A cross-sectional study of suckling calves' passive immunity and associations with management routines to ensure colostrum intake on organic dairy farms.

BACKGROUND: For suckling dairy calves, different management routines to ensure sufficient colostrum intake are applied: visual assessment, hand feeding supplemental colostrum or assistance. However, knowledge on the efficacy of these methods to prevent failure of passive transfer [FPT: serum immunoglobulin (IgG) < 10 g/L] is lacking. Our objectives were to explore FPT prevalence in suckling dairy calves and associations with common management routines to ensure colostrum intake. From 20 organic herds, 156 calf blood samples (mean ± SD; 7.8 ± 1.24 per herd) and 141 colostrum samples from the dams were analysed. All calves suckled the dam. Factors known to affect serum and colostrum IgG were evaluated, including the method applied by the producer to ensure calf colostrum intake and whether it deviated from routine practice for any reason. RESULTS: The prevalence of FPT was 31%. Mean serum and colostrum IgG (± SD) were 16.0 ± 10.0 g/L and 39.4 ± 26.4 g/L, respectively. Only colostrum IgG was found to have a statistically significant influence on the prevalence of FPT. Variation in serum IgG was also explained mainly by colostrum IgG. Of calves receiving colostrum according to farm routine, calves receiving supplemental colostrum with a bottle had lower serum IgG levels than did calves receiving no additional colostrum. However, no within-herd effect was found. With a high between-herd variation, colostrum IgG ranged from 2 to 135 g/L, and only 23% of the samples had a IgG content > 50 g/L. Colostrum IgG was significantly higher in samples collected during spring, compared to samples collected during winter, and lower in 2nd parity cows. CONCLUSIONS: The results indicate that for calves capable of finding the udder and suckling independently, there is no direct benefit of routinely hand feeding colostrum although herd level factors (e.g. feeding, management etc.) may play an important role. FPT prevalence in this study was high, and comparable to that of calves in conventional herds, separating cow and calf at birth. Still, the findings of a high FPT prevalence and inferior colostrum quality indicates a need for improved awareness among dairy producers practicing cow-calf suckling.

The effect of large milk meals on digestive physiology and behaviour in dairy calves.

It is commonly believed that young calves should not be fed more than about 2l of milk per meal. If calves are fed beyond this volume, it is said that the capacity of the abomasum may be exceeded and that milk could enter the rumen. This can disturb the microbial flora/fauna of the rumen and increase the risk of indigestion, diarrhoea and reduced growth. The aim of this study was to examine the effect of large milk meals on digestive physiology and behaviour in dairy calves. Six calves (19-23days of age at the beginning of the experiment) were fed 2l of warm whole milk by teat bottle three times per day, which was the recommended Norwegian feeding regime at the time. The calves were given free access to hay, concentrates and water. During three morning feeding sessions, each separated by 48h, all calves were offered larger meals. The offered amounts were calculated according to the within patient 3-level Response Surface Pathway (RSP) design. The milk given on the three test days contained a contrast medium (barium sulphate), and the animals were radiographed before, during and immediately after intake to reveal whether milk entered the rumen. Four out of the six calves drank more than 5l in one meal and the highest voluntary intake was 6.8l in one meal (13.2% of BW). Abdominal radiographs showed that the abomasum has a large ability for distension. Milk in the rumen was not observed in any of the calves, regardless of intake. The behaviour of the calves was observed for 2h after each test session. No behaviour indicating abdominal pain or discomfort was observed regardless of intake. The results indicate that when warm whole milk is administered from a teat bottle, farmers can increase the amount of milk they offer their calves beyond the traditionally recommended portion size without risk of milk entering the rumen. Hence, farmers who want to feed their calves more milk can do so by increasing meal sizes, and not necessarily by introducing an additional meal.

Growth rate, health and welfare in a dairy herd with natural suckling until 6-8 weeks of age: a case report.

Over a period of two years, growth rate and health were measured for dairy calves allowed to suckle their mothers up to 6-8 weeks of age. Thirty-one calves were weighted weekly, and the mean daily growth rate was 1.2 +/- 0.03 kg from birth up to 13 weeks of age. Illness in calves and young stock was not observed. In the cows, the mean incidences of ketosis, displaced abomasum, puerperal paresis, mastitis, teat injury and retained placenta were 0, 0, 8, 22, 1 and 1%, respectively, during a 6-year period. The mean daily gain of 56 growing bulls was 1.4 kg when slaughtered at 15 months of age, which is higher than the mean daily gain of 0.95 kg in the population. Probiotics, hormones and vaccines were not used, and antibiotics were only used for treating illness. The present study indicates many advantages and few problems when dairy calves are penned together with the cows and allowed natural feeding up to 6-8 weeks of age. This production system was easy to manage, preferred by the farmer, and may satisfy the public concern regarding the practice of immediate separation of cow and calf in commercial milk production.