Somatic cell count, endotoxins and mycotoxins are seemingly forgotten threats in sow colostrum and milk that may negatively affect piglets.
Generally considered the ideal feed for neonatal mammals, mother's milk is the exclusive nutrient source during the first days of a piglet's life and the main nutrient source during the suckling period. The benefits of milk and colostrum cannot be overstated. It is rich in energy (lipids, lactose), highly-digestible protein, provides maternal immunity, and affords systemic and mucosal protection.
Despite the benefits, sow milk may conceal several threats to piglets. The emergence of neonatal porcine diarrhea syndrome (NNPDS) in many countries suggests that these threats might deserve closer attention. Comparisons with the dairy cow industry can be illustrative.
1. Somatic cell count
Somatic cell count (SCC) is a key quality parameter of cow’s milk. It has an effect on the market price of milk. The somatic cell count fluctuates in line with the presence of inflammatory processes. In both pigs and cows, the somatic cell count can indicate the general health status, intestinal and udder health, and the milk formation process.
Unfortunately the number of investigations related to SCC in sow milk is limited, and the reported levels differ greatly. Levels of 2 to 3x106 cells/ml in colostrum and 5x105 cells/ml in mature milk or higher seem to be quite normal. In the first week after farrowing, the SCC typically falls by 10 percent and remains stable. Recently, the influence of SCC on piglet body weight has been investigated. In light of these significant correlations, the SCC should be monitored more closely for its negative effects in neonatal piglets.
Table 1. Sow’s milk SCC is correlated to lower piglet body weight (BW)
Endotoxins are thermostable lipopolysaccharides (LPS) found mainly in the cell walls of Gram-negative bacteria, i.e., E.coli, Salmonella, etc., and are released when the bacterium dies in the host’s body. Pigs are continuously exposed to endotoxins present in the ground, air, water and the gastrointestinal tract. Once LPS enter the bloodstream, they can cause fever, chills, shock, leukopenia and a variety of other symptoms, depending on the condition of the infected organism. Endotoxins can be involved in the occurrence of mastitis, metritis and agalactia (MMA), and acute respiratory distress (PPD) syndromes. Lipopolysaccharides can also increase a pig’s sensitivity to deoxynivalenol (DON), a major mycotoxin that can cause vomiting, diarrhea and weakened immune function.
LPS content has been used as a quality parameter in heat-treated milk for human consumption, set at a maximum 400 EU/ml. To date, there is little research on endotoxin presence in colostrum and mature sow milk as well as on effects of endotoxin challenged colostrum or milk on piglet growth. In this context, the findings of Shreeve et al. (1970) that piglets from sows immunized with E. coli extract developed hypersensitivity against different endotoxin challenges are interesting as well.
Aflatoxins are naturally-occurring mycotoxins produced by the fungi species Aspergillus flavus and Aspergillus parasiticus, of major concern to the dairy industry. Aflatoxin B1 is the most carcinogenic natural compound known to date. Aflatoxin M1, the natural metabolite of Aflatoxin B1, has a carry-over rate of 1 to 6 percent in milk. Concentrations of Aflatoxin M1 above 0.05 μg/kg in the EU or 0.5 μg/kg in the U.S. are considered undesirable and must be discarded — representing lost revenue and extra disposal costs for dairy producers.
It is young pigs and pregnant sows that are often more affected than other stages. Aflatoxin effects can include general symptoms of slow growth, reduced feed intake and immune suppression. Liver toxicity, kidney inflammation and systemic hemorrhages are also characteristic of aflatoxin effects. The damage aflatoxins can cause in suckling piglets is still not investigated.
Given the complex nature of the harm to piglets that includes some well-documented risks and other, less-researched potential threats, caution is advised. It may be helpful to take a cue from the dairy cow industry in identifying appropriate preventive measures.
There are some steps that swine producers can take to mitigate the SCC-endotoxin-mycotoxin triple threat. Biosecurity and robust mycotoxin risk management, including strategies to control endotoxins, are important.
Modern mycotoxin binding and deactivating agents can help to control the endotoxin risk as well.
Our own trials have shown that using certain complex phytogenic feed additives in all sow feed can improve zootechnical performance parameters of sows, as well as quantity and quality of sow milk produced, reducing SCC particularly in the birth close period.