BRAHMAN NEWS JUNE 2015 ISSUE #187 PAGE 36

By Alex Ashwood

Diseases of the newborn calf can cause unacceptable wastage and calf losses reducing weaning rates and farm profit.

Basic information on calf immunity and keeping in touch with new information and developments can assist in minimising disease and improve the survival of calves from birth to weaning.

Survival of calves from birth to 4-6 months and the avoidance of death and wastage due to scours and respiratory infections depends on newborn calves obtaining passive immunity then developing natural immunity.

Calves are born with a total lack of immunity to infectious diseases. Disease fighting immunoglobulins (1g) are not transferred across the placenta from the cow to the developing calf foetus. Whilst active immunity can be obtained from vaccination programs and antibodies produced to fight infection, the initial protection in newborn calves is dependent on the transfer of immunoglobulins (antibodies) from the cow to the calf.

“Passing antibodies from the cow (via colostrum) provides passive immunity”

The colostrum (first milk) produced by the cow plays a fundamental and critical role in enabling the calf to establish a defence mechanism against disease.

IMPORTANCE OF COLOSTRUM

The calf’s immune system does not function effectively until the calf is 4-6 months old. If the calf fails to suckle or for some reason does not receive an adequate amount of colostrum, it must rely on an immature immune system which provides inadequate protection from disease.

Colostrum deprived calves synthesise immunoglobulin from birth but it takes considerably longer (3-4 months) to reach similar immunoglobulin serum levels found in calves fed adequate levels of colostrum.

If the disease challenge is overwhelming and the calf hasn’t ingested sufficient amounts of antibodies via the colostrum the calf will succumb to the disease.

“Colostrum the primary source for immediate passive immunity and protection” 

Calves that do not ingest sufficient amounts of high quality colostrum soon after birth are three times more likely to get sick and five times more likely to die compared to calves that receive sufficient levels of immunoglobulins (lg).

Colostrum provides a preformed source of immunoglobulins which is actively absorbed across the small intestine to provide protection from infection. Part of the antibodies remain in the gut where they can neutralise pathogenic bacteria and help prevent diarrhoea (scours) in the first 3-4 days after birth. For protection from infection the colostrum must be absorbed shortly after birth (Table 1).

Various factors affect the intake and absorption of sufficient antibodies. The efficiency of immunoglobulin intake and absorption is decreased when the antibody level in the colostrum is low. Factors that affect the level of antibody intake and subsequently the level of passive immunity are:

• Low colostrum volume and quality
• Difficult and prolonged calvings
• Poor cow-calf relationships (bonding and mothering)
• Age of the dam (ie heifers or aged cows)
• Low plane of nutrition and body score at calving
• High levels of stress at calving
• General illhealth and diseases of the udder

Whilst factors affecting colostrum quality and the actual absorption of antibodies is complex, there is, however, sufficient knowledge to prevent hypoimmunoglobulinmia (ie low blood levels of immunoglobulins).

QUANTITY & QUALITY OF COLOSTRUM

Cows colostrum contains about 22 percent total solids compared to 12 percent in normal milk. Different breeds have different levels of total solids. Beef cows tend to produce less milk but with a more concentrated colostrum. Colostrum is also a rich source of protein (casein), fat, sugars and vitamins (particularly A & E) which are essential to the nutrition of the newborn calf.

Table 1: Effect of time feeding on total immunoglobulin (lg) absorption of newborn calf.

TIME OF FEEDING (HRS AFTER BIRTH)	PLASMA CONCENTRATION (MG/ML) (HRS AFTER FEEDING)	ABSORPTION (%)
6	52.7	66
12	37.5	47
24	9.2	12
36	5.4	7
48	4.8	6

Note: 

1. Adequate levels of colostrum intake and immunoglobulins absorption helps to protect the whilst it is developing its own immune system. Calves with inadequate levels of serum globulins have a higher incidence of scours, respiratory disorders and bacterial infections (eg joint ill, navel ill).
2. The calf’s ability to absorb antibodies through to gut lining is highest in the first 6 hours following birth dropping significantly at 18-24 hours as the gut lining matures.
3. The intake of immunoglobulins lessens after each feeding and its absorption is reduced quickly after birth.

