Recent advances in exploiting goat's milk: quality, safety and production aspects
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Recent advances in exploiting goat's milk: quality, safety and production aspects. Nissim Silanikove , Agricultural Research Organization ( ARO ), Institute of Animal Science, Israel. Gabriel Leitner , The Veterinary Institute, Israel.

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Recent advances in exploiting goat s milk quality safety and production aspects

Recent advances in exploiting goat's milk: quality, safety and production aspects

Nissim Silanikove, Agricultural Research Organization (ARO), Institute of Animal Science, Israel.

Gabriel Leitner, The Veterinary Institute, Israel

Uzi Merin, ARO, Israel; Colin .G. Prosser, Dairy Goat Co-operative (N.Z.) Ltd., Hamilton, New Zealand

.

.

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Herding of goats is thought to have evolved about 10 000 years in persia
Herding of goats is thought to have evolved about 10,000 years in Persia

  • Goat milk, and the cheese made from it, were venerated in ancient Egypt with some Pharaohs supposedly having these foods placed among the other treasures in their burial tombs (Smith, 2006). Goat milk continued to play an important role in human nutrition in areas acknowledged as the cradle of modern civilization (Hatziminaoglou and Boyazoglu, 2004).


Images of ancient iran arsacid parthian dynasty 248 bce 224 ce metalwork
IMAGES years in Persia OF ANCIENT IRANArsacid (Parthian) Dynasty (248 BCE - 224 CE)METALWORK




Silk road goat herd goat s milk is the most widely consumed milk in the world
Silk Road: goat herd BCGoat's milk is the most widely consumed milk in the world



Goats cheese are gourmet food
Goats cheese are gourmet food BC

Italian Cheeses



Recent advances in exploiting goat s milk quality safety and production aspects

What makes goat milk an attractive option BC?

  • High quality source of protein, minerals and vitamins just like cow milk(soy provides protein only)

  • Differs from cow milk

    • Casein protein profile better for infant digestion

    • More medium chain fatty acids, which are easier to absorb

    • Naturally high in bioactives that are important for infant growth and development


Amino acid pattern compared to human milk
Amino acid pattern compared to human milk BC

Goat milk protein has similar amino acid profile to human milk protein

Rutherfurd et al (2008) Int J Food Sci Nutr Jun18


Casein profile of goat milk
Casein profile of goat milk BC

  • Goat casein profile closer to human milk:

  • Low levels of αs1-casein

  • Greater proportion of β-casein

  • Formation of a finer curd - Easier digestion

  • Lower allergenic burden


Fatty acids in goat milk
Fatty acids in goat milk BC

  • More medium chain fatty acids

    • Have anti-viral activity

    • Absorbed more rapidly than other saturated fatty acids

    • Do not form hard stools



Bioactive components
Bioactive Components BC

  • Goat milk is a natural source of bioactive components such as:

    • Nucleotides,

    • Polyamines,

    • Free amino acids

  • These bioactives are all part of the Non-Protein Nitrogen (NPN) fraction of milk

  • They are the subject of increased interest and research


Nucleotides
Nucleotides BC

  • Nucleotides are building blocks of DNA & RNA

  • They play a role in gastrointestinal health, maturation and recovery

  • Considered to be ‘conditionally essential’ for proper development in infants as they cannot synthesize enough for growing tissue

  • Can be added to infant formula

  • Total nucleotide levels naturally higher in goat milk than cow milk (absent in soy)


Recent advances in exploiting goat s milk quality safety and production aspects

Total Nucleotides BC

Prosser et al (2008) Int J Food Sci Nutr 59:123-133


Polyamines
Polyamines BC

  • Essential for intestinal cell growth and development of digestive capacity

  • May help to prevent or reduce sensitisation to food allergens

  • Total polyamine concentration naturally present in goat milk is higher than cow milk


Polyamines1
Polyamines BC

(Prosser et al 2008, Int J Food Sci Nutr 59:123-133)


Free amino acids
Free amino acids BC

  • Important for gut health and immunity

  • Taurine

    • Bile salt formation,

    • Immune function

    • Some infants may become deficient in taurine, so is often added to infant formula

  • Glutamic acid – source of energy for gut

  • Levels of these amino acids naturally higher in goat milk than cow milk


Free amino acids1
Free amino acids BC

Prosser et al 2008, Int J Food Sci Nutr 59:123-133


Nutrient utilisation
Nutrient utilisation BC

  • Studies show that goat milk fat is utilised more efficiently than cow milk fat

    • in animals with short bowel syndrome (Alfrerez et al, 2001)

    • in infants with malabsorption syndrome (Hachelef et al, 1993)

  • May be due to higher amounts of medium chain fatty acids

  • These studies suggest that goat milk could be a useful dietary intervention for human malabsorption syndrome.


