The inability of some calves to suckle has been observed by many breeders. Studies (USA) suggest that as much as 30% of post partum sucking problems are due to the lack of an instinctive ability to suck which if unattended leads to death. This condition is often referred to as the “dummy or silly” calf syndrome or poor sucking reflex syndrome (PSR).Other factors that cause poor sucking calves include the month and year of birth, temperature and rainfall, neonatal infections, prolonged parturition and dystocia, neurological disorders, maternal rejection, abnormal milk production by the dam or metabolic acidosis. However, dummy or silly calf syndrome is specific and has been known to occur in Angus, Hereford, Chianina, Brown Swiss and Brahman cattle.
“Mortalities of PSR calves can be greater than 50%”
Dummy or silly calves appear to be normal at calving but lack the instinct to purposefully suckle. The syndrome occurs with calves of any birth weight, size and sex. Often the calves required more than 2 hours to stand up and initiate any suckling behaviour. During this period these calves used limited body energy reserves and their sensitivity to teat contact is low. This condition is substantially aggravated by climatic exposure, eg. cold and/or wet weather and hot conditions.
PSR calves quickly give up searching in the udder area but continue to search elsewhere (eg. legs, flank) for a source of milk until exhausted.
“PSR causes wastage that reduces economic and genetic progress”
If PSR calves have not suckled by 6 hours they often need several experiences at forced suckling to locate a teat and show a sucking reflex. If unassisted both the calf and the dam suffer. The calf becomes hypoglycemic and depending on weather conditions either dehydrated or hypothermic. Neonatal infections may develop depending on the duration of colostrum deprevation and the level of disease challenges.
The udder and teats of the cow may develop anatomical and mechanical problems making the cow less tolerant to suckling. In the absence of suckling, the colostral immunoglobulen levels and the calves ability to absorb Ig declines the longer the delay between birth and suckling. Cows not suckled have a high tendency to retain reproduction membranes increasing the incidence of uterine infection problems.
Results from studies indicate there is a genetic predisposition verifying that the sire and dam are important factors. To lower the incidence of the “dummy or silly” calf syndrome in a breeding herd, beef producers should cull the cows and sires that show a high incidence of the problem. Often on large properties, deaths and wastage occurs without knowing the level and cause of the problem and actually solving the source of the problem.
Cows with poor udders and teat confirmation, poor mothering ability and a history of neonatal losses should be culled. Good nutritional management and shelter are necessary for good herd management and assist the vigour of the dams and calves with sucking problems including the PSR syndrome.
Where there is evidence (checklist) of PSR calves, assistance must minimise energy expenditure (eg. walking and non teat-seeking behaviour). Due to the obvious nature of the problem survival of the calf depends on artificial nursing (eg. bottle feeding or stomach tubing), preferably with high quality colostrum.
“Correcting the problem requires good records, observation and critical actions”
Colostrum is milk produced during the first few days after calving which is reinforced with blood proteins, vitamins and immunoglobulins (Ig). Studies show that mortality of calves with low serum Ig levels (less than 1000mg/dl) in the first 24 hours after birth have twice the death rates of calves with higher Ig levels. Colostrum differs from normal milk in many ways. It is markedly higher in solids, fat, protein vitamins and immunoglobulins and lower in lactose. The amount of solids and Ig’s decline rapidly after a day and by day 4 milk reaches its normal composition.
New born calves are born with very low levels of Ig which are critical to the proper function of the immune system. Colostrum with large amounts of Ig (sometimes called antibodies) is the primary source of Ig for calves. The neonatal digestive system can only absorb large Ig molecules for a limited period of time (approx. 24 hours) after birth so early feeding of colostrum is essential. (Note: during this period the calf’s intestine can absorb other large molecules and bacteria which are absorbed into the calves system).
“It is difficult to over-emphasise the importance of colostrum”
The amount of Ig in colostrum depends on a large number of factors, including the exposure to disease, disease history and the age of the cow. That is, cows tend to produce Ig in response to pathogen (disease) challenges. The greater the number of exposures to disease the greater the levels of Ig. Cows raised on a property will produce colostrum with antibodies specific to the disease challenges on that farm.
