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Relationship between selected indicators of milk and blood in sheep
Small Ruminant Research Small Ruminant Research 20 ( 1996) 53-57
Relationship between selected indicators of milk and blood in sheep P. Jelinek a,*, S. GajdfiSek a, J. Illek b aUniversiry of Agriculture, Zemt?de’lskciI, 61300 Bmo, Czech Republic h Universi@ of Veterinary Sciences and Pharmacy, Palack&ho I, 61200 Bmo, Czech Republic Accepted 20 April 1995
Abstract Changes in the composition of milk and blood were studied from the seventh to the 170th days of lactation in ten time intervals (i.e. between 9 March and 29 August) in 22 ewes ( 12 of the Cigaya breed, and ten crosses with a 62.5 and 37.5% proportion of the Cigaya and East Friesian breeds, respectively). There were variations in the concentrations of milk constituents, the highest in somatic cell counts ( 153.6%), vitamin A (73.7%) and Cu (62.8%). Variable blood indicators were urea (50.3%), vitamin E (37.9%) and Zn (22.1%). When estimating interrelationships between selected blood and milk indicators, the effect of stage of lactation was not taken into account. The highest correlation coefficients were between urea in blood plasma and milk (r= 0.90+ + ). The correlations between level of milk fat to total blood plasma protein, vitamin E, vitamin A, pH of blood and plasma urea were r= 0.56+ +, r=0.46++,r=0.33++,r= -0.43++,andr=0.33++ , respectively. Mineral levels in milk were less dependent on the metabolic profile of the blood: the most significant relationships were for Cu and Zn in milk. The most important macroelements of milk, Ca and P, were not significantly influenced by nutrition. The relationships between the levels of the majority of minerals in blood plasma and in milk, with the exception of K, were significant. Keywords: Sheep; Blood; Milk; Composition;
Interrelationships
1. Introduction
The production
and composition
of milk
depends
upon how rapidly the cells of the milk gland are capable of withdrawing nutrients from blood, converting them into milk constituents and releasing them into the alveoli. An isotonic equilibrium exists between blood and milk; however, such an equilibrium between individual components of blood and milk does not exist. The cells of the lactating milk gland utilize as much as 80% of the available nutrients for the synthesis of milk from
* Corresponding
author.
0921~4488/96/$15.00 0 1996 Elsevier Science B.V. All rights reserved SSD10921-4488(95)00771-7
blood. The primary precursors of milk constituents are free amino acids, glucose, acetate, fatty acids and acylglycerols, from which milk proteins, lactose and milk fat are produced. Limiting any of these precursors will reduce milk production and change its composition. The most important factors in the feed ration are CP and energy. If the level of nitrogenous substances is high and the proportion of energy low, the level of glucose in the blood is not affected, but urea concentration increases considerably in blood plasma and in milk as a product of the metabolism of nitrogenous substances, and the relationship between these two concentrations of urea is highly significant (Oltner, 1983).
54
P. Jeliner et al. /Small
Ruminant
Giving balanced nutrition to goats was found to reduce the concentration of urea in milk (Cavani et al., 199 1) . The most important changes in milk composition occur during inflammation of the mammary gland, when cells of the secretory epithelium are not capable of utilizing nutrients from the blood, in particular lactose production decrease, the proportion of proteins changes, the content of serum albumin and immunoglobulins increases and the proportion of casein fractions decreases. As lactose in milk is responsible for nearly one third of the osmotic pressure in milk, the decrease in the content of lactose causes the level of Na to increase and simultaneously also that of Cl ions, so that both the ratio of K to Na and of chloride to lactose, indicated as the chlor-sugar number, change considerably. Similar changes can be observed during dietetic, and/or metabolic, disorders caused by unbalanced or poor-quality feed rations. Studies devoted to the effect of production diseases in dairy cows, particularly the effects of rumen acidosis, alkalosis, ketosis, the syndrome of low fat content of milk and methemoglobinemia, on performance and milk quality have explicitly confirmed that there is a close relationship between blood values and milk constituents. The most important factors appearing during these disorders are a reduced fat content during acidosis, a reduction in milk proteins during rumen alkalosis, and a reduction in lactose during all