Nutrient utilisation1
Nutrient utilisation BC

  • Similar studies suggest mineral uptake from goat milk greater than cow milk

    • Calcium uptake and calcium content of femur, sternum and Longissimus dorsi muscle in rats (Aliaga L, et al 2000; Campos et al, 2003).

    • Uptake and utilisation of iron (Park et al, 1986; Aliaga et al, 2000; Barrionuevo et al, 2002; Alferez et al, 2006), copper (Barrionuevo et al, 2002), zinc and selenium (Alferez et al, 2003) in rats.

    • Sustains high calcium and magnesium uptake in anemic animals (Nestares et al, 2008)

    • Bone mineral density in growing pigs (Murry et al, 1998)

  • Mechanism for this effect is not known


Digestibility
Digestibility BC

  • Studies show goat milk forms a finer curd than cow milk when acidified in the stomach (Jenness 1980, Haenlein 1992)

  • Low αs1-casein is considered a key reason for this (Clark & Sherbon, 2000)

    • NZ goat milk has low αs1-casein

  • Softer curd thought to facilitate digestion

  • Almass et al (2006) confirms that goat milk proteins digested faster than cow milk proteins


Gut health
Gut health BC

  • Good gut health important for digestion and nutrient absorption

  • Infant gut is relatively immature and more ‘leaky’ than adult gut

  • Gut leakiness linked to several disorders, including allergy

  • Does goat milk enhance gut health?


Recent advances in exploiting goat s milk quality safety and production aspects

Healthy gut BC

Normal IntestineNormal permeability

“Leaky Intestine”Increased permeability

Blood

Blood


Recent advances in exploiting goat s milk quality safety and production aspects

Normal diet BC

7 days

+goat milk

7 days

Trial Details

Treatment

Measurements


Treatment heat stress
Treatment = heat stress BC

heat = more leaky

heat + Goat milk = less leaky

Prosser et al, 2004, J Appl Physiol96:650-654


Recent advances in exploiting goat s milk quality safety and production aspects

Control - healthy BC

Indomethacin

+ goat milk

Indomethacin

Intestinal Villi protected by goat milk


Auckland infant growth study
Auckland infant growth study BC

A randomised, double-blind comparison of goat and cow infant formula

Cameron Grant, Barbara Rotherham, Sue Sharpe, Robert Scragg, John Thompson, John Andrews, Clare Wall, Judith Murphy. Dianne Lowry

University of Auckland

Starship Children’s Hospital, Auckland

Sponsored by Dairy Goat Co-operative (N.Z.) Ltd, Hamilton

Published in J Pediatrics Child Health, 41, 564-568



Key conclusions
Key conclusions BC

  • Growth of infants fed goat infant formula is the same as infants fed cow formula

  • Growth of infants fed goat infant formula is similar to breast fed infants

  • Tolerability of goat infant formula is similar to cow infant formula

  • Goat infant formula is a safe and effective source of nutrition for infants


Recent advances in exploiting goat s milk quality safety and production aspects

Relationships between the conditions of goat's milk production and the contents of some components of nutritional interest in Rocamadour cheese. A. Lucas et al SRR, 2008 - France


P morand fehr v fedele m decandia y le frileux srr 2007
P production and the contents of some components of nutritional interest in Rocamadour cheese. A. Lucas et al SRR, 2008 - France.Morand-Fehr, V. Fedele, M. Decandia, Y. Le Frileux: SRR, 2007


Milk fatty acid composition of goats grazing on alpine pasture an et al srr 2006 slovenia
Milk fatty acid composition of goats grazing on alpine pasture: Žan et al., SRR, 2006 - Slovenia


Conclusions
Conclusions pasture: Žan et al., SRR, 2006 - Slovenia

  • Given free choice, consumption of browse material would be higher in goats than in sheep and cattle, re-emphasizing our null hypothesize that the main advantage of goats over other ruminant species in producing milk rich in valuable nutritional sources relates to its unique feeding habit and high digestion capabilities.

