on effects of stage of lactation and subclinical mastitis on milk quality in goats
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On effects of stage of lactation and subclinical mastitis on milk quality in goats. Nissim Silanikove Biology of Lactation Lab, Agricultural Research Organization, The Volcani Center, Israel Uzi Merin Department of Food Science, Agricultural Research Organization, - PowerPoint PPT PresentationTRANSCRIPT
On effects of stage of lactation and subclinical mastitis on milk quality
in goats
Nissim SilanikoveBiology of Lactation Lab,
Agricultural Research Organization,The Volcani Center, Israel
Uzi MerinDepartment of Food Science,
Agricultural Research Organization,The Volcani Center, Israel
Gabriel LeitnerKimron Veterinary Institute, Israel
Milk quality:fat, total proteins, casein, curd and are affected by
intramammary Infection and stage of lactation
Cheese quality:yield, structure, smell, flavor,
shelf life and all these factors are subjected to the effect ofintramammary Infection and stage of lactation
Traditional farming
1. Along the lactation different products are produced2. Milk from clinically infected
glands is discarded
Modern dairy forming
1. Animals are milked while at different stages of lactation2. A large number of glands are
infected with a variety of bacteria
Animal model built on the gland level
One udder-half identified with CNS species and the contra-lateral being free of bacteria
+ -
S. caprae S. chromogenes S. epidermidis S. simulans S. xylosus
+ -
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
0.0
0.5
1.0
1.5
2.0
Uninfected Infected
Milk
yie
ld (k
g/da
y)
1 2 3
Curd firmness(volts)
Clotting time(sec)
Cork 2005
Curd yield and clotting time of goat milk from infected vs. uninfected udder-halves
Uninfected
0
100
200
300b P < 0.02
Clo
tting
tim
e (s
)
200
210
220
230
240a
P < 0.0001
Cur
d yi
eld
(g/L
; wet
bas
is)
Infected
0.5
3.5
Milk
K/d
ay
Day in milk
SCC
(100
0)
1000
100
Milk yield and SCC along the lactation of uninfected glands
0.5
3.5
Milk
(K/d
ay)
Days in milk
SCC
(x 1
000)
1000
100
Milk yield and SCC along the lactation of infected glands
Parameter MLG-Fb MLG-Ib LLGb R2 P [F]
DIM 129 ± 15.9b 121 ± 6.3b 269 ± 4.8a 0.476 <0.001
Milk (L d−1) 3.07 ± 0.2a 2.64 ± 0.16b 0.80 ± 0.2c 0.542 <0.001
SCC (×1000) 292 ± 46c 2861 ± 642b 6274 ± 710a 0.253 <0.001
Fat (g L−1) 33.2 ± 2.4b 36.0 ± 1.9b 50.5 ± 1.9a 0.303 <0.001
Protein (g L−1) 32.0 ± 2.8b 34.7 ± 2.2b 56.6 ± 2.2a 0.380 <0.001
Casein (g L−1) 23.1 ± 1.9b 23.3 ± 1.6b 40.3 ± 1.5a 0.423 <0.001
%Caseinc 74.16 ± 0.6a 68.26 ± 0.84c 70.59 ± 0.80b 0.157 <0.001
Lactose (g L−1) 47.2 ± 0.4a 44.1 ± 1.0b 37.0 ± 1.0c 0.266 <0.001
RCT (s) 443 ± 50c 621 ± 30b 2107 ± 230a 0.236 <0.001
CF-60 (V) 8.57 ± 1.91a 1.26 ± 2.77b 5.2 ± 1.30b 0.094 0.038
Days in milk (DIM), milk yield, SCC, gross milk composition (fat, protein, casein, lactose), rennet clotting time (RCT) and curd firmness (CF) of goats’ milk for mid-lactation, bacteria-free (MLG-F), mid-lactating, infected (MLG-I), and late-lactation, bacteria-free (LLG)a.
* Many of the animals with subclinical chronic infection are not noted because there are no recognizable symptoms and the milk appearance is normal
* End of lactation goats show increased SCC regardless of IMI
** Routine milk testing such as CMT on the animal side or more advanced techniques like the sophisticated cell counters allow the identification of subclinically infected animals close to the occurrence of the infection. However, it is laborious and/or require special equipment to perform
*** On-line computerized milking systems are designed in part to overcome these conditions and to apply genuine real-time data acquisition on individual animals, including milk yield and conductivity
Healthy gland ~ 50,000 Cows
~ 300,000 goats and sheep
Infected gland ~ 3,000,000
CASEINOLYSIS INDEX
Cell depended
Bacteria and Cells depended
Low quality curd
100
1000
10000
0 5 10 15 20 25 30 35 40
Curd firmness (Cf)
correlation ( r= -0.4(
Log SCC and Cf of curd of goat milk at mid lactation with and without IMI and at the end of lactation
without IMI- SCC is not the best predicting variable for milk quality
Log
SCC
Clotting time and curd firmness
Curd firmness(V)
Clotting time (sec)
Bacteria
6.58±0.2 650±63 NBF
1.02±0.3 2490±340 Strep.
3.80±0.8 1255±468 CNS E. coli 3.28±0.7 1078±193 S. aureus
100
1000
0 1 2 3 4 5 6
Strep. dysgalactiae S. aureus
Curd firmness (A30 Optigraph)
log
Som
atic
Cel
l Cou
nt
Strep. dysgalactiae
Staph. chromogenes
Healthy Infected
Correlations and respective probability (P[r]) for cows, goats, and) sheep between levels of protein, casein, (protein + fat), % casein and lactose, SCC, and log SCC, and curd firmness (CF) of milk:
– ∗ P > 0.001; – ∗∗ P > 0.05; NS – not significant
Low quality curd
1
2
3
4
5
6
0 5 10 15 20 25 30 35 40
% L
acto
se
Lactose lower than 4%
% lactose and Cf of curd of goat milk at mid lactation with and without IMI and at the end of
lactation without IMI
Curd firmness (Cf)
0
1
2
3
4
5
6
0 5 10 15 20 25 30 35
Curd firmness (V)
Per
cent
lact
ose
in m
ilk
Sheep Goat Cow
Influence of percent lactose in milk on curdfirmness as measured by the Optigraph
* It was found that lactose content in milk is the best indicator for milk quality for cheese making. * It is already implemented in Afilab (Kibutz Afikim, Israel) On- line FTIR-based recording system in dairy cows milking parlors The system enables to separate on-line milk unfit for cheese making from milk suitable for cheese on the pipe-line between the milking parlor and the tank during milking and store them in separate tanks
* Feasibility test of the system for small ruminants was conducted The system will enable direct and cheap daily identification of animals with milk unsuitable for cheese making and perhaps to separate it as already done with cows
0
10
20
30
40
50
60
Uninfected Infected
SheepGoat
PL a
ctiv
i ty, u
nits
/mL
Plasmin activity: sheep or goat with one gland infected with CNS specie and the
contra-lateral being free Sheep + 195%, P < 0.0003Goat + 73%, P < 0.0007
SDS PAGE Tricine
0% 0% 50% 50% 100% 100%
52
35
28
2114
Preparation Healthy (10) S. chromogenes (4) E. coli (7)
Str. dysgalactiae (5)
p–p 160 ± 50 180 ± 70 360 ± 40 320 ± 60FE 7.2 ± 1.2 8.4 ± 1.4 23 ± 2.0 27.3 ± 2.2% FE of p–p 4.5 4.4 6.3 8.4
Amounts of p–p and FE obtained from milk samples.Numbers in parenthesis indicate the number of glands tested. Proteose peptone determined using the Bradford (1976) method, FE estimated as the area under the OD280 values of the FPLC chromatogram; values are given as mean and SD in mg L−1.
Dose–response effect of the addition of fraction E (FE) from milk obtained from healthy glands (open bars) and from Str. dysgalactiae-infected glands (hatched bars) to milk from healthy glands on rennet clotting time and curd firmness, as assessed using the Optigraph.
The effect of addition of up to 5 mg fraction E (FE) to 10 mL of milk obtained from healthy or Str. dysgalactiae-infected glands, in the presence of calcium ions, to milk from healthy glands, on rennet clotting time (RCT) and curd firmness (CF), as assessed using the Optigraph.
Anti-Lactogenic hormones
e.g., Cortisol, Estrogen
Lactogenic hormones e.g., GH,
Prolactin
alveoli
PA
PL
PLG
Frequent milking or suckling
Reaction type 1
Reactiontype 2
12
Blood
Lumen
External effects:Milking, suckling, bacterial invasion
Milk stasis or bacterial invasion
Cork 2005
Bacterial infection
Cellularresponse
Cytokines, SCC (PMN)
Plasmin
SCC = somatic cell countPMN = polymorphonuclear
Caseinolysis
Oxidatiive response by
NO-derived NO2 radical
Lipidoxidation
Activation of the
innate system
Proteinoxidation
SCC is a good reference for milk quality if we compare good quality (300000 cell/ml) with low quality one (1 million cells and above). Milk for cheese production and caseinolysis are bacteria species-dependent and are poorly predicted by SCC
Bacteriological status
Carotene destruction,nMsec-1
FRAP, Ascorbic acid, µM
Ntyr, nMg-1 Lpx,mEqv g-1
Non-infected 669 +121a 413 + 27a 143 + 11a 110 + 47 1.3 +0.3a
Infected with coagulase-negative staphylococci
2006 + 215b 305 36b 91 + 7b 170 + 41 2.8 + b
Effect of subclinical mastitis on oxidative, antioxidative and formation of oxidized substance
in milk
subclinical mastitis is associated with significant losses in milk yield and quality for cheese production. Milk of subclinically infected glands is subjected to considerable NO-derived oxidative stress, which only moderately impose nitrosative stress on milk proteins. However, it is associated with significant loss of milk antioxidant capacity and vitamin C levels, which are particularly high in goats.
Thus, it is concluded that subclinical mastitis induces unfavorable changes in milk quantity and composition, which affects considerably both to the farmers and the dairy sector that depend on goat’s milk.