the metabolic diseases studied (Bergamini, 1987). The technological properties of cow milk are also considerably changed during acute acidosis (GajdBSek, 1990). Studies of the relationships between blood values and the composition of milk have been aimed particularly at dairy cows. Only minor attention has been paid to investigations of these interrelationships in sheep or goats. For these reasons this paper was devoted to studies of relationships between the values of the metabolic profile of blood and of milk constituents. The study links up with our investigations of changes in the composition and properties (Jelinek et al., 1990)) the proportion of fatty acids (GajduSek and Jelinek, 1992) and the level of minerals (Jelinek et al., 1993) in sheep’s milk. 2. Materials and methods The chemical composition of milk and blood during the first lactation was studied in 12 sheep of the Cigaya
Research 20 (1996) 53-57
Table 1 Principal blood values in ewes Indicator
Mean
SE
cv
PH Hemoglobin (g dl- ‘) Total protein (g 1- I ) Urea (mm01 1-l) Glucose (mm01 1-l) Na (mm01 1-l) K (mmoll-‘) Ca (mm01 1-l) Inorganic P (mm01 1- ’ ) Mg (mmoll-‘) Zn (Fmoll-‘) Cu (pm01 1-l) Vitamin A ( pmol 1~ ’ ) Vitamin E (pm01 1-l)
7.42 9.94 74.5 1 6.74 3.22 144.39 4.99 2.43 1.56 0.79 17.37 19.27 2.34 8.90
0.01 0.12 0.58 0.28 0.05 0.37 0.05 0.03 0.02 0.0 1 0.38 0.30 0.03 0.28
0.72 13.12 9.03 50.32 17.76 3.08 11.46 15.88 18.75 15.54 22.08 18.65 16.63 37.92
breed and in ten crossbreds with a 62.5% and 37.5% proportion of the Cigaya and East Friesian breeds, respectively. The winter feed ration before 25 April consisted of meadow hay, fodder beets and supplementary pelleted concentrates. After 26 April the ewes were gradually accustomed to grazing, and after 15 May their only feed was grazing with free access to lump salt. The sheep were in good condition during the whole experiment and clinically, including the udder, they were healthy. Milk was sampled from the morning milking on the following days: 9 March (first sampling) ; 12 March; 2 1 March; 5 April; 3 May; 3 1 May; 27 June; 13 July; 14 august; 28 September. Between 25 April and 3 May the sheep were milked twice a day, and from 4 May until the end of the experiment three times a day. The first samples were taken on average on Day 7 (between Days 5 and 9) after lambing, i.e. one sample was taken during nursing from one milking from one half of the udder, and after weaning the lambs on Day 60 from the whole milking. Milk samples were immediately cooled to 8-10°C and were tested within 5 h of sampling. The basic milk constituents, fat, proteins and lactose, were determined on a Multispec infrared analyzer (Multispeck, UK). In addition to total proteins, the levels of casein and of proteins is the milk serum were determined using a ProMilk apparatus (Foss Electric, Denmark). Total solids were determined by weighing after drying at 105°C and ash content was determined by combustion at
P. Jeliner et al. /Small Ruminant Research 20 (1996) 53-57
550°C. After dissolving the ash in HCI, the solution was diluted and Ca, Mg, K, Cu, Zn and Fe levels were determined using atomic absorption spectrophotometry on an Atomspeck apparatus (Hilger, UK). The content of inorganic P was determined in milk spectrophotometrically after coagulation of proteins with trichloroacetic acid, and the content of urea was determined photometrically using Bio-La-Test kits. Argentometric titration was used to determine the concentration of chloride ions and the spectrofluorometric method was used for vitamins A and E. The somatic cell count was determined in each sample using a Fossomatic apparatus (Foss Electric, Denmark) and the activity of acid and alkali phosphatase was determined spectrophotometrically. Blood samples were collected from the jugular vein into heparinized test tubes immediately before the evening milking and the concentration of hemoglobin was determined spectrophotometrically by measuring the amount of hemoglobincyanide using a Specol apparatus (Carl Zeiss, Germany); the pH value was also assessed. Levels of total proteins were determined using the biuret reaction of the Eppendorf photometric line (Eppendorf, UK) ; the levels of Na, K, Ca, Mg, Cu, Zn, inorganic P, urea, and vitamins A and E were determined using the same methods as for milk.
55
When determining the interrelationships between selected blood indicators and milk constituents we did not take into account either the differences between the groups of ewes (Cigaya and East Friesian breeds) or the stage of lactation; this was because of the results of a previous study (Jelinek et al., 1990). The interrelationships were expressed by linear correlation coefficients.
3. Results and discussion Table 1 summarizes the basic statistical characteristics of selected blood indicators. The highest variability for all evaluated blood constituents evaluated was found is urea, which is directly associated with the uptake of nitrogenous substances in the feed and their utilization in relation to the amount of energy in the feed ration (Oltner, 1983). The level of vitamin E also varied considerably, as did levels of microelements in the blood plasma, owing to their varying concentration in feeds. Table 2 summarizes the basic characteristics of selected milk indicators. The average values and variability corresponded with the results of other authors (Ramos and Juarez, 1980; Zygoyiannis, 1984; Juarez
Table 2 Principal milk values for ewes Indicator
Mean
SE
cv
Fat (%) Total protein (%) Caseins (%) Whey proteins (%) Lactose (%) Vitamin A (pmol 1~‘) Vitamin E (pmol 1-l) Urea (mm01 I-‘) Somatic cells ( 1O6 ml ’ ) Acid phosphatase ( pkat 1~ I) Alkaline phosphatase (kkat 1~ I) Ca (mm01 1-l) Inorganic P (mm01 l- I) Mg (mmol I-‘) Na (mmoll-‘) K (mmoll-‘) Zn (@mall-‘) Cu (pm01 1-l) Fe (pm01 1-l) Titration acidity (2.5 mmol H+ 1-l)
5.71 5.35 3.99 1.39 4.70 5.15 6.54 5.45 0.36 0.12 88.12 50.09 34.96 5.28 31.33 21.65 18.15 4.82 9.41 9.4 1
0.16 0.07 0.06 0.03 0.03 0.30 0.25 0.21 0.55 0.01 5.56 0.74 0.58 0.07 0.63 0.47 0.34 0.24 0.15 0.15
38.32 14.14 14.40 20.86 9.35 73.65 48.00 52.26 153.60 18.32 78.76 18.88 20.97 16.53 25.83 27.90 23.64 62.86 51.98 21.03
P. Jeliner et al. /Small Ruminant Research 20 (I 996) 53-57
56
Table 3 Correlation
coefficients
Blood indicators
between values of blood and milk (Part 1)
Milk constituents Fat
-0.43 -0.17 0.56 0.33 0.26 -0.29 0.09 0.26 0.29 0.05 0.02 -0.18 0.33 0.47
PH Hemoglobin Total protein Urea Glucose Na K Ca PI, Mg Zn CU Vitamin A Vitamin E
** ** ** ** ** ** **
** **
* P
** P
Table 4 Correlation
coefficients
Blood indicators
P,, Mg Zn cu Vitamin A Vitamin E
*
P
**
0.14 - 0.03 - 0.18 -0.32 -0.22 0.29 0.27 - 0.07 -0.10 0.19 0.03 0.43 -0.14 -0.34 P
Caseins
Whey proteins
-0.14 -0.13 0.29 0.20 - 0.06 -0.31 -0.14 - 0.03 - 0.09 -0.23 - 0.06 - 0.01 0.14 0.29
-0.10 -0.11 0.38 0.29 -0.00 -0.30 -0.20 0.04 - 0.06 -0.24 - 0.07 0.01 0.20 0.28
- 0.23 0.37 - 0.03 0.11 0.21 -0.40 - 0.03 -0.29 - 0.06 -0.15 - 0.23 * 0.37 - 0.05 0.06 - 0.08 -0.21 - 0.07 - 0.09 -0.11 - 0.04 - 0.02 0.09 0.07 0.26 0.06 - 0.29 0.17 0.40
**
**
**
**
** ** **
*
**
Lactose
** ** ** +* *
** ** **
Vitamin A
Vitamin E
Urea
- 0.38 - 0.01 0.53 0.40 0.19 - 0.52 - 0.26 0.06 0.14 - 0.09 0.02 -0.28 0.17 0.63
-0.44 -0.38 0.44 0.17 0.28 -0.17 0.26 0.36 0.26 0.07 0.00 - 0.22 0.22 0.33
-0.21 0.17 0.40 0.90 0.59 -0.30 -0.17 0.26 0.09 0.35 0.22 -0.37 0.59 0.51
** ** ** ** **
** **
** ** ** ** ** ** **
* **
* ** ** ** ** ** ** * ** ** **
Somatic cell count
Titrat. acidity
-0.24 0.02 0.05 -0.01 0.08 -0.01 - 0.04 0.11 0.05 0.12 -0.01 0.11 0.02 - 0.08
-0.19 - 0.23 0.40 0.34 0.13 -0.29 0.02 0.15 0.02 -0.10 0.02 -0.22 0.21 0.27
* ** ** **
* * **
between values of blood and milk (Part 2)
Acid phosphatase
PH Hemoglobin Total protein Urea Glucose Na K Ca
Total protein
** * ** **
** **
Alkaline phosphatase
- 0.44 -0.16 0.48 0.52 0.48 -0.40 -0.15 0.13 0.19 -0.15 0.15 0.29 0.32 0.64
** ** ** ** **
** ** **
Mineral constituents Na
K
0.10 0.28 ** - 0.02 0.09 - 0.02 -0.33 ** -0.35 ** -0.21 * -0.25 * -0.11 - 0.09 0.0 1 -0.12 0.06
0.45 0.20 -0.33 - 0.20 -0.15 0.06 - 0.03 - 0.09 0.09 0.09 0.25 0.18 -0.19 - 0.20
of milk
** * ** *
*
*
Ca
PI,
Mg
0.05 0.06 0.12 0.22 * 0.16 0.08 0.02 0.24 * - 0.00 - 0.05 0.18 0.09 0.17 -0.23 *
0.20 0.02 0.03 0.10 0.07 - 0.04 - 0.00 0.21 * - 0.07 0.21 * 0.27 ** 0.04 0.14 -0.06
0.22 0.07 0.07 0.30 0.27 -0.14 - 0.24 0.00 -0.23 0.09 0.16 0.02 0.14 0.06
Zn *
** ** * *
0.25 -0.19 -0.29 -0.13 -0.16 0.25 0.07 - 0.06 0.12 - 0.23 0.30 0.35 -0.23 -0.44
CU * **
*
* ** ** * **
0.48 0.31 - 0.45 -0.40 -0.37 0.38 0.11 -0.14 0.16 0.15 0.13 0.22 -0.30 -0.50
Fe ** ** ** ** ** **
* ** **
- 0.20 - 0.04 0.20 0.11 0.21 0.04 0.13 0.14 0.08 0.26 0.14 0.00 0.15 0.33
* *
**
**
et al., 1984; BoroS et al., 198.5). The highest variation of all indicators was for somatic cells in milk, followed by level of vitamin A and concentration of Cu. Values for the metabolic profile of blood plasma had a particularly strong effect on the content of urea in milk. This relationship is proven by statistically significant or highly significant levels of correlation for the majority of the blood criteria studied and urea concen-
tration in milk (Table 3). The highest correlation 9r=0.90+ ‘) was between the urea content in blood plasma and in milk. A virtually linear dependence has also been found for cow milk (Oltner, 1983), as have increased levels of urea in milk during all metabolic disorders of dairy cows (Bergamini, 1987). The second milk constituent which is strongly affected by blood composition is fat. The highest cor-
P. Jeliner et al. /Small
relations were found between the fat content of milk and levels of total proteins of blood plasma, the pH value of blood, and the amount of vitamin E. Despite the fact that the health of the udder has the strongest effect on the concentration of lactose, significant and highly significant relationships were observed between some blood constituents and the content of lactose in milk. The highest values of correlation coefficients in relation to the content of lactose were found for concentrations of vitamin E, total proteins, pH value of blood, urea and the amount of plasma Na. In addition to nutrition, the levels of vitamins A and E in sheep milk were also considerably affected by the level of metabolic processes during the period of lactation. The reiationship between the level of totat proteins in bIood plasma and the percentage of milk proteins, particularly casein ( r = 0.37 + + ), was also significant. The quantity of mineral substances in milk was relatively less dependent on the metabolic profile of blood plasma (Table 4). The most significant relationships were found for the contents of Cu and Zn in milk, as reported by Miller (1974) and lllek (1987) in cow’s milk. However, the most important macroelements in milk, Ca and P, cannot be greatly affected by nutrition because homeostasis of Ca and P is well regulated and utilizes the reserves contained in bone tissue. This has also been confirmed by the results of our investigations. There were generally significant correlations between the contents of minerals in blood plasma and in milk, with the exception of K, where no relationship has been found. In conclusion, it was confirmed that the level of metabolic processes, as demonstrated using some blood indicators, affects the composition of sheep’s milk and its biological value as has previously been proven in cattle.
ogy (not mamary) from aspects of quality and quantity of bovine milk.). Atti Sot. Ital. Buiatria, XIX,
kozieho a ovCieho mlieka v pribehu laktacie. (Changes in the composition of goat’s and ewe’s milk).
Zivoc. Vyr.. 30: 549-
554 Cavani. C., Bianconi, L., Manfredini, M., Rizzi. L. and Zarri, M.C., 199 I, Effect of a complete diet on the qualitative characteristics of ewe milk and cheese. Small Rumin. Rex, 5: 273-284. Gajdulek,
S., 1990. Dynamika
zmCn vlastnosti mleka pii akutni
acid&e dojnic (Dynamics ofchanges of milk properties in cows with acute acidosis). Zivoc, Vyr., 35: 955-962. GajdfiBek, S. and Jelinek, P., 1992. Zmeny v zastoupeni mastnych kyselin tuku ovfiho mleka v prdbehu laktace (Changes in proportion of fatty acids in the fat of sheep milk during lactation). Zivoc. Vyr.. 37: 165-175 Illek,
J., 1987. Vyskyt.
diagnostika,
terapte a prevence karenci
kobaltu, manganu, medi a zinku u skotu. (Occurrence, diagnosis, therapy and prophylaxis of deficiency of cobalt, manganese, copper and zinc in cattle).
Ph.D. Thesis, Universrty of Veterinary
Science and Pharmaceutics, Bmo. Jelinek. P.. GajdBSek, S.. Illek, J., Helanova, 1. and HluSek, J.. 1990. Zmeny zakladmho sloieni a vlastnosti ovEiho mleka v prfibehu lakrace (Changes in basic composition and properties of sheep milk during lactation). ZivoE. Vyr.. 35: 803-815. Jelinek, P., GajdBSek, S. and Illek. J., 1993. Zmeny obsahu mineralnich latek v ovcim ml&e
v prdbehu laktace (Variations
of
mineral content in sheep milk during lactation). Zivoz. Vyr.. 38: 85-96. Juarez, M.. Ramos, M., Gotcoechea. A. and Jimenez-Perez, S., 1984. Main components. nitrogen fractions and mrneral elements of Manchega ewe’s milk. Chem. Mikrobiol. Technol. Lebensm.. 8: 143-146. Miller. J.W.. 1974. Adaptations in zinc metabohsm by lactating
cows
fed a low-zinc practical-type diet. In: Trace Element Metabolism in Animals. Part 2. University Park Press, Baltimore, pp. 550552. Oltner, R.. 1983. Factors affecting certain blood conrtituents and milk urea in Swedish dairy cattle. Ph.D. Thests. Swedish University of Agriculture Sciences, Uppsala. Ramos, M. and Juarez, M.. 1980. The composition of ewe’s and goat’s milk. Bulletin FIL-IDF
No. A-50. Brussels, I9 pp.
D., 1984. Attempts at improving the productivity of
Karagouniko sheep by mdusirial type of crossbreeding. V. Milk
References F.P.,
pp. 89-99
BoroZ. V., Kr?iil, Z. and Stevonkova, E., 1985. Zmeny v zloieni
Zygoyiannis,
Bergamini,
57
Ruminant Research 20 (I 996) 53-57
yield and milk composition of East Friesland X Karogouniko 1987. Rapporti tra patologia (non mamaria)
ed
aspetti quali-quntitativi del latte nella bovina. (Report of pathol-
ewes kept under intensive conditions. Aristoteleio Panepisthonio Thessalonika, 22: 30
pp.
Relationship between selected indicators of milk and blood in sheep P. Jelinek a,*, S. GajdfiSek a, J. Illek b aUniversiry of Agriculture, Zemt?de’lskciI, 61300 Bmo, Czech Republic h Universi@ of Veterinary Sciences and Pharmacy, Palack&ho I, 61200 Bmo, Czech Republic Accepted 20 April 1995
Abstract Changes in the composition of milk and blood were studied from the seventh to the 170th days of lactation in ten time intervals (i.e. between 9 March and 29 August) in 22 ewes ( 12 of the Cigaya breed, and ten crosses with a 62.5 and 37.5% proportion of the Cigaya and East Friesian breeds, respectively). There were variations in the concentrations of milk constituents, the highest in somatic cell counts ( 153.6%), vitamin A (73.7%) and Cu (62.8%). Variable blood indicators were urea (50.3%), vitamin E (37.9%) and Zn (22.1%). When estimating interrelationships between selected blood and milk indicators, the effect of stage of lactation was not taken into account. The highest correlation coefficients were between urea in blood plasma and milk (r= 0.90+ + ). The correlations between level of milk fat to total blood plasma protein, vitamin E, vitamin A, pH of blood and plasma urea were r= 0.56+ +, r=0.46++,r=0.33++,r= -0.43++,andr=0.33++ , respectively. Mineral levels in milk were less dependent on the metabolic profile of the blood: the most significant relationships were for Cu and Zn in milk. The most important macroelements of milk, Ca and P, were not significantly influenced by nutrition. The relationships between the levels of the majority of minerals in blood plasma and in milk, with the exception of K, were significant. Keywords: Sheep; Blood; Milk; Composition;
Interrelationships
1. Introduction
The production
and composition
of milk
depends
upon how rapidly the cells of the milk gland are capable of withdrawing nutrients from blood, converting them into milk constituents and releasing them into the alveoli. An isotonic equilibrium exists between blood and milk; however, such an equilibrium between individual components of blood and milk does not exist. The cells of the lactating milk gland utilize as much as 80% of the available nutrients for the synthesis of milk from
* Corresponding
author.
0921~4488/96/$15.00 0 1996 Elsevier Science B.V. All rights reserved SSD10921-4488(95)00771-7
blood. The primary precursors of milk constituents are free amino acids, glucose, acetate, fatty acids and acylglycerols, from which milk proteins, lactose and milk fat are produced. Limiting any of these precursors will reduce milk production and change its composition. The most important factors in the feed ration are CP and energy. If the level of nitrogenous substances is high and the proportion of energy low, the level of glucose in the blood is not affected, but urea concentration increases considerably in blood plasma and in milk as a product of the metabolism of nitrogenous substances, and the relationship between these two concentrations of urea is highly significant (Oltner, 1983).
54
P. Jeliner et al. /Small
Ruminant
Giving balanced nutrition to goats was found to reduce the concentration of urea in milk (Cavani et al., 199 1) . The most important changes in milk composition occur during inflammation of the mammary gland, when cells of the secretory epithelium are not capable of utilizing nutrients from the blood, in particular lactose production decrease, the proportion of proteins changes, the content of serum albumin and immunoglobulins increases and the proportion of casein fractions decreases. As lactose in milk is responsible for nearly one third of the osmotic pressure in milk, the decrease in the content of lactose causes the level of Na to increase and simultaneously also that of Cl ions, so that both the ratio of K to Na and of chloride to lactose, indicated as the chlor-sugar number, change considerably. Similar changes can be observed during dietetic, and/or metabolic, disorders caused by unbalanced or poor-quality feed rations. Studies devoted to the effect of production diseases in dairy cows, particularly the effects of rumen acidosis, alkalosis, ketosis, the syndrome of low fat content of milk and methemoglobinemia, on performance and milk quality have explicitly confirmed that there is a close relationship between blood values and milk constituents. The most important factors appearing during these disorders are a reduced fat content during acidosis, a reduction in milk proteins during rumen alkalosis, and a reduction in lactose during all the metabolic diseases studied (Bergamini, 1987). The technological properties of cow milk are also considerably changed during acute acidosis (GajdBSek, 1990). Studies of the relationships between blood values and the composition of milk have been aimed particularly at dairy cows. Only minor attention has been paid to investigations of these interrelationships in sheep or goats. For these reasons this paper was devoted to studies of relationships between the values of the metabolic profile of blood and of milk constituents. The study links up with our investigations of changes in the composition and properties (Jelinek et al., 1990)) the proportion of fatty acids (GajduSek and Jelinek, 1992) and the level of minerals (Jelinek et al., 1993) in sheep’s milk. 2. Materials and methods The chemical composition of milk and blood during the first lactation was studied in 12 sheep of the Cigaya
Research 20 (1996) 53-57
Table 1 Principal blood values in ewes Indicator
Mean
SE
cv
PH Hemoglobin (g dl- ‘) Total protein (g 1- I ) Urea (mm01 1-l) Glucose (mm01 1-l) Na (mm01 1-l) K (mmoll-‘) Ca (mm01 1-l) Inorganic P (mm01 1- ’ ) Mg (mmoll-‘) Zn (Fmoll-‘) Cu (pm01 1-l) Vitamin A ( pmol 1~ ’ ) Vitamin E (pm01 1-l)
7.42 9.94 74.5 1 6.74 3.22 144.39 4.99 2.43 1.56 0.79 17.37 19.27 2.34 8.90
0.01 0.12 0.58 0.28 0.05 0.37 0.05 0.03 0.02 0.0 1 0.38 0.30 0.03 0.28
0.72 13.12 9.03 50.32 17.76 3.08 11.46 15.88 18.75 15.54 22.08 18.65 16.63 37.92
breed and in ten crossbreds with a 62.5% and 37.5% proportion of the Cigaya and East Friesian breeds, respectively. The winter feed ration before 25 April consisted of meadow hay, fodder beets and supplementary pelleted concentrates. After 26 April the ewes were gradually accustomed to grazing, and after 15 May their only feed was grazing with free access to lump salt. The sheep were in good condition during the whole experiment and clinically, including the udder, they were healthy. Milk was sampled from the morning milking on the following days: 9 March (first sampling) ; 12 March; 2 1 March; 5 April; 3 May; 3 1 May; 27 June; 13 July; 14 august; 28 September. Between 25 April and 3 May the sheep were milked twice a day, and from 4 May until the end of the experiment three times a day. The first samples were taken on average on Day 7 (between Days 5 and 9) after lambing, i.e. one sample was taken during nursing from one milking from one half of the udder, and after weaning the lambs on Day 60 from the whole milking. Milk samples were immediately cooled to 8-10°C and were tested within 5 h of sampling. The basic milk constituents, fat, proteins and lactose, were determined on a Multispec infrared analyzer (Multispeck, UK). In addition to total proteins, the levels of casein and of proteins is the milk serum were determined using a ProMilk apparatus (Foss Electric, Denmark). Total solids were determined by weighing after drying at 105°C and ash content was determined by combustion at
P. Jeliner et al. /Small Ruminant Research 20 (1996) 53-57
550°C. After dissolving the ash in HCI, the solution was diluted and Ca, Mg, K, Cu, Zn and Fe levels were determined using atomic absorption spectrophotometry on an Atomspeck apparatus (Hilger, UK). The content of inorganic P was determined in milk spectrophotometrically after coagulation of proteins with trichloroacetic acid, and the content of urea was determined photometrically using Bio-La-Test kits. Argentometric titration was used to determine the concentration of chloride ions and the spectrofluorometric method was used for vitamins A and E. The somatic cell count was determined in each sample using a Fossomatic apparatus (Foss Electric, Denmark) and the activity of acid and alkali phosphatase was determined spectrophotometrically. Blood samples were collected from the jugular vein into heparinized test tubes immediately before the evening milking and the concentration of hemoglobin was determined spectrophotometrically by measuring the amount of hemoglobincyanide using a Specol apparatus (Carl Zeiss, Germany); the pH value was also assessed. Levels of total proteins were determined using the biuret reaction of the Eppendorf photometric line (Eppendorf, UK) ; the levels of Na, K, Ca, Mg, Cu, Zn, inorganic P, urea, and vitamins A and E were determined using the same methods as for milk.
55
When determining the interrelationships between selected blood indicators and milk constituents we did not take into account either the differences between the groups of ewes (Cigaya and East Friesian breeds) or the stage of lactation; this was because of the results of a previous study (Jelinek et al., 1990). The interrelationships were expressed by linear correlation coefficients.
3. Results and discussion Table 1 summarizes the basic statistical characteristics of selected blood indicators. The highest variability for all evaluated blood constituents evaluated was found is urea, which is directly associated with the uptake of nitrogenous substances in the feed and their utilization in relation to the amount of energy in the feed ration (Oltner, 1983). The level of vitamin E also varied considerably, as did levels of microelements in the blood plasma, owing to their varying concentration in feeds. Table 2 summarizes the basic characteristics of selected milk indicators. The average values and variability corresponded with the results of other authors (Ramos and Juarez, 1980; Zygoyiannis, 1984; Juarez
Table 2 Principal milk values for ewes Indicator
Mean
SE
cv
Fat (%) Total protein (%) Caseins (%) Whey proteins (%) Lactose (%) Vitamin A (pmol 1~‘) Vitamin E (pmol 1-l) Urea (mm01 I-‘) Somatic cells ( 1O6 ml ’ ) Acid phosphatase ( pkat 1~ I) Alkaline phosphatase (kkat 1~ I) Ca (mm01 1-l) Inorganic P (mm01 l- I) Mg (mmol I-‘) Na (mmoll-‘) K (mmoll-‘) Zn (@mall-‘) Cu (pm01 1-l) Fe (pm01 1-l) Titration acidity (2.5 mmol H+ 1-l)
5.71 5.35 3.99 1.39 4.70 5.15 6.54 5.45 0.36 0.12 88.12 50.09 34.96 5.28 31.33 21.65 18.15 4.82 9.41 9.4 1
0.16 0.07 0.06 0.03 0.03 0.30 0.25 0.21 0.55 0.01 5.56 0.74 0.58 0.07 0.63 0.47 0.34 0.24 0.15 0.15
38.32 14.14 14.40 20.86 9.35 73.65 48.00 52.26 153.60 18.32 78.76 18.88 20.97 16.53 25.83 27.90 23.64 62.86 51.98 21.03
P. Jeliner et al. /Small Ruminant Research 20 (I 996) 53-57
56
Table 3 Correlation
coefficients
Blood indicators
between values of blood and milk (Part 1)
Milk constituents Fat
-0.43 -0.17 0.56 0.33 0.26 -0.29 0.09 0.26 0.29 0.05 0.02 -0.18 0.33 0.47
PH Hemoglobin Total protein Urea Glucose Na K Ca PI, Mg Zn CU Vitamin A Vitamin E
** ** ** ** ** ** **
** **
* P
** P
Table 4 Correlation
coefficients
Blood indicators
P,, Mg Zn cu Vitamin A Vitamin E
*
P
**
0.14 - 0.03 - 0.18 -0.32 -0.22 0.29 0.27 - 0.07 -0.10 0.19 0.03 0.43 -0.14 -0.34 P
Caseins
Whey proteins
-0.14 -0.13 0.29 0.20 - 0.06 -0.31 -0.14 - 0.03 - 0.09 -0.23 - 0.06 - 0.01 0.14 0.29
-0.10 -0.11 0.38 0.29 -0.00 -0.30 -0.20 0.04 - 0.06 -0.24 - 0.07 0.01 0.20 0.28
- 0.23 0.37 - 0.03 0.11 0.21 -0.40 - 0.03 -0.29 - 0.06 -0.15 - 0.23 * 0.37 - 0.05 0.06 - 0.08 -0.21 - 0.07 - 0.09 -0.11 - 0.04 - 0.02 0.09 0.07 0.26 0.06 - 0.29 0.17 0.40
**
**
**
**
** ** **
*
**
Lactose
** ** ** +* *
** ** **
Vitamin A
Vitamin E
Urea
- 0.38 - 0.01 0.53 0.40 0.19 - 0.52 - 0.26 0.06 0.14 - 0.09 0.02 -0.28 0.17 0.63
-0.44 -0.38 0.44 0.17 0.28 -0.17 0.26 0.36 0.26 0.07 0.00 - 0.22 0.22 0.33
-0.21 0.17 0.40 0.90 0.59 -0.30 -0.17 0.26 0.09 0.35 0.22 -0.37 0.59 0.51
** ** ** ** **
** **
** ** ** ** ** ** **
* **
* ** ** ** ** ** ** * ** ** **
Somatic cell count
Titrat. acidity
-0.24 0.02 0.05 -0.01 0.08 -0.01 - 0.04 0.11 0.05 0.12 -0.01 0.11 0.02 - 0.08
-0.19 - 0.23 0.40 0.34 0.13 -0.29 0.02 0.15 0.02 -0.10 0.02 -0.22 0.21 0.27
* ** ** **
* * **
between values of blood and milk (Part 2)
Acid phosphatase
PH Hemoglobin Total protein Urea Glucose Na K Ca
Total protein
** * ** **
** **
Alkaline phosphatase
- 0.44 -0.16 0.48 0.52 0.48 -0.40 -0.15 0.13 0.19 -0.15 0.15 0.29 0.32 0.64
** ** ** ** **
** ** **
Mineral constituents Na
K
0.10 0.28 ** - 0.02 0.09 - 0.02 -0.33 ** -0.35 ** -0.21 * -0.25 * -0.11 - 0.09 0.0 1 -0.12 0.06
0.45 0.20 -0.33 - 0.20 -0.15 0.06 - 0.03 - 0.09 0.09 0.09 0.25 0.18 -0.19 - 0.20
of milk
** * ** *
*
*
Ca
PI,
Mg
0.05 0.06 0.12 0.22 * 0.16 0.08 0.02 0.24 * - 0.00 - 0.05 0.18 0.09 0.17 -0.23 *
0.20 0.02 0.03 0.10 0.07 - 0.04 - 0.00 0.21 * - 0.07 0.21 * 0.27 ** 0.04 0.14 -0.06
0.22 0.07 0.07 0.30 0.27 -0.14 - 0.24 0.00 -0.23 0.09 0.16 0.02 0.14 0.06
Zn *
** ** * *
0.25 -0.19 -0.29 -0.13 -0.16 0.25 0.07 - 0.06 0.12 - 0.23 0.30 0.35 -0.23 -0.44
CU * **
*
* ** ** * **
0.48 0.31 - 0.45 -0.40 -0.37 0.38 0.11 -0.14 0.16 0.15 0.13 0.22 -0.30 -0.50
Fe ** ** ** ** ** **
* ** **
- 0.20 - 0.04 0.20 0.11 0.21 0.04 0.13 0.14 0.08 0.26 0.14 0.00 0.15 0.33
* *
**
**
et al., 1984; BoroS et al., 198.5). The highest variation of all indicators was for somatic cells in milk, followed by level of vitamin A and concentration of Cu. Values for the metabolic profile of blood plasma had a particularly strong effect on the content of urea in milk. This relationship is proven by statistically significant or highly significant levels of correlation for the majority of the blood criteria studied and urea concen-
tration in milk (Table 3). The highest correlation 9r=0.90+ ‘) was between the urea content in blood plasma and in milk. A virtually linear dependence has also been found for cow milk (Oltner, 1983), as have increased levels of urea in milk during all metabolic disorders of dairy cows (Bergamini, 1987). The second milk constituent which is strongly affected by blood composition is fat. The highest cor-
P. Jeliner et al. /Small
relations were found between the fat content of milk and levels of total proteins of blood plasma, the pH value of blood, and the amount of vitamin E. Despite the fact that the health of the udder has the strongest effect on the concentration of lactose, significant and highly significant relationships were observed between some blood constituents and the content of lactose in milk. The highest values of correlation coefficients in relation to the content of lactose were found for concentrations of vitamin E, total proteins, pH value of blood, urea and the amount of plasma Na. In addition to nutrition, the levels of vitamins A and E in sheep milk were also considerably affected by the level of metabolic processes during the period of lactation. The reiationship between the level of totat proteins in bIood plasma and the percentage of milk proteins, particularly casein ( r = 0.37 + + ), was also significant. The quantity of mineral substances in milk was relatively less dependent on the metabolic profile of blood plasma (Table 4). The most significant relationships were found for the contents of Cu and Zn in milk, as reported by Miller (1974) and lllek (1987) in cow’s milk. However, the most important macroelements in milk, Ca and P, cannot be greatly affected by nutrition because homeostasis of Ca and P is well regulated and utilizes the reserves contained in bone tissue. This has also been confirmed by the results of our investigations. There were generally significant correlations between the contents of minerals in blood plasma and in milk, with the exception of K, where no relationship has been found. In conclusion, it was confirmed that the level of metabolic processes, as demonstrated using some blood indicators, affects the composition of sheep’s milk and its biological value as has previously been proven in cattle.
ogy (not mamary) from aspects of quality and quantity of bovine milk.). Atti Sot. Ital. Buiatria, XIX,
kozieho a ovCieho mlieka v pribehu laktacie. (Changes in the composition of goat’s and ewe’s milk).
Zivoc. Vyr.. 30: 549-
554 Cavani. C., Bianconi, L., Manfredini, M., Rizzi. L. and Zarri, M.C., 199 I, Effect of a complete diet on the qualitative characteristics of ewe milk and cheese. Small Rumin. Rex, 5: 273-284. Gajdulek,
S., 1990. Dynamika
zmCn vlastnosti mleka pii akutni
acid&e dojnic (Dynamics ofchanges of milk properties in cows with acute acidosis). Zivoc, Vyr., 35: 955-962. GajdfiBek, S. and Jelinek, P., 1992. Zmeny v zastoupeni mastnych kyselin tuku ovfiho mleka v prdbehu laktace (Changes in proportion of fatty acids in the fat of sheep milk during lactation). Zivoc. Vyr.. 37: 165-175 Illek,
J., 1987. Vyskyt.
diagnostika,
terapte a prevence karenci
kobaltu, manganu, medi a zinku u skotu. (Occurrence, diagnosis, therapy and prophylaxis of deficiency of cobalt, manganese, copper and zinc in cattle).
Ph.D. Thesis, Universrty of Veterinary
Science and Pharmaceutics, Bmo. Jelinek. P.. GajdBSek, S.. Illek, J., Helanova, 1. and HluSek, J.. 1990. Zmeny zakladmho sloieni a vlastnosti ovEiho mleka v prfibehu lakrace (Changes in basic composition and properties of sheep milk during lactation). ZivoE. Vyr.. 35: 803-815. Jelinek, P., GajdBSek, S. and Illek. J., 1993. Zmeny obsahu mineralnich latek v ovcim ml&e
v prdbehu laktace (Variations
of
mineral content in sheep milk during lactation). Zivoz. Vyr.. 38: 85-96. Juarez, M.. Ramos, M., Gotcoechea. A. and Jimenez-Perez, S., 1984. Main components. nitrogen fractions and mrneral elements of Manchega ewe’s milk. Chem. Mikrobiol. Technol. Lebensm.. 8: 143-146. Miller. J.W.. 1974. Adaptations in zinc metabohsm by lactating
cows
fed a low-zinc practical-type diet. In: Trace Element Metabolism in Animals. Part 2. University Park Press, Baltimore, pp. 550552. Oltner, R.. 1983. Factors affecting certain blood conrtituents and milk urea in Swedish dairy cattle. Ph.D. Thests. Swedish University of Agriculture Sciences, Uppsala. Ramos, M. and Juarez, M.. 1980. The composition of ewe’s and goat’s milk. Bulletin FIL-IDF
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