  • Goats milk on pasture is naturally enriched in fat soluble vitamins, unsaturated fatty acids and CLA, in addition to being naturally rich in medium-chain fatty acids.

  • Furthermore, goats milk on pasture have an improved profile of medium-chain fatty acids, in comparison to goats fed conventional concentrate-forage diets

  • High-alpine pasture was shown to be more effective than low-land alpine pasture in this regard.

  • Thus, milk from goats feeding on pasture may present an overlooked "treasure trove" with respects to its health promoting lipid profile.

  • However, a deeper understanding of the interactions between lipids and non-lipid components of pasture and milk composition is needed.


Goat in a tree
Goat in a Tree pasture: Žan et al., SRR, 2006 - Slovenia!


Goats on scrubland and woodland
Goats on scrubland and woodland pasture: Žan et al., SRR, 2006 - Slovenia

  • Goats are able to consume as much as 10 g/day of hydrolysable tannins and 100-150 g/day of condensed tannins without evidence of toxicity (Silanikove et al., 1996, SRR).

  • This ability to ingest tannins exceeds the capacity of sheep and cattle, which indeed are not able to survive without considerable supplementation on such grazing land (Silanikove, 2000, SRR; Silanikove et al., 2001, AFST).

  • Detoxification of tannins by goats is based on enzymatic hydrolysis and depolymerization of the ingested tannins (Silanikove, et al., 2001, SRR).

  • Thus, theoretically, large amount of hydrolysable and condensed tannins-derived phenols as well as of other types of phenolic compounds are absorbed from the GIT by browsing goats


Metabolism of phytochemicals
Metabolism of phytochemicals pasture: Žan et al., SRR, 2006 - Slovenia


Goats on scrubland and woodland1
Goats on scrubland and woodland pasture: Žan et al., SRR, 2006 - Slovenia

  • Plants produce an enormous array of secondary metabolites; many of them has biological effects when comsumed by humans.

  • In particular, monoterpens were identified as compounds that greatly influence the aroma of milk.

  • High content of phenols in milk has shown to improve the quality of milk, such as its oxidative stability and the processing efficiency and quality of dairy products.

  • The results of a few recent studies demonstrate the accumulation of various phenolic compounds in the milk of grazing goats).

  • Whereas this proposition is still speculative, in our view, goat milk rich in phenolic compounds derived from the diet represents a ‘treasure trove’ of potential opportunities for developing functional foods


Issue 2 food safety
Issue 2: Food Safety pasture: Žan et al., SRR, 2006 - Slovenia


Food safety
Food Safety pasture: Žan et al., SRR, 2006 - Slovenia

  • When considering food safety, the major aspects usually thought of are:

  • i) Milk as a source of infection by zoonoses (defined as pathogens which may be transferred from an infected animal to humans and thereby causes a disease in the infected humans);

  • ii) Milk as a source of pathogens that produce toxins, thereby, affecting all organisms, including humans;

  • iii) Milk as a source of undesirable substances from the animal’s diet or inappropriate use of antibiotic, disinfecting and cleansing substances, etc.


Food safety1
Food Safety pasture: Žan et al., SRR, 2006 - Slovenia

  • In Europe and the USA, the main regulatory mean to prevent the occurrence of zoonoses and other pathogenic bacteria and their toxins in marketed goat milk is through bacterial count of the raw milk (Pirisi et al., 2007, SRR).

  • Based on the potential pathogenic issues (written review) there is a reason to implement more stringent food-safety control system in the dairy goat industry.

  • Adding the counts of psychrotrophs may be a valuable criterion not only for the evaluation of milk storage conditions, but for the likelihood of its contamination with pathogens.

  • Another feasible means to improve milk hygiene is to include somatic cell count in milk grading in the form of a payment scheme




Recent advances in exploiting goat s milk quality safety and production aspects

Somatic cell count and gross composition as bases phases

for grading milk quality in sheep and goats


Recent advances in exploiting goat s milk quality safety and production aspects

Aim phases: to calculate the losses of milk and cheese loss as

related to the level of subclinical udder infection in a herd.