Storage can also influence colostrum quality. Colostrum can be refrigerated for only about 1 week before quality (Ig concentrations) declines.
Freezing is the best option for long term storage of small amounts of colostrum. Colostrum may be frozen for up to 1 year without a significant decomposition of immunoglobulins. (Note: Under excellent conditions colostrum has been stored for up to 15 years).
Frozen colostrum in small bottles (1-2 litres) is easily thawed out in warm (not hot) water. Alternatively, colostrum can be thawed out in a microwave using short periods of low power. Thawed out colostrum should be “poured-off” into a second container to minimise hot spots and continuous heating. Colostrum should not be frozen and thawed out more than once.
Insufficient serum Ig concentrations in calves is often due to failure of passive transfer (FPT). Dummy/silly calves are at particular risk of FPT due to insufficient intake of colostrum. Stomach tubing and/or bottle feeding is necessary with PSR calves.
It is preferable for the calf to suckle but if it can’t, stomach tubing, if done carefully is next best offer. With stomach tubing it pays to get some coaching and certainly follow the instructions carefully. Preferably, the calf should be standing with its head in a comfortable position. A pliable tube is gently passed over the tongue, carefully checking the passage of the tube (see *Stomach Tubing Checklist). If the calf begins to cough or vomit milk, stop immediately.
Stomach tubing is only a short term option and should be replaced by foster rearing or bottle/bucket feeding at the earliest opportunity.
Irrespective of the method of feeding, the amount of colostrum the newborn needs to achieve an acceptable transfer of passive immunity depends on several of the following factors:
When the calves are offered colostrum after 6 hours of age, the amount of colostrum should be increased to offset the decline in absorptive efficiency.
“Any delay in colostrum feeding increases the risk of bacterial infection”
When good colostrum is available, feed 2 litres as soon as possible and 2 litres 12 hours later. If the colostrum is sub-quality, use 3 litres at the first feeding and 2 litres, 12 hours later.
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“Absorption of Ig decreases from 100%to 20% in 24 hours”
If the dam or foster cow is not available after feeding colostrum, fresh milk or milk replacer should be fed. Both have advantages and disadvantages.
It is important to feed at a regular time using consistent products and methods (eg. composition and temperature). It is important not to overfeed (ie. 2 litres twice per day) as this leads to bacterial scours, illthrift and poor growth rates.
Artificially reared calves can be weaned early providing they reach weight for age targets (eg. 60kg at 6 weeks) and have been introduced to an early weaning program. Calves need to be familiar with suitable feeds (ie. hay, meals and pellets & particularly water) prior to weaning.
Calves can be weaned when they are rumenating and eating .75 kg of meal/pellets.day. Intakes of meal and hay can be increased to allow suitable growth rates.
Calves with high Ig serum levels have higher feed conversion, growth rates, less scour days and lower death rates than calves with low Ig serum levels.
Poor sucking reflex calves managed correctly do not have physiological side effects or impairments of the syndrome but it is not recommended that they are used or sold as breeding stock. The guidelines on colostrum feeding are relevant and applicable to orphaned and/or normal calves that have been seperated from their dams.
With dummy calves if the sucking reflex is not stimulated it is lost. Whilst poor nutrition can lead to weak calves, good feed management does not reduce the incidence of dummy calves. Poor conditions and abnormal environments accentuate the problem of dummy calves.
The elimination of the dummy calf does not resolve the PSR problem – this requires the correction of the cause, ie. sire and dam factors compounded by poor udder structure and low mothering ability. Avoid purchasing stock from breeding outlets with low key performance indicators in reproduction and herd replacement management.
A Brahman sucking problem calf with signs of the dummy calf syndrome. There was no evidence of instinct to suckle after the neonate was forced to suckle. Suckling problem calves often become confused during teat seeking if the teats are abnormally large or misshapen. This happens more in older Brahman females although heifers with udder oedema and a low maternal instinct can also be a problem.
Sucking problem calves making no attempt to suckle when the dam is confined are classified as dummy calves Forced-suckling and/or tube-feeding during the first 6 to 8 hours of life is important to the survival of the neonate with the dummy calf syndrome.