Introduction
Calf nutrition and management seems to be divided into two distinct periods – namely, the first day of life and everything after. We all know of the importance of Day 1 – the all important period when newborn calves can absorb immunoglobulins into the bloodstream without digestion. This is the time frame when colostrum feeding (or use of colostrum supplements/replacers) is essential to provide the calf with passive immunity and critical nutrients for survival.
But, after the first 24 hours of life, most dairies and calf ranches move the newborns – now 24 to 36 hours of age, into the “normal” housing and management of the calf raising operation. Of course, these “babies” may get special treatment – teaching them to drink from the nipple or bucket, vaccinations, etc. But, for the most part, we assume that this young animal can be fed and managed like all other calves.
So, here’s the question – is the day-old calf able to digest, absorb and utilize nutrients like its brothers and sisters several weeks older? Is its immune system equally competent to fight pathogens as calves much older? The short answer is no and no. The objective of this Calf Note is to explain some of the differences and propose that we might consider a different approach to managing “Day 2” calves. We’ll consider differences in three areas – gut flora (bacteria), digestion and metabolism and immunity.
Bacterial flora. When the calf is first born, the digestive tract is sterile. During the first 24 hours or so of life, bacteria take up residence in the tract, colonizing from “both ends” (mouth and anus) and eventually, large numbers of bacteria can be found throughout the tract.
By 24 hours of life, there is a considerable population in the tract, but many of these bacteria are “transient” – i.e., they become established in the gut because they were inoculated via feed or the environment. They are not normally found (at least in measurable concentrations) in the gut of older calves. Much work was done in the 1940’s and 1950’s to understand the changes in bacterial populations in the rumens of newborn calves. Similar changes likely occur in the intestine of young calves; however, data are less available.
Digestion and metabolism. The enzymes and gastrointestinal secretions that calves use to digest their feed do not turn on “magically” at 24 hours of age. Many or most of them gradually increase over time. As an example, Huber et al. (1961) measured enzyme activity in milk-fed calves from 1 to 44 days of age. Mean activity of enzymes in the pancreas are in Figure 1. As you can see, activity of all enzymes (lipase, protease and amylase) were lower at day 1 than other days, and then increased by day 8. Thereafter, activities don’t change dramatically. Similar data have been reported by other researchers (Ternouth and Buttle, 1973; Ternouth et al., 1976; Sissons, 1981). Generally, activities of many (but not all) enzymes tend to increase with time. However, this is often dependent on the type of diet fed, amount of solid feed consumed (and subsequent rumen development) and age. But, the data appear clear that most enzymes are less active in the first few days of life. Thus, we shouldn’t assume that calves are ready to digest the same type of diet on day two that they will be on day 20.
Immunity. Absorption of immunoglobulins is complete by 24 hours of age. The process of intestinal maturation (called intestinal closure) that terminates by the end of the first day. Many other components of the immune system are still depressed by day 2 – levels of complement decline in the first couple of days. Other aspects of the calf’s immune response are less well developed and require time to fully mature. Rossi et al. (1981) and many others have documented the immaturity of the neonatal immune system.
A dietary approach
So, if a calf on day 2 is still not “normally developed” (at least compared to a calf at 14-21 days of age), how do we manage calves to accommodate differences in their metabolism? Are current methods of feeding and management appropriate for day 2 calves? The short answer is that we don’t know for sure. However, we can look at how Nature approaches day 2 and try to learn how our nutrition and management could adapt to improve calf performance.
Table 1 contains the nutrient and immunoglobulin (total Ig and IgG) content of colostrum (first milking after calving) and transition milk collected on day 2 and day 3. These are compared to normal milk (adapted from Foley and Otterby, 1978).
As we can see, the composition of transition milk varies significantly from both colostrum AND mature milk in terms of solids, nutrition and immunoglobulin content. The content of IgG is still significant. According to Foley and Otterby, the content of IgG is about half that of first-milking colostrum. If we calculate the intake of nutrients and IgG (assume a calf consumes 4 liters of colostrum, transition milk and mature milk), we see that there are still lots of differences between intake of day 2 transition milk, mature milk and colostrum. These figures are in Table 2. Compared to colostrum, day 2 milk contains less solids (-41%), fat (-42%), protein (-74%), casein (-21%), total Ig (-60%) and IgG (-52%). However, compared to colostrum, calves fed day 2 milk will consume more lactose (+63%) due to changes in lactose content of day 2 transition milk compared to colostrum.