Elucidated the major factors that influence milk yield and,

consequently, curd yield in Assaf sheep and Saanen and

Shami × Anglo-Nubian goats,


Recent advances in exploiting goat s milk quality safety and production aspects

Quantifying the damage caused by IMI with CNS phases

From data collected in the present study and those published recently

two equations could be developed to calculate milk yield loss and

total curd yield loss.

These equations combine milk loss and reduction in curd yield per liter of

milk in sheep or goats with sub clinical IMI:

Milk yield loss (%) = 100 - [C × 100 + (100-C) × IUY]/100

Total curd yield loss (%) = 100 - [C × 100 + (100-C) × (IUY-ICY × D)]/100

where: C = % uninfected udders;

IUY = percentage to which milk production is reduced

by sub clinical udder infection;

ICY = percentage of curd lost because of sub clinical udder

infection;

D = liters of milk needed to produce 1 kg of cheese

(30 %moister)




Recent advances in exploiting goat s milk quality safety and production aspects

The Negative Feedback Mechanism Flow-Chart: The ARO concept. milk yield

Blue arrows denote flow of signal along the feedback loop, red arrows denote positive effect and black arrows denote suppressive effect





Milking frequency and goats milk production
Milking frequency and goats milk production milk yield

  • Once-daily milking is more of a traditional milking routine for goats in Europe and in Asia Minor, than sheep and cows.

  • The use of this system in goat farms reflect the fact that many of the farmers devote a large proportion of their activities to producing and selling dairy products (mainly cheese), as an important part of their income.

  • Small difference between once-daily and twice-daily milking regimens which were found in low to moderate producing goats relates to a high udder volume of the goat, in particular with large cisternal capacity that allows a continuous drop of alveolar milk and therefore delays the effect of the intramammary feedback inhibition.

  • This between- and within-species variability in response to milking frequency may be explained in light of the plasmin-related MBNF regulatory concept.


My 1932 kg days in milk 365 d fat 3 1 protein 2 7
MY= 1932 kg; days in milk 365 d; fat = 3.1%, Protein = 2.7% milk yield

  • Ideal goat for intensive management - twice a day milking



Recent advances in exploiting goat s milk quality safety and production aspects

Cork 2005 milk yield

Milk quantity:

Yield of milk, fat, total proteins,

casein and curd.

Milk quality:

Internal bacterial contamination,

somatic cell count,

secreted enzymes.


Recent advances in exploiting goat s milk quality safety and production aspects

Cork 2005 milk yield

Bacterial infection may affect

caseinolysis and micelle properties

by three main routes:

1. directly, by secreting extracellular enzymes

different bacteria will cause different "type"

of physico-chemical damage to the milk


Recent advances in exploiting goat s milk quality safety and production aspects

Cork 2005 milk yield

2. activate the host innate immune system

milk from different type of bacteria with similar

SCC will result in similar damage to the milk

3. a combination of 1 and 2


Recent advances in exploiting goat s milk quality safety and production aspects
Model that explains the interrelationships between bacterial infection and deterioration in milk quality

Bacterial infection

Activation of the

innate system

Cellular

response

Lactoferrin

IgA

Oxidatiive response by O2, NO, H2O2,O2

via XO, LPO

SCC; PMN

Plasmin

?

Protein

oxidation

Proteolysis

of casein

Lipid

oxidation


Recent advances in exploiting goat s milk quality safety and production aspects

Cork 2005 infection and deterioration in milk quality

Hypothesis:

CASEINOLYSIS INDEX

Infected gland

~ 3,000,000

Cell depended

Healthy gland

~ 50,000 Cows

~ 300,000 goats and sheep

Bacteria and Cells depended


Recent advances in exploiting goat s milk quality safety and production aspects

The LS Means of CMT and log SCC in uninfected and infected infection and deterioration in milk quality

udders and their different significance level (P [F]).


Recent advances in exploiting goat s milk quality safety and production aspects

Lactose concentration: sheep or goat with one infection and deterioration in milk quality

gland infected with CNS specie and the

contra-lateral being free

Sheep - 25.1%, P < 0.0001

Goat - 11.3%, P < 0.004

Lactose, g/L


Recent advances in exploiting goat s milk quality safety and production aspects
Milk yield (half) of sheep or goat infected with CNS specie in one gland and the contra-lateral being free.Open bars – S; Hatched bars – G


Recent advances in exploiting goat s milk quality safety and production aspects

The ratio in the reduction in milk yield between in one gland and the contra-lateral being free.

goats and sheep in comparison to the ratio of

reduction in lactose concentration


Conclusion
Conclusion in one gland and the contra-lateral being free.

