Arch. Tierz., Dummerstorf 49 (2006) Special Issue, University of Warmia and Mazury in Olsztyn, Faculty of Animal Bioengineering, Poland

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1 Arch. Tierz., Dummerstorf 49 (2006) Special Issue, University of Warmia and Mazury in Olsztyn, Faculty of Animal Bioengineering, Poland STANISŁAW MILEWSKI and WIESŁAW SZCZEPAŃSKI Effects of electromagnetic fields on the meat performance and wool performance of sheep Abstract The effects of pulsed electromagnetic fields (PEMF) on ewes were determined in two experiments. The ewes were exposed to the fields twice daily, for 12 minutes, in a pen covered with flat coils generating a PEMF at a frequency of 33 Hz, with magnetic induction ranging from about 3.5 µt at the floor to about 92 µt on the surface of the coils. Experiment 1 was performed on ewes aged 4 to. The following parameters were analysed: body weight, daily gains, cross-section measurements of the dorsal muscle (musculus longissimus dorsi - m. l. d.), thickness of the fat layer over the loin eye, greasy wool production, staple length, staple thickness and staple strength, as well as hematological and biochemical blood indices and acid-base equilibrium parameters. Experiment 2 was conducted on adult ewes during 70-day lactation, and their wool performance was determined, like in experiment 1. It was found that PEMF had a significant and positive effect on the body weights and daily gains of growing ewes, and on the depth and cross-section area of m. l. d. This could be a consequence of the stabilizing effect of PEMF on metabolic processes, as suggested by lower AST activity, lower concentrations of creatinine and urea, as well as increased oxygen supply to cells confirmed by a lower oxygen saturation percentage (O 2 SAT). No direct correlations were found between exposure to PEMF and wool performance, staple length and wool quality traits. Key Words: sheep, electromagnetic fields, meat performance, wool performance, blood parameters. Introduction External pulsed electromagnetic fields (PEMF) affect the biological functions of the body (BASSET, 1993; KAFKA, 1998, 2000, 2001; MICHAELIS, 1999). The biological response is evoked particularly by pulsed electromagnetic fields whose frequency and induction resemble those of the Earth s magnetic field (KAFKA, 2000; MICHAELIS, 1999). Modulated electromagnetic signals with a wide frequency spectrum are the most effective since they permit selective activation of metabolic processes (KAFKA, 2000, 2001; MICHAELIS, 1999). The application of such fields to farm animals produces desirable results, e.g. in the treatment of joint and tendon injuries in horses (RAMEY, 1999), or mastitis in cows (MURAUEU et al., 1994). NIEDZIÓŁKA et al. (2001) demonstrated a positive effect on PEMF on the egg hatching rate. The studies conducted so far on sheep suggested that their productivity may be stimulated with specific PEMF (MILEWSKI et al. 2001, 2003, 2005; MILEWSKI, 2004). PEMF were found to have no negative effects on ewes, and to positively influence milk yield and quality, the slaughter value of lambs and reproductive performance traits. The aim of the present study was to determine the effects of pulsed electromagnetic fields on the meat performance, wool performance and blood parameters of growing ewes, as well as on the wool performance of adult ewes. Materials and Methods Experiment 1 was performed on growing ewes, and experiment 2 on adult ewes. In experiment 1 the experimental materials comprised 22 F 1 Kamieniecka crossbreeds by Charolaise sires. At four months of age they were divided into two groups, control (I) and experimental (II), identical in terms of body weight. The ewes of group II were

2 220 exposed to pulsed electromagnetic fields (PEMF) twice daily for 150 days, between 8.00 and a.m. and between 4.00 and 6.00 p.m., in a 2 x 4 m pen covered with four openwork flat coils generating PEMF. The time of each exposure was 12 min. A modulated signal with a peripheral frequency of 33 Hz was applied. Magnetic induction B = 0 was applied for 1/2 of the period, an then it was increased linearly to the maximum value, with the frequency increasing gradually from 500 Hz to 2 khz. Signal polarization was changed every minute. The signal-emitting modules were coupled to the coils installed 80 cm above the floor. Mean values of B of the field in the pen were 3.57 µt at the floor and µt on the surface of the coils. Analysis of meat performance included: body weight, cross-section measurements of the dorsal muscle (musculus longissimus dorsi - m. l. d.) - depth, width and surface area, and the thickness of the fat layer over the loin eye. These parameters were determined three times: at the beginning of the experiment, and after 60 and 150 days of exposure to PEMF, i.e. when the ewes were four, six and nine months of age. The measurements of m. l. d. and fat thickness were determined in vivo, behind the last rib, using a SSD-500 Aloka ultrasonograph with a 7.5 MHz linear probe. Analysis of wool performance included: greasy wool production and staple length per year, and staple thickness and staple strength in 9-month old ewes. Wool characteristics were determined by traditional methods: staple thickness with a MP 3 lanameter, staple strength with a DSz 3 dynamometer. Immediately after the completion of the experimental period blood was collected from the jugular vein for analysis of hematological and biochemical indices and acid-base equilibrium parameters. Hematological analyses included: white blood cell count (WBC), red blood cell count (RBC), hematocrit (HCT), hemoglobin (HBG), platelet count (PLT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). All determinations were made by universally accepted methods, using a Vet ABC 18 hematological analyzer (Animal Blood Counter). Biochemical analyses included: glucose, total protein, activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP), and concentrations of creatinine, urea, cholesterol, triacylglycerols, inorganic P, Ca, Mg, Na +, K + and Cl -. They were determined by standard methods, using an EPOLL 200 spectrophotometer. The CORMAY diagnostic kit was used for glucose, and the ALPHA DIAGNOSTICS kits for the other parameters. The ionogram (Na +, K +, Cl - ) was determined by the potentiometric method, using an Easy Lyte PLUS ion-selective analyzer (Medica, USA). The parameters of acid-base equilibrium, i.e. partial pressure of carbon dioxide, (pco 2 ) and partial pressure of oxygen (po 2 ), bicarbonate concentration (HCO 3 - ), base excess (BE), oxygen saturation of hemoglobin (O 2 SAT), concentration of carbon dioxide (ctco 2 ), were determined with a ph and blood gas analyser (Ciba- Corning C-248, Bayer). In experiment 2 the experimental materials comprised 22 Kamieniecka ewes divided into two groups, control (I) and experimental (II), identical in terms of age, body weight and number of suckling lambs. The ewes of group II were exposed to pulsed electromagnetic fields (PEMF) every day during a 70-day lactation period, as described in experiment 1.

