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Teresa Bombik1, Antoni Bombik2, Krystyna Tyszuk2, Leon Saba3 ©
1 Department of Reproduction and Animal Hygiene, 2 Department of Agricultural Experimentation, University of Podlasie, Siedlce, Poland 3 Department of Animal Hygiene and Environment, University of Life Sciences, Lublin, Poland
EFFECT OF DRY PERIOD AND INCREASING COW LACTATION ON THE CONCENTRATION OF SELECTED MICROELEMENTS
IN SERUM BLOOD
The objective of the work was to assess and compare zinc, copper and iron concentrations in the blood serum of dry and lactating cows. An experiment was conducted for eight clinically healthy cows which were housed under good environmental and nutritional conditions. The average milk yield per one cow was approximately 5400 litres.
Blood of the cows was sampled 6 times, viz. in the dry period - every two weeks (2nd, 4th and 6th week) and in the lactation period - at one-month intervals (1st, 2nd and 3rd month). Microelement concentrations in blood serum were determined by atomic absorption spectrophotometry. The results obtained were analysed statistically.
Concentrations of selected elements in blood serum of cows depended on their physiological status. A lower and statistically significant copper and iron level was demonstrated in the blood serum of lactating cows. The lowest and statistically significant concentration of microelements determined in blood serum was found in the 1st week of cow lactation. Deficiencies in supplementing cows with copper and zinc in the Podlasie region examined should be supplemented by applying mineral mixtures in cow rations, the composition of which should be developed on the basis of contents of these elements in the soil, plants and cow organisms.
Key words: cows, dry period, lactation, blood, microelements
Introduction. Microelements, which are trace elements, play a number of important roles in animal bodies (Kabata-Pendias and Pendias, 1999). According to Ruszczyc (1983), their optimal supply in feeding rations assures proper growth and development of animals as well as high performance. In dairy cow nutrition there are most frequently applied on-farm feeds, which, when accompanied by local deficiency of mineral elements in the soil, results in reduced contents of the elements in plants and the animal organism (Saba et al., 2000; Bis-Wencel, 2001; Bombik et al., 2004; Gorski et al., 2005).
According to Rutkowiak (1987), over half of non-infectious diseases recorded in cows is represented by metabolic disorders following from, among others, an inappropriate level of mineral elements. Thus, as indicated by Staufenbiel and Gelfert (2004) and Whitaker et al. (2005), the necessity arises to carry out periodical
© Teresa Bombik, Antoni Bombik, Krystyna Tyszuk, Leon Saba, 2008
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diagnostic monitoring of diary cattle herds because the monitoring plays a significant role in disease prophylactics and enables obtaining high values of economic indices.
The objective of the research was to assess and compare contents of selected microelements in cows' blood serum during the dry period and increasing lactation.
Material and methods. An experiment involved cows of Polish Holstein-Frisian breed, black and white line, kept on a farm situated in the southern Podlasie region. The barn where 26 cows were housed was a bedding (shallow) kind of building with tie stall system (cows stand in individual stalls and are tied by a neck chain). There were no contagious or invasive diseases on the farm. The average milk yield per cow per a 305-day lactation period was about 5400 litres.
Feeds applied in animal feeding and their amounts covered energetic and protein requirements of the cows and met the requirements of the Livestock Nutrition Norms (Rys, 1998). Grazing, supplemented by maize silage, hay and barley straw, was the basis of cow feeding in the summer. During the winter period cows were offered corn silage, hay and barley straw. In both the summer and winter the cows received, depending on their milk performance, a supplement of an on-farm concentrate mixture.
The research under strict study conditions included 8 clinically healthy cows characterised by similar breeding and production parameters. Cow blood, sampled before feeding (in the morning), was taken from the external jugular vein. Sampling was performed six times, that is every two weeks during the period of drying off (2nd, 4th and 6th week), and at one-months intervals during the lactation period (1st, 2nd and 3rd month). Concentrations of selected microelements (zinc, copper and iron) in blood serum were determined by atomic absorption spectrophotometry method using an Unicam 939 AA spectrometer.
