An estimated 56% of health problems in early life relate to diarrhea, making it a number one health issue for newborn calves. It accounts for 52.2% of mortality of unweaned calves, and is also a major cause of poor growth, increased labor requirements and increased costs. In the United States, 23.9% of dairy heifers are affected by and treated for scours and preweaning mortality is estimated at 7.8% according to Cornell University and the National Animal Health Monitoring System (NAHMS, 2007), respectively.
Outbreaks of infection causing calf diarrhea are often rapid and multifactorial in nature. Major enteric pathogens known to cause calf diarrhea are viruses (i.e., bovine rotavirus, bovine coronavirus (BCoV), bovine viral diarrhea virus (BVDV) and microscopic parasites (Cryptosporidium parvum), as shown in Figure 1. Bacteria such as Salmonella (S.) enterica, Escherichia (E.) coli, Clostridium (C.) perfringens, are often only secondary infection agents.
Figure 1. Prevalence of infectious agents.
As antibiotics are not effective against viruses and parasites, their application to counter diarrhea makes little sense. Antibiotic use in these cases has several disadvantages. First, calves who have undergone antibiotic therapy produce 492kg (1084lbs) less milk during first lactation, according to Mike van Amburgh of Cornell University and confirmed by others. Second, antibiotics destroy the normal, beneficial intestinal bacteria and thereby disrupting intestinal health. Third, destruction of Gram-negative bacteria releases endotoxins, the lipopolysaccharide components of cell walls.
According to James Cullor of UC Davis, the general effect of endotoxins are well chronicled and are reported to include lethargy, respiratory distress, transitory hyperthermia followed by hypothermia, decreased systemic blood pressure, increased heart rate followed by decreased cardiac output, diarrhea, changes in blood cell counts, and alterations in the blood coagulation system. Fourth, antibiotic use is associated with antibiotic resistance.
A better way
Bovine colostrum offers a kind of survival kit from the mother to the newborn calf to protect against challenges at the beginning of life. It benefits the calf ’s immune, hormonal and digestive systems, and contains everything required for healthy, productive development along with an enormously high nutrient content.
With colostrum intake shortly after birth, in one shot the calf gets all the 97 immune factors (constituents that build the immune system), 87 growth factors (bio-identical hormones and hormone precursors) and a variety of different probiotics along with prebiotics that help grow and feed the beneficial flora in the gut. This passive immunity transfer protects the calf until it establishes its own pathogen recognition and disposal systems.
The best composition of hormones and growth factors such as relaxin, prolactin, insulin, IGF-1, IGF-2, and leptin are only available via colostrum. The beneficial contents of colostrum milking can persist through the fifth milking—or three days after parturition (Figure 2).
Figure 2. Transition state colostrum remains richer than standard milk.
Colostrogenesis begins 3 to 4 weeks prior to parturition with the accumulation of hormones, growth factors (IGF-I and IGF-II) and transforming growth factors (TGF-β1 and TGF-β2) which activate mammary secretory cell.
Because colostrum transfers antibodies to a calf, cow breeders can essentially design colostrum for the coming calves by vaccinating cows 60-30 days before calving against the most frequent pathogens appearing on the farm. In that way, the newborn calf gets selective protection against existing pathogens in the farm environment.
Colostrum from vaccinated cows has demonstrated ability to kill bacterial and viral invaders, stimulate tissue repair (particularly the bowel lining), fight a variety of allergens and neutralize toxin-producing organisms. It has also proven effective in treating severe diarrhea. According to the 2007 National Animal Health Monitoring System survey, approximately 19% of dairy heifer calves in the US had failure of passive transfer.
Beat the clock
Speed is crucial when it comes to harvesting and feeding colostrum to newborn calves, for several reasons. First, the composition of colostrum changes following removal of placenta.
Second, newborns lack the enzymes that breakdown colostrum’s active components— these are developed later.
Third, it is important to seize the opportunity afforded by the ‘open gut’ phenomenon, in which the upper part duodenum remains open for direct absorption of colostrum ingredients into the calf blood stream. (Note that pathogens can also enter the open gut).
Proper feeding of the cows in late lactation and dry period, can positively influence colostrum quality and quantity. Mycotoxins—found in both grains and contaminated straw—can impair immune and liver function, so robust mycotoxin risk management is advisable.
Agents that cause diarrhea are present in a calf’s environment. Improvements in environmental sanitation and the reduction of stressors (e.g. overcrowding, frequent diet change, heat stress, etc.) coupled with proper colostrum management can help support healthy calves.
Every calf that is born on a farm represents an opportunity to maintain or increase herd size, to improve the herd genetically, and to improve economic returns. Pathogen invasion can create additional costs, health issues and poor performance. Good quality colostrum can allow cow breeders to achieve a successful outcome.