“A number of factors influence the total amount of antibodies in colostrum”

It cannot be assumed that the immunoglobulin concentration in colostrum is the same in all cows and heifers. Mature cows produce more colostrum of higher quality than heifers and aged cows and there can be considerable differences between individual animals.

The antibody status of calves increases with the amount fed with suitable immunoglobulin serum levels attained when calves are fed 2 litres in the first 6 hours and a further 3-4 litres in the next 6-8 hours. Approximately 100 gms of immunoglobulins are in 2 litres of colostrum.

“Blood serum levels of immunoglobulins increase linearly with the amount of immunoglobulin”

Better quality colostrum (ie colostral with high concentrations of immunoglobulins) improves the antibody and passive immunity status of the calf. Colostrum low in antibodies requires higher levels of intake. However calves fed higher levels of low quality colostrum have less antibodies than calves fed lesser amounts of high quality colostrum.

NUTRITION

Studies (Ohio State University) showed that cows on a high plane of nutrition provided more colostrum with more antibodies than underfed cows.

Researchers in Wyoming found a 10 percent increased incidence of calf deaths and a further 19 percent deaths from scours in calves from dams on low levels of feed in the last trimester of gestation.

Further studies (Colorado State University) examined the level of disease protection provided to calves from heifers at various body condition scores (Table 2). The researchers found that the heifers in better condition produced more colostrum with a higher immunoglobulin content.

Cow-Calf Relationships

Mothering has a major impact on the intake of colostrum. If the calf does not suck within the first 24 hours post calving it will be hypoimmunoglobimemic.

Cows with well-structured udders and teats have been shown to produce better grown calves than cows with poor udder and teat conformation.

Figures 1 and 2 provide examples of good udders with good teat shape and placement. The udder is well balanced with good attachments supporting well placed properly sized and shaped teats with good texture. Bottle teats, long teats and poorly portioned teats cause major problems to the newborn calf (Figure 3 and 4). Udder edema (Figure 5) which is generally more prevalent in heifers, can seriously limit antibody intake due to reduced suckling by the calf.

The poorer mothering ability of heifers compared to aged cows is often compensated by the better udder and teat conformation of heifers.

“Some newborn calves lack the instinctive ability to suck”

Calves that have poor sucking behaviour is a condition called “dummy calf syndrome” or “poor sucking reflex” (PSR). This condition is different to neurological disorders at calving (eg Akabane disease or Pestivirus).

Poor sucking reflex accounts for a high proportion of sucking problems and if not attended to can cause high mortality rates of calves. PSR calves are 

Table 2: Effect of body condition score (BCS) at calving on the interval from calving to standing and level of immunoglobulin(lg) production.

BODY CONDITION SCORE
	3 (VERY THIN)	4 (THIN)	5 (AVERAGE)	6 (GOOD)
Interval from calving to standing (mins)	59.9	63.6	43.3	35.0
Total immunoglobulin (Ig)*	2192	2351	2445	2653

(*concentration mg/dl in serum 24 hours after birth)

Note: The higher immunoglobulin concentrations in the calves was attributed to a combination of higher levels of antibodies, the dams better condition score and increased activity of the calf.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

hypoimmunuglobinemic and like all calves with insufficient intake of colostrum are prone to infection and disease.

“Failed passive immunity is due to the lack of antibody intake and absorption”

PSR has a genetic predisposition, suggesting the influence of the dam, sire or both. Where there is a higher than normal occurrence of PSR it is probable that the sire of the calf or dam are the common factors involved.

“Stress reduces the efficiency of antibody absorption”

Stress due to unfavourable environments (climate and/or surroundings) can impair bonding between the cow and calf and reduce colostrum intake. Extremes in temperature also lessen the efficiency of immunoglobulin absorption.