The study results obtained were subjected to statistical analysis (Oktaba, 1980; Tr^towski and Wojcik, 1991) which included calculating the arithmetic mean (x) and coefficient of variation (V%). Also, contents of selected mineral elements (zinc, copper and iron) in the blood serum of cows were subjected to two-way analysis of variance for the hierarchical classification, according to the following formal model:
yijl = m + ai + b(a)ij + eijl,
where:
yijl - value of a characteristic examined for the lth cow (n = 8) in the ith group and at the jth date;
m - grand mean;
ai - effect of the ith group (i = 1, 2, ..., a, a = 2);
b(a)ij - effect of the jth date within the ith group (j = 1, 2, ., b, b = 3);
eijl - error term (eijl ~ N(0;o)).
Significance of differences between means was checked using Tukey's test at the probability level of 0.05.
Results of the research. Results of analyses of selected microelements in the blood serum of cows according to their physiological status are presented in tables 13.
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Table 1
Average zinc content in cow blood serum (^mol/dm3)
Physiological groups Statistical measures Blood sampling dates (weeks, months) Mean for groups
Dry cows x V% 2nd week 4th week 6th week 16.08 a
15.84 a 16.15 b 16.26 b
17.2 18.6 14.8
Lactating cows x V% 1st month 2nd month 3rd month 15.91 a
15.80 a 16.19 b 15.73 a
29.1 27.7 30.5
a, b - means for sampling dates (in rows) and for groups (in columns) followed by the same letter do not differ significantly (P<0.05).
The average zinc concentration in the blood serum of cows ranged from 15.73 to 16.26 p,mol/dm3 (table 1). The concentration of this element for the group of dry cows increased in successive weeks of blood sampling, significant differences (15.84 and 16.15 ^mol/dm3) being found only between the 2nd and 4th week of drying off. In the group of lactating cows the highest zinc concentration, the values differing significantly from the 1st and 3rd month, was found in the 2nd month of lactation (16.19 p,mol/dm3). No significant differences between the average zinc concentrations were found for the physiologic groups examined.
The physiological zinc level for cattle cited by Winnicka (1997) should approximate 15.3 p,mol/dm3. In contrast, Bednarek (1998) recommends values ranging from 15.4 to 30.8 ^mol/dm3. Taking into consideration the above recommendations, it should be noticed that the zinc concentration in the cows of the herd examined was within the lower reference limit.
Table 2
Average copper content in cow blood serum (^mol/dm3)
Physiological groups Statistical measures Blood sampling dates (weeks, months) Mean for groups
2nd week 4th week 6th week
Dry cows x 9.69 a 9.98 b 10.10 b 9.92 b
V% 17.7 12.0 19.2
1st month 2nd month 3rd month
Lactating cows x 9.37 a 9.78 b 9.61 b 9.59 a
V% 24.4 30.2 21.8
Explanations: as in table 1.
The average copper concentration in the blood serum of cows assumed extreme values of 9.37-10.10 ^mol/dm3 (table 2). In the group of dry cows the concentration of this element increased in successive weeks of blood sampling, significant differences being between the 2nd and 4th week of drying off. In turn, in the group of lactating cows, the lowest copper concentration was found in the 1st month of lactation (9.37 p,mol/dm3), significant differences occurring from the 2nd and 3 rd month). A significantly higher copper concentration was observed for the dry cows.
The value of 18.84 ^mol/dm3 is a physiological copper level in cattle blood serum (Winnicka, 1997). In this study, the copper concentration in cow serum at all
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the blood sampling dates was very low, independent on the cows' physiological status.
Table 3
Average iron content in cow blood serum (^mol/dm3
Physiological groups Statistical measures Blood sampling dates (weeks, months) Mean for groups
2nd week 4th week 6th week
Dry cows x 27.15 a 27.80 a 29.59 b 28.18 b
V% 21.8 10.8 11.2
1st month 2nd month 3rd month
Lactating cows x 25.11 a 26.76 b 26.40 b 26.09 a
V% 44.1 29.6 26.6
Explanations: as in table 1.
The average iron content in the blood serum of cows ranged from 25.11 to 29.59 p,mol/dm3 (table 3). In the group of dry cows, the concentration of this element increased at successive blood sampling dates, significant differences occurring between the 4th and 6th week of drying off. In the group of lactating cows, the lowest iron concentration was found in the 1st month of lactation (25.11 ^mol/dm3), significant differences being recorded from the 2nd and 3rd month. Analysis of variance showed significant differences in the blood serum iron level between dry (28.18 p,mol/dm3) and lactating cows (26.09 p,mol/dm3).
