Smooth Gut Transition in Newborn Calf
Calf
producers face a major hurdle when introducing milk-fed calves to their
first solid feed diet, due to the calf’s immature state of the
gastrointestinal (GI) system. This can lead to a weaning dip. By
choosing the right pre-starter feed, producers can either reduce or
avoid the risks.
Calf
guts undergo a dramatic development in the first 8 to 10 weeks of life,
naturally initiated by solid feed intake as the animals move from a
milk-only diet. It is during this period that the transition to ruminant
begins. It’s also when a weaning dip is often the inevitable outcome of
an unstable and insufficient energy supply from the rumen. For farmers,
a weaning dip brings direct economic consequences in the form of a
longer fattening period for rearing calves with higher feed expenses.
When it comes to dairy heifers, science has demonstrated a link between a
higher rate of pre-weaned growth and a lower breeding age with higher
milk yield at the first lactation.
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| In the first few days after birth, when calves’ nutritional requirements are first met by colostrum from the dam and then by whole milk or milk replacer. But, with the introduction of solid feed, the challenges arise. |
The problem with immature guts
The
immaturity of the GI system is the reason why a calf’s transition to
ruminant can be troublesome. From birth, calves have an esophageal
groove, a muscular structure that shunts milk directly into the
abomasum, by-passing the rumen. What this means is that new-born calves
are functional monogastrics in terms of their ability to break down feed
and absorb nutrients. Because the secretion of digestive enzymes is
highly limited, new-born calves need an easily digestible feed. This is
not a problem in the first few days after birth, when calves’
nutritional requirements are first met by colostrum from the dam and
then by whole milk or milk replacer. But, with the introduction of solid
feed, the challenges arise.
Twin-purpose pre-starter
Pre-starter feed should be introduced during the first week of life. The purpose of this is 2-fold:
- to initiate the development of the rumen,
- to motivate calves to increase their solid feed intake in preparation for weaning.
During
this period, when milk is reduced and solid feed takes over the supply
of energy and nutrients, it’s important that calves absorb the right
amount of energy and nutrients to maintain their average daily weight
gain without a weaning dip. Although calves start to ruminate at the age
of 5 to 8 days, they are not considered ruminants until the age of 6 to
8 weeks. During this time, the rumen microbiota is not yet able to make
sufficient nutrients available for absorption – the reason why calves
depend on monogastric-style nutrient absorption for their daily growth.
So, what can be done to overcome this digestive issue during this
transition period? The answer lies in the choice of pre-starter feed –
and, particularly, a protein source – with a low content of
anti-nutritional factors (ANFs) and allergens. But, first, let’s take a
closer look at the problems that a standard vegetable protein can cause.
Protein components with a negative impact
Soy
is the most commonly used protein source in calf pre-starters. However,
when soy protein is in its untreated form, the content of ANF and
allergens is high. While not a problem for calves with a developed
rumen, in younger animals ANF and allergens have a strong negative
impact on protein absorption and the developing rumen. By extension,
this means these substances compromise the calves’ potential for healthy
growth and development. Soy antigens glycinin and -conglycinin comprise
the greatest part of the protein in the raw soybean. As they are not
destroyed during conventional toasting, these antigens are still present
in conventional soybean meal. Several trials have shown that calves do
not tolerate high concentrations of ß-conglycinin and develop antibodies
against them. This results in damage to the villi in the small
intestine and a shorter feed transition time. Protein digestibility and
nutrient uptake are reduced – and so is calf weight gain. The trypsin
inhibitors in soy pose another challenge to protein digestibility by
forming complex bindings to the protein-splitting digestible enzymes,
trypsin and chymotrypsin. This is a further limiting factor in the
new-born calf gut, where enzyme secretion is already low. A domino
effect of poor protein digestibility is that the relatively high level
of non-digested protein will serve as substrate for pathogenic bacteria –
increasing the risk of diarrhoea.
A speciality solution for a smooth gut transition
A
processing technique developed by Hamlet Protein has made it possible
to reduce the ANF and allergens in soy protein to a minimum. Through the
use of enzymes, the technique also improves the bioavailability of
essential minerals, such as phosphor, zinc and copper. This is the
technology behind HP RumenStart, the company’s latest speciality soy
protein for calf pre-starter feed. The major benefit of HP RumenStart is
that it supports the calf’s transition to ruminant. In doing so, it
helps overcome the shortcomings of immature GI systems during the
critical weaning period. Calves have better access to the energy and
nutrients they need for continued daily growth; and producers are less
likely to suffer the economic consequences of the weaning dip. Or, to
put it another way: healthy animals make a healthy profit. One important
lesson of calf feeding trials over the years is that success is not
only about what you put into pre-starter feed. It’s also about what you
leave out – in this case, the ANF that stand in the way of nutrient
uptake.
Tags:
Dairy Farming