3 221 Analysis of wool performance included: greasy wool production and staple length per year, staple thickness and staple strength at 2, 28 and 70 days of lactation. The parameters were determined by the methods used in experiment 1. In both experiments the ewes were fed as recommended by the Institute of Animal Husbandry (ed. RYŚ, 1998). Over the entire experimental period the control and experimental groups received the same diets, i.e. concentrate CJ, haylage composed of grasses and legumes, and meadow hay. The results were analysed statistically in one- and two-factor orthogonal designs, and the significance of differences between groups was verified by the Student s t-test and the Duncan test. Results and discussion The characteristics of the meat and wool performance of growing ewes are given in Table 1. Table 1 Traits of meat performance and wool performance Specification Traits of meat performance: Body weight (kg) at the age of: Daily gains (g) at the age of: M. L. D. USG scanning: - depth (cm) at the age of: - width (cm) at the age of: - surface area (cm 2 ) at the age of: Fat thickness (mm) at the age of: Traits of wool performance: Greasy wool production per year (kg) Staple length per year (cm) Staple thickness (µm) Staple strength (km) A, B - P 0.01; a, b - P 0.05 Group I II x s x s b b b b a a a a It was found that the experimental ewes had a faster growth rate than the control ewes, and at nine months of age the body weights of the former were significantly higher (P 0.05). This was a consequence of differences in daily gains, which between six and

4 222 nine months of age were significantly higher (P 0.05) in the experimental ewes than in the control ones. Over the analysed period changes were also observed in the measurements of m. l. d. Until six months of age all ewes were characterized by similar parameters of m. l. d. Then a faster rate of changes was observed in the ewes of group II, and at nine months of age the depth and surface area of m. l. d. were significantly greater (P 0.05) in this group. These results showed a beneficial effect of PEMF on the meat performance of ewes and correspond to those obtained in experiments on growing lambs between 2 and 70 days of age (MILEWSKI 2004, MILEWSKI et al. 2005), with an identical PEMF exposure program. Greasy wool production and staple length per year, as well as staple thickness and staple strength, were similar in both groups. The exposure to PEMF did not cause significant changes in hematological indices, but such changes were recorded in biochemical indices and acid-base equilibrium parameters (Table 2). Table 2 Hematological and biochemical blood indices and acid-base equilibrium parameters (Hämatologische und biochemische Indikatoren sowie Indikatoren des Säure-Basen-Haushalts des Blutes) Group Specification I II x S x S WBC (10 9 /l) RBC (10 12 /l) HBG (g/l) HCT (l/l) PLT (10 9 /l) MCV (fl) MCH (pg) MCHC (g/l) Glucose (mmol/l) Total protein (g/l) AST (IU/l) ALT (IU/l) ALP (IU/l) Creatinine (µmol/l) Cholesterol (mmol/l) Triglycerides (mmol/l) Urea(mmol/l) Ca (mmol/l) Inorg. P (mmol/l) Mg (mmol/l) Na + (mmol/l) K + (mmol/l) Cl (mmol/l) ph pco 2 (kpa) po 2 (kpa) HCO 3 (mmol/l) BE (mmol/l) O 2 SAT (%) ctco 2 (mmol/l) A, B - P 0.01; a, b - P a A A B 0.89 B B a B a b B B A 0.98 A A b A b In comparison with the control ewes, the experimental ones showed lower AST activity (P 0.05), lower concentrations of creatinine and urea (P 0.01), and lower ph (P 0.05), O 2 SAT and BE (P 0.01), as well as higher concentrations of inorganic P, Mg and Na + (P 0.01).

5 223 It seems that this could result from the stabilizing effect of PEMF of the animal body, as suggested by a comparison of the biochemical blood indices in the ewes of both groups. In group II all parameters except for Na + concentration remained within the physiological range (KULETA et al. 1993, WINNICKA 2002), whereas in group I urea concentration exceeded the upper limit of normal and Na + concentration - the lower limit of normal. The high urea concentration, accompanied by elevated levels of creatinine and AST activity, may indicate that greater strain was put on the kidneys and liver of the control ewes. A similar stabilizing effect of PEMF was observed in the case of suckling ewes (MILEWSKI 2004). One of the effects exerted by PEMF on metabolic activity may be an increase in the degree of oxygen saturation, due to vasodilatation effects (KAFKA 1998, MICHAELIS 1999) and changes in the hemodynamic properties of blood (MICHAELIS 2001, SPODARYK 2001). This is proved by substantially lower oxygen saturation of hemoglobin (O 2 SAT) in the experimental ewes, indicating easier movement of oxygen into cells. Such an influence of PEMF on O 2 SAT was observed in ewes during lactation (MILEWSKI 2004) and during period before mating (MILEWSKