published series of experiments also confirmed the importance of histidine to maintain milk production and milk protein content when cows were fed diets with reduced protein concentration. “The culmination of this research was the recently published meta-analysis of 17 studies which concluded that histidine supplementation of dairy cow diets increased feed dry matter intake, milk yield and milk protein concentration,” Hristov said. “Notably, and as Penn State research has shown, the increase in milk protein concentration with histidine supplementation was up to four times greater for cows fed diets that had lowered protein content than diets formulated to provide adequate protein intake, according to diet-formulation models.” Histidine is unique among the essential amino acids because there are body reserves that can serve as sources of histidine and mask short-term deficiencies, Hristov said.

For that reason, histidine effects in dairy cows should be studied in long-term, continuous-design experiments. “Further, microbial protein synthesized in the rumen – which is the main source of amino acids for the cow – is low in histidine, relative to other potentially milk-limiting amino acids,” Hristov said. “That supports our hypothesis that histidine becomes the first limiting amino acid when cows are fed low-protein diets. So, the role of microbial protein as a source of amino acids for milk protein synthesis and body functions becomes even more critical.”

Coccidiosis is an intestinal disease caused by unicellular parasites that usually occurs in young dairy or beef calves between 3 weeks and 6 months of age. Although it is rarely fatal, it can cause extensive gut damage and ill-thrift and is commonly seen under intensive management conditions with high stocking rates.

Autumn-born calves are at greater risk, with Cocci requiring warmth and moisture. A wet September and October increases infection risk as the environment becomes more favourable for the occysts to spread from calf to calf.

Veterinary specialists Murray Direct said calves become infected by consuming coccidiosis eggs from pasture, feed, waste and bedding, or by licking contaminated calves. The parasite can exist for months in their surroundings and failure to control the disease can influence future productivity levels, including growth rates, as well as delaying the onset of puberty, leading to milk loss production in dairy calves.

Third-generation dairy farmer, Darren Coombes, who farms with his son Tim on 890 acres near Bridgwater, Somerset in the UK, believes feeding a coccidiostat to his dairy calves can help control the disease. He recently had an outbreak affecting a fifth of his calves. 

Coombes milks 425 cows – year-round calving Holsteins – supplying Muller and Sainsbury’s. Animals are milked twice daily, producing 10,500 litres at 4.3% fat and 3.25% protein.

“We didn’t lose any calves, but we lost a lot of growth and it took the calves a long time to recover,” he said.

His vet recommended the calves be fed the coccidiostat Deccox and, alongside improved cleanliness, it has helped get on top of the outbreaks.

Coombes said newborn calves receive colostrum for the first 3 days. Calves are kept in pens for the first week and at day 4 they transition onto a milk replacer with 3 litres fed in a bottle twice a day. From birth, calves are given clean water and free access to fresh straw and Mole Valley Farmers’ NSP NPP Calf Rearer 18+ Deccox, which is an 18% protein rearer nut with an added coccidiostat to help treat and manage coccidiosis.

“It is a very consistent, palatable product and calves love it. After 7 days, calves move onto one of the 2 Forster-Technik automatic milk feeders where they are kept in groups of 30. Calves get fed 4 feeds a day and can have a maximum of 8 litres in 24 hours. At day 49, the milk is gradually reduced and calves are weaned at day 56.”

Calves stay in the same group until they are 6 months old. After 5 months they are introduced to 1kg of homegrown rolled barley and ad-lib grass silage with the rearer nut cut back to 1kg. Deccox is removed at 9-10 months. Coombes notes: “It has completed kept coccidiosis at bay. We tried different things and we could never really get to the bottom of it until we introduced the Deccox.”

But hygiene is key, too. Calf sheds are disinfected and steam-cleaned between batches and straw bedding is also replenished liberally to keep calves dry.

Andy Adler of Molecare Farm Vets said preventing faecal contamination of water and feed troughs is crucial in controlling coccidiosis. “Raising feed and water troughs alongside regular cleaning is very important to prevent faecal-to-oral transmission. Straw bedding should be replenished often so calves are only eating fresh, clean straw.”

Scientists have collaborated to produce the first gene-edited calf with resistance to bovine viral diarrhoea virus (BVDV). The study, published recently in PNAS Nexus, is the result of a collaboration between several universities and industry players. BVDV is one of the most important viruses affecting the health and well-being of cattle worldwide and has been studied by researchers since the 1940s when it was first identified. The virus does not affect humans, but is highly contagious among cattle and can cause severe respiratory and intestinal disease. BVDV can be devastating to pregnant cows, as it can infect developing calves, causing spontaneous abortions and low birth rates. Some infected calves survive to birth and remain infected for life, shedding massive amounts of virus to other cattle. Over the past 20 years, the scientific community has discovered the key cellular receptor (CD46) and the site where the virus binds to this receptor and causes infection in cows. In this latest study, scientists have modified the virus binding site to block infection. Aspen Workman, lead author and researcher at ARS’ US Meat Animal Research Center (USMARC) in Clay Center, Nebraska, said, “Our goal was to use gene-editing technology to slightly modify CD46 so that it doesn’t bind the virus but still retains all its normal functions in cattle. The scientists first tested this idea in cell culture. After seeing promising results in the lab, Acceligen edited cattle skin cells to develop embryos carrying the modified gene. These embryos were transplanted into surrogate cows to test whether this approach could also reduce viral infection in live animals. It worked, and the first CD46 gene-edited calf, named Ginger, was born healthy on 19 July 2021. The calf was followed for several months and then challenged with the virus to see if it could become infected. She was housed for a week with a BVDV-infected dairy calf that was born shedding virus. Ginger’s cells showed significantly reduced susceptibility to BVDV, resulting in no observed adverse health effects. Scientists will continue to monitor Ginger’s health and ability to produce and rear her own calves. This promising trait is still in the research phase and no associated cattle are currently entering the US food supply.

A Holstein cow at the ripe old age of 14 has set a new lifetime production record in the USA. Owned and bred by the Dankert family at Nor-Bert Farm in Bremen, Indiana, the cow named Nor-Bert Colby Connie has pumped a record 486,300 pounds (over 22 tonnes) of milk. And she is still producing, as Connie has just calved again and is increasing her production every day. Connie has equally impressive results for her milk quality components with a lifetime record of 12,275kg of fat and 8,045kg of protein in her last completed lactation. These massive fat and protein totals are currently the highest lifetime fat and protein totals in the Holstein Association USA database. This new production record comes in quick succession to that set by another US cow, Chrome-View Charles 3044, who set the record earlier this year with a total of 217 tonnes of lifetime milk. These lifetime production records have highlighted the scope of what Holstein cows can achieve.

Hundreds of cattle in Iowa died from extreme heat and humidity in late July, Reuters reported, citing the state and livestock producers, as the world recorded its hottest month on record. The deaths show the toll of severe weather on livestock and food production. The losses further reduce the US cattle herd, already the smallest in decades, after drought forced ranchers to slaughter more cows for lack of pasture to feed them. While not massive in numbers, producers said the recent deaths were unusual. Cattle also died of heat in Kansas and Nebraska, state officials said. Gary Vetter, who raises cattle in western Iowa, said he worked to protect local herds, but about 53 cattle died at three of his neighbours’ feedlots during the last week of July. “They just started falling off, and there was nothing you could really do about it,” Vetter said. “I’ve never seen anything like it.” Heat is usually most dangerous for the heaviest cattle, which weigh more than 1,000 pounds (450 kg), but temperatures and humidity rose so high that even lighter 700-pound cattle died, said Vetter, whose farm near Iowa had a thermometer reading of 47 degrees Celsius (113 degrees Fahrenheit). The US Department of Agriculture (USDA) is offering disaster assistance that could help compensate producers whose cattle died.

Monitoring dairy calves with precision Internet of Things (IoT)-based technologies leads to earlier diagnosis of calf-killing bovine respiratory disease (BRD), according to research from three US universities. Researchers from Penn State University, the University of Kentucky and the University of Vermont say the findings offer dairy producers an opportunity to improve farm economics. Melissa Cantor, assistant professor in Penn State’s College of Agricultural Sciences, said IoT, with its embedded devices equipped with sensors, processing and communication capabilities, software and other technologies to connect and share data with other devices over the internet, allows farmers to closely monitor and analyse calf conditions. IoT generates a huge amount of data, so to make it easier to understand and prove calf health problems, the researchers used machine learning – a branch of artificial intelligence that learns the hidden patterns in the data to distinguish between sick and healthy calves. “We put leg bands on the calves, which record data on the activity behaviour of dairy cattle, such as the number of steps and time spent lying down. And we used automatic feeders that dispense milk and grain and record feeding behaviour, such as the number of visits and litres of milk consumed. Information from these sources signalled when a calf’s condition was about to deteriorate”. In the study of 159 dairy calves, the system achieved exceptional accuracy in identifying sick and healthy calves, predicting 70% of sick calves 4 days before the actual diagnosis and 80% of calves that developed chronic disease within the first 5 days of illness.

Researchers from the University of Glasgow’s James Watt School of Engineering are part of a new consortium which is developing the first commercial one-step rapid test for calf pneumonia. Global Access Diagnostics (GADx), a social enterprise prioritising equitable access to diagnostics and driving local manufacturing, today announced the development of RaDiCal, a one-step molecular lateral flow test to enable rapid diagnosis of pneumonia, one of the most significant diseases affecting calves. The test is being developed through a collaborative consortium, including representatives from the University of Surrey, University of Glasgow, Cardiff University, and Westpoint Farm Vets, to provide a low-cost platform to be used by veterinarians or farmers on-farm.

The test is a pioneering molecular lateral flow platform which can be linked to a mobile phone digital platform for easy interpretation of results, enabling farmers and vets to diagnose calves on-farm, and subsequently take rapid and informed action to facilitate improved disease management and support responsible antibiotic stewardship. Professor Jon Cooper is leading the University of Glasgow’s contribution to RaDiCal. For several years now, Professor Cooper and colleagues have been working to develop low-cost lateral-flow diagnostics for diseases including malaria and schistosomiasis for use in areas with limited access to healthcare. They have been field-tested in Uganda with support from local researchers and government.

Two European Union countries – Germany and France – have more than a third of all the dairy cows across member states. Between them, they had more than 7 million cows in 2022 out of a total of 20.1 million, according to Eurostat figures. Germany had the largest dairy cow population within the EU, recording 3.8 million animals, accounting for 17% of the total EU dairy population. France had 3.2 million animals while Poland had the third-largest national herd with just over 2 million animals.

The majority of EU countries recorded an annual decline in cow numbers in 2022, with France recording the largest loss with 91,720 (2.7%) fewer animals than in the previous year. One country to buck the trend was Austria, which recorded the largest expansion within the EU last year. The population reached 551,000 head, up 24,090 (4.6%) on 2021. At the other end of the scale, Malta continued to be the smallest milk-producing nation within the EU, with just 6,120 recorded in 2022. There are likely to be further falls in cow numbers this year. In its short-term dairy outlook, the European Commission forecasted a drop of 0.2% in milk production for 2023. With a forecasted 1% increase in slaughtering, there will be less milk available in 2023 due to a declining dairy herd.