When we compare intake on day 2 compared to intake of 4 L of mature milk, we see calves fed day 2 milk eat more solids (+9%), protein (+65%), casein (+52%), Ig and IgG. Intake of fat is similar and lactose is slightly lower than when calves drink mature milk.
What are the implications to this information? It appears that calves on day 2 will consume more solids, protein and IgG when they drink transition milk compared to whole milk. Blättler et al. (2001) and Bühler et al. (1998) reported that feeding more colostrum had positive effects on maturation of the intestine, enzyme activity and digestion.
Of particular interest is continued feeding of relatively large amounts of IgG. On day 2, calves fed transition milk still receive over 50 grams of IgG. If we assume that dairy cows provide IgG in their colostrum and milk for a reason, we might conclude that continued feeding of IgG confer continued benefit to calves even though they are not absorbed into the bloodstream. And, indeed, many published papers suggest that continued feeding of IgG and other functional proteins from colostrum. So, many extension publications recommend continued feeding of colostrum for three days after birth:
- https://ag.udel.edu/anfs/faculty/kung/articles/importance_of_colostrum_for_calv.htm
- https://www.uky.edu/Ag/AnimalSciences/dairy/extension/nut00109.pdf
- https://www.farmllc.org/custom3.html
- https://www.rennut.com/articles/pdf/Newborn%20Calf%20Care.pdf
Unfortunately, many producers don’t have transition milk available. Some sell their transition milk; others move calves from the dairy to a calf ranch on day 1 and may only have access to commercial milk replacer.
One potential solution is to add a small amount of first milking colostrum or commercial colostrum replacer into milk replacer.
References
Anderson, K. L., T. G. Nagaraja, J. L. Morrill, T. B. Avery, S. J. Galitzer, and J. E. Boyer. 1987. Ruminal microbial development in conventionally or early-weaned calves. J. Anim. Sci. 64:1215-1226.
Blättler, U., H. M. Hammon, C. Morel, C. Philipona, A. Rauprich, V. Romé, I. Le Huërou-Luron, P. Guilloteau and J. W. Blum. 2001. Feeding colostrum, its composition and feeding duration variably modify proliferation and morphology of the intestine and digestive enzyme activities of neonatal calves. J. Nutr. 131:1256–1263.
Bühler, C., H. Hammon, G. L. Rossi, and J.W. Blum. 1998. Small Intestinal morphology in eight-day-old calves fed colostrum for different durations or only milk replacer and treated with long-R3-insulin-like growth factor I and growth hormone. J. Anim. Sci. 1998. 76:758–765.
Bryant, M. P., N. Small, C. Bouma, and I. Robinson. 1958. Studies on the composition of the ruminal flora and fauna of young calves. J. Dairy Sci. 41:1747-1766.
Foley, J. A., and D. E. Otterby. 1978. Availability, storage, treatment, composition, and feeding value of surplus colostrum: A review. J. Dairy Sci. 61:1033-1060.
Huber, J. T., N. L. Jacobson, R. S. Allen, and P. A. Hartman. 1961. Digestive enzyme activities in the young calf. J. Dairy Sci. 44::1494-1501.
Rossi C.R., G. K. Kiesel, R. S. Hudson, T. A. Powe, and L. F. Fisher. 1981. Evidence for suppression or incomplete maturation of cell-mediated immunity in neonatal calves as determined by delayed-type hypersensitivity responses. Am. J. Vet. Res. 42:1369-70.
Sissons, J. W. 1981. Digestive enzymes of cattle. J. Sci. Food Agric. 32:105-114.
Ternouth, J. H., and H. L. Buttle. 1973. Concurrent studies on the flow of digesta in the duodenum and of exocrine pancreatic secretion of calves. Br. J. Nutr. 29:387-397.
Ternouth, J. H., J.H.B. Roy, and S. M. Shotton. 1976. Concurrent studies on the flow of digesta in the duodenum and of exocrine pancreatic secretion of calves. 4. The effect of age. Br. J. Nutr. 36:523-535.