Heifers are prone to stress particularly if placed in strange surroundings, have disrupted calvings and prolonged, difficult calving which leads to weak calves and poorer “mothering” ability.

Calving Ease

Lengthy, difficult calvings have a significant effect on the cow-calf relationship, particularly the vigour of the calf and the level of immunoglobulin intake (Table 3).

Assisted calves often result in less vigorous calves, the cow is frequently exhausted and with heifers the calf may be abandoned after stressful calvings. Generally if the heifer fails to lick the calf shortly after birth, “mothering” is dramatically reduced.

“Reducing calving difficulties increases colostrum intake and passive immunity”

Calves experiencing prolonged and/or difficult calvings often do not receive sufficient antibodies due to low colostrum intake, lower quality colostrum and reduced immunoglobulin absorption efficiency. Very often the calves suffer from respiratory and metabolic acidosis which reduces the activity of the calf.

Where necessary, early (not premature) calving intervention (obstetrical assistance) results in more vigorous calves, eager to stand and suck and mothers with a higher “mothering” drive than lengthy difficult calvings.

“Calving difficulties decrease the transfer and absorption of antibodies”

With the increased emphasis on frame score and larger cattle, greater attention needs to be given to sires that do not cause prolonged and difficult calvings.

COLOSTRUM SUPPLENTATION

Calves may require an alternative source of colostrum due to a number of reasons:

• The calf is too weak to suckle soon after birth
• The dam has died, the calf is abandoned or the dam does not allow the calf to suckle
• The stress of prolonged and/or difficult calvings reduces the vigour of the calf
• Extreme weather conditions (eg excessive rain) disrupts or delays sucking and bonding
• The cow has poor udder and/or teat conformation, edema, mastitis, blindquarters
• The quantity and quality of colostrum is low due to poor nutrition, low body condition, illhealth and udder diseases (eg mastitis)

Alternative sources of colostrum include fresh and frozen colostrum and commercially available products. When sourcing colostrum from a dairy farm it is essential that no new diseases (eg Johne’s disease) are not introduced to the herd.

The quality of colostrum can be estimated with the use of a hydrometer. A specific gravity of less than 1.05 is associated with low immunoglobulin content.

Colostrum can be delivered by bottle suckling or force feeding using a oesophageal feeder (ie stomach tubing). Care must be taken with stomach tubing to ensure that colostrum enters the rumen or fore stomach and not the windpipe and lungs.

STOMACH TUBING CHECKLIST

• Use a firm but pliable tube which is rounded on the end and has no rough edges (note: oesophageal feeders are available commercially).
• Tilt the calf’s head backwards and gently direct the tube over the calf’s tongue to the back of the throat.
• Check that the tube has entered the oesophagus not the wind pipe by gently feeling the tube in the windpipe.
• Once the tube is well placed in the oesophagus at the bottom of the throat release the fluid into the fore stomach.

“Care needs to be taken when thawing out frozen colostrum”

Rapid defrosting and stirring denatures the protein antibodies. The two methods recommended for thawing colostrum are:-

• Thaw the container of colostrum (1-3 Litres) in warm water 110oF (approx. 44oC) and gently stir every 5 minutes.
• Use a microwave set at no more than 60 percent power, agitating gently frequently to ensure even warming and thawing.

Note: Both procedures take about 40 minutes and at the completion of thawing the colostrum should be approximately 104oF (40oC).

Table 3: Effect of calving difficulty on serum concentration level, calf activity and mothering.

CALVING DIFFICULTY SCORE
	1	2	3
Calf Activity (minutes from calving to standing)	39.5	50.9	84.3
Immunoglobulin (IgG) intake (mg/dl)	2401	2191	1918.5

Note: 1 = unassisted, 2 = assisted after one hour of labour and easy pull, 3 = assisted after 1 hour of labour and difficult pull.

