Feeding colostrum and transition milk facilitates digestive tract functionality recovery from feed restriction and fasting of dairy calves

The objective of this study was to evaluate the digestive tract recovery and metabolism of feeding either bovine colostrum (BC), transition milk (TM), or milk replacer (MR) after an episode of feed restriction and fasting (FRF) in dairy calves. Thirty-five Holstein male calves (22 ± 4.8 d old) were involved in a 50-d study. After 3 d of feeding 2 L of rehydration solution twice daily and 19 h of fasting (d 1 of study), calves were randomly assigned to one of the 5 feeding treatments (n = 7): calves were offered either pooled BC during 4 (C4) or 10 (C10) days, pooled TM during 4 (TM4) or 10 (TM10) days, or MR for 10 d (CTRL) at the rate of 720 g/d DM content. Then, all calves were fed the same feeding program, gradually decreasing MR from 3 L twice daily to 2 L once daily at 12.5% DM until weaning (d 42), and concentrate feed, water, and straw were offered ad libitum until d 50. Citrulline, Cr-EDTA, β-hydroxybutyrate (BHB), and nonesterified fatty acids (NEFA) in serum and complete blood count (CBC) were determined on d -3, 1, 2, 5, and 11 relative to FRF, except BHB and NEFA at d -3. Volatile fatty acids (VFA), lactoferrin (LTF), IgA, and microbiota (Firmicutes to Bacteroidetes ratio and Fecalis prausnitzii) were analyzed in feces on d 5 and 11 before the morning feeding. Health scores were recorded daily from d -3 to d 14 as well as d 23 and 30. Feed concentrate, MR, and straw intake were recorded daily, and body weight on d -3, 1, 2, 5, and 11 and weekly afterward. Calf performance, intake, serum Cr-EDTA, CBC, fecal LTF concentrations and microbiota parameters were similar among treatments throughout the study. Serum NEFA concentrations were greater in TM4, TM10 and C10 calves compared with the CTRL ones from d 2 to 11, and after the FRF, serum concentrations of BHB were lower in CTRL calves than in the other treatments, and on d 11, serum BHB concentrations in the long treatments (C10 and TM10) remained greater than those in the shorter ones (C4 and TM4) and CTRL. Serum citrulline concentrations were similar on d -3 and 1 in all treatments, but they were greater in C4, C10, TM4, and TM10 on d 2 and 5, and on d 11 they were only greater in C10 and TM10 than in CTRL calves. Fecal IgA concentrations tended to be greater in C10 than in CTRL, TM4, and TM10 calves, and in C4 and TM10 than in CTRL animals. Fecal propionate proportion was lesser in C10 than in CTRL, TM4, and TM10 calves, while butyrate was greater in C4 and C10 than in TM4 and CTRL calves. The proportion of non-normal fecal scores of C10 fed calves was greater than TM4 and TM10 calves. Results showed that TM and BC may help to recover intestinal functionality, provide gut immune protection, and increase liver fatty acid oxidation in calves after a FRF episode.

Short communication: The biological value of transition milk: analyses of immunoglobulin G, IGF-I and lactoferrin in primiparous and multiparous dairy cows

Colostrum (the first mammary gland secretion after calving) is known to contain high concentrations of nutrients as well as bioactive substances (including immunoglobulins, growth factors, and antimicrobial factors) to ensure neonatal survival. Due to its immunomodulatory, antibacterial, and antiviral activities, bovine colostrum has been used not only in calves but also in the prevention and treatment of human gastrointestinal and respiratory infections. Transition milk is the mammary secretion from the second milking to the sixth, which may contain these bioactive compounds to a lesser extent. The objective of the present study was to measure IGF-I, immunoglobulin G (IgG), and lactoferrin (LTF) concentrations in colostrum and transition milk of primiparous and multiparous cows to further assess its potential use in veterinary and nutraceutical applications. The results demonstrated that the concentrations of these three bioactive molecules decrease from the first milking to the tenth. Concentrations of IGF-I and LTF were greater in multiparous than in primiparous cows. Also, lactation number interacted with milking number in IGF-I, since primiparous cows had a smoother decline of IGF-I concentrations than multiparous ones. Overall, transition milk from the second milking showed a 46% decrease in the analysed colostrum bioactive molecules. Therefore, further studies are needed to apply this knowledge in neonate farm management practices or in developing pharmaceutical supplements from farm surpluses.

Residues from veterinary medicinal products, growth promoters and performance enhancers in food-producing animals: a European Union perspective

The authors present an overview of the presence of residues from veterinary medicinal products, growth-promoting agents and performance enhancers in food-producing animals, as a result of administering these substances--legally or illegally--on farms. The current situation in the European Union (EU) is represented by an analysis of the 2004 results from the national residue monitoring plans of EU Member States. Aspects of ante-mortem and postmortem inspection are also considered, as well as the practical challenges facing veterinary inspectors attempting to uncover illegal uses and prevent public health risks. Substances which are considered illegal because their risks have not yet been assessed, such as those employed in minority species or for minor uses, are also discussed.