Iron deficiency in adult ruminants occurs very rarely and, in practice, is connected with pathological conditions. Due to substantial fluctuations between individuals, the appropriate iron level in cattle blood serum is set as falling within the range of 12.2-38.5 ^mol/dm3. The iron concentration in the blood serum of cows examined was within these limits.
Conclusions
1. The concentration of selected microelements in the cow blood serum depended on their physiological status. Lower and statistically significant copper and iron contents were found in the blood serum of lactating cows.
2. In the group of dry cows increased zinc, copper and iron contents were observed at successive blood sampling dates.
3. The lowest and statistically significant concentrations of microelements determined in blood serum were recorded in the 1st week of lactation.
4. Deficiencies in supplementing cows with copper and zinc in the Podlasie region examined should be supplemented by applying mineral mixtures in cow rations. Their composition and percentage of ingredients should be developed on the basis of contents of these elements in the soil, plants and cow organisms.
References
1. Bednarek D., 1998: Rola cynku w procesach odpornosciowych u zwierz^t. Medycyna Wet., 44(2), 92-95.
2. Bis-Wencel H., 2001: Rozpoznanie i zapobieganie niedoborom mineralnym u przezuwaczy w rejonie poludniowo-wschodniej Polski. Rozpr. hab., 100, AR, Lublin.
3. Bombik T., Bombik E., Saba L., Trawinska B., 2004: Zaleznosc mi^dzy wyst^powaniem miedzi w glebie, paszach i organizmie krow. Zesz. Nauk. AR, Wroclaw, Zoot., LI, 37-43.
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4. Gorski K., Saba L., Bombik T., Bombik E., 2005: Poziom wybranych mikro-elementow (Fe, Cu, Zn) w glebie, paszach i surowicy krwi krow w rejonie poludniowego Podlasia. Rocz. Nauk. PTZ, 1, 2, 309-318.
5. Kabata-Pendias A., Pendias H., 1999: Biogeochemia pierwiastkow sladowych. PWN Warszawa.
6. Oktawa W., 1980: Elementy statystyki matematycznej w doswiadczalnictwie, PWN, Warszawa.
7. Ruszczyc Z., 1983: Znaczenie i rola mikroelementow w zywieniu zwierz^t. Zesz. Probl. Post. Nauk Roln., 434, 1-11.
8. Rutkowiak B., 1987: Zaburzenia trawienne i metaboliczne w stadach krow mlecznych. PWRiL, Warszawa.
9. Rys R., 1998: Normy zywienia bydla i owiec systemem tradycyjnym. Inst. Zoot., Krakow.
10. Saba L., Bombik T., Bombik A., Nowakowicz-D^bek B., 2000: Niedobory mineralne u krow mlecznych. Medycyna Wet., 56(2), 125-128.
11. Staufenbiel R., Gelfert C.C., 2004: Metabolic Profile Test as a Managament Tool in Dairy Herds. The 5th Middle-European Buiatrics Congress, Hajduszoboszlo, 271.
12. Tr^towski J., Wojcik A.R., 1991: Metodyka doswiadczen rolniczych. WSRP, Siedlce.
13. Whitaker D.A., Macrae A.I., Burrough E., 2005: Nutrion, Fertility and Dairy Herd Productivity. Catle Practice, 13, 27-32.
14. Winnicka A., 1997: Wartosci referencyjne podstawowych badan laboratoryj-nych w weterynarii. SGGW, Warszawa.
Summary
The objective of the research was to assess and compare contents of selected microelements (zinc, copper and iron) in cow blood serum during the dry period and the period of increasing lactation. Studies were carried out on a farm situated in southern Podlasie. The average milk yield per cow was about 5400 litres.
Cow blood, sampled before feeding (in the morning), was taken from the external jugular vein. Sampling was performed six times, that is every two weeks during the period of drying off (2n, 4t and 6th week), and at one-months intervals during the lactation period (1st, 2nd and 3rd month). Concentrations of microelements examined in blood serum were determined by atomic absorption spectrophotometry method.
Concentration of selected microelements in the cow blood serum depended on their physiological status. The lower and statistically significant copper and iron concentrations were determined in the blood serum of lactating cows. Deficiencies in supplementing cows with copper and zinc in the Podlasie region examined should be supplemented by applying mineral mixtures in cow rations. Their composition and percentage of ingredients should be developed on the basis of contents of these elements in the soil, plants and cow organisms.
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