  • The greater reduction in lactose concentration in infected glands of sheep than in goats, explains the higher loss of milk yield in sheep


Recent advances in exploiting goat s milk quality safety and production aspects

Fat concentration: sheep or goat with one gland infected with CNS specie and the

contra-lateral being free

Sheep - 5%, NS

Goat - 0.03%, NS

fat, g/L


Recent advances in exploiting goat s milk quality safety and production aspects

Protein concentration: sheep or goat with one gland infected with CNS specie

and the contra-lateral being free

Sheep - 9%, P < 0.0009

Goat + 2.3%, P <0.07

protein, g/L


Recent advances in exploiting goat s milk quality safety and production aspects

Casein concentration: sheep or goat with one gland infected with CNS specie

and the contra-lateral being free

Sheep - 12%, P < 0.0002

Goat + 0.003%, NS

casein , g/L


Recent advances in exploiting goat s milk quality safety and production aspects

Whey concentration: sheep or goat with one gland infected with CNS specie

and the contra-lateral being free

Sheep + 7.5%, P < 0.07

Goat +11.5%, P < 0.0001

Whey, g/L


Conclusions1
CONCLUSIONS with CNS specie

  • In goats the increase in total protein concentration relates to increase in total whey concentration

  • In sheep the reduction in total protein concentration relates to a decrease in casein concentration, which overweighs the increase in whey concentration


Recent advances in exploiting goat s milk quality safety and production aspects

Proteose-peptone concentration: sheep or goat with one gland infected with CNS specie

and the contra-lateral being free

Sheep + 247%, P < 0.0001

Goat +151%, P < 0.0001

P-p, g/L


Recent advances in exploiting goat s milk quality safety and production aspects

Ca activity: sheep or goat with one gland infected with CNS specie and the

contra-lateral being free

Sheep - 30.1%, P < 0.002

Goat -14.2%, P < 0.002

Ca, mmol


Conclusions2
Conclusions specie and the

  • The basal level of PL activity is higher in sheep than in goats, which explains the higher basal level of proteose-peptones

  • PL activity in infected glands is higher in sheep than in goats, which explain the higher increase in proteose-peptones

  • In sheep, the source of increased PL activity in the infected gland is accelerated conversion of plasminogen to plasmin, whereas in goats the source is external


Recent advances in exploiting goat s milk quality safety and production aspects
Question: How comes that in goats accelerated degradation of casein is not reflected in casein concentration, whereas in sheep it does?

  • Answer: In goats the reduction in casein output (30%) is essentially similar to the reduction in milk yield, whereas in sheep the reduction in casein output (60%) is higher than in milk volume (53%).

  • Thus, both in goats and sheep part of the increased loss in casein yield is related to increased degradation of casein




Recent advances in exploiting goat s milk quality safety and production aspects

CURD FROM HELTHY GLANDS clotting time, Tc (b), in goats


Recent advances in exploiting goat s milk quality safety and production aspects

CURD FROM INFECTED GLAND clotting time, Tc (b), in goats


Recent advances in exploiting goat s milk quality safety and production aspects

AFTER ONE DAY OF MATURATION clotting time, Tc (b), in goats

INFECTED

HEALTHY


Recent advances in exploiting goat s milk quality safety and production aspects

AFTER 3 MONTH OF MATURATION clotting time, Tc (b), in goats

HEALTHY

INFECTED


Recent advances in exploiting goat s milk quality safety and production aspects

52 clotting time, Tc (b), in goats

35

28

2114

0%

0%

50%

50%

100%

100%

SDS PAGE Tricine


Milk production general conclusions
Milk production: General conclusions clotting time, Tc (b), in goats

  • goats appear to be the least affected ruminant species in respect to physiological manipulations (lower milking frequency), IMI and environmental or emotional stresses that reduce milk secretion.

  • These advantages are explained by their unique morphophological and physiological features and the above-described plasmin-related MBNF.


In goat we trust
In Goat we trust clotting time, Tc (b), in goats

Irrespective to our origin, We hope that this lecture provide strong case that the goats dairy industry has a bright future