BOTTOM LINE

Passive immunity to prevent infection and disease is gained by the post natal calf through colostral antibodies. The colostrum contains immunoglobulins that are absorbed from the intestine into the bloodstream by the newborn calf providing partial immunity.

If the newborn calf is seriously challenged by infection and/or does not receive sufficient high quality colostrum in the first 18-24 hours after birth the calf is at risk of serious infections and disease (eg scours, septic arthritis, pneumonia).

Passive immunity provides early protection (4-6 weeks) whilst the calf is developing natural immunity. Immunity is not gained until 4-6 months after birth and subject to potential of disease challenges the calf may need vaccination for a specific disease (eg blackleg). The necessity for an ongoing strategic vaccine program will depend on the threat/risk of a specific disease to the herd.

Factors that enhance the intake and absorption of sufficient levels of immunoglobulins are:

• Adequate levels of nutrition of the dam ensuring that cows have a BCS of 5-6 at calving. Heifers need to be in better body condition than cows.
• Avoid using bulls and dams that have a genetic predisposition to poor sucking and mothering. 
• Select sires and dams that limit the incidence of calving difficulties and ensure heifers are mated to bulls that produce small but growthy calves.
• Ensure heifers are mated at the correct weight for age.
• Avoid stressful calvings and environments that disrupt and prolong calvings.
• Provide early (not premature) calving intervention with difficult calvings to prevent weak calves which are reluctant to suckle.
• Where low intakes of colostrum are suspected (poor mothering ability, dystocia, poor udder and teat structure) be prepared to provide 2 litres of colostrum in the first 6 hours and a further 3-4 litres in the next 6-8 hours.
• Carefully source, store and thaw out good quality colostrum.
• Provide clean calving areas to minimise the environmental load of ever present pathogens.
• Isolate infected stock which shed vast quantities of infectious organisms.

Financial and genetic losses due to disease and death of newborn calves is a concern to beef producers. This article outlines some of the factors that impact on passive immunity, colostrum quality and the transfer of sufficient levels of antibodies (immunoglobins) via the colostrum from the dam to the calf.

“Early protection from disease comes from passive immunity provided by colostral immunoglobulins”

CHECKLIST WHEN FEEDING COLOSTRUM
ITEM	DO	DON’T
Colostrum Feeding	Feed first feeding of colostrum as soon as possibleUse fresh colostrum if availableIf colostrum is good quality, feed 2 litres at the first feedingFeed 3 litres at the first feeding if the calf is large, has not consumed colostrum in 6 hours and if in a difficult climate/environmentStomach tube first feeding if calf can’t consume 2 litres	Use colostrum from cows with leaking teats or mastitisAvoid storing colostrum that contains blood or is low qualityDo not use faulty or dirty equipmentSource colostrum from diseased cows (eg Johne’s)Use thin-watery colostrum, especially from heifersUse abnormal colostrum
Colostrum Quality	Use only good quality colostrumSave good quality colostrum in 1-2 litre bottlesThaw out colostrum carefully to preserve antibodies	Place frozen colostrum in hot water or heat in a microwave under high powerUse poor quality colostrum at first two feedingsUse colostrum that contains antibiotics
Other Management Tasks	Dip navel with tincture of iodine as soon as possibleIsolate the calf in warm dry surroundingsContinue to feed sufficient intakes of consistent qualityCheck for bacterial infection and dehydration	House calves in wet/drafty surroundingFeed using poor techniques at erratic timesOverfeed the calf Use antibiotics without vet consultation

FURTHER READING

“Desirable and Undesirable Udders” – ABBA Brahman News, March 2008

“Poor Suckling Reflex” – ABBA Brahman News, September 2004

“Anatomy and Endocronology” – ABBA Brahman News, December 2011

“Reproduction – Herd Health” – ABBA Brahman News, September 2011

“Calving Ease and Dystocia” – ABBA Brahman News, March 2010

“Immune Systems and Vaccination” – ABBA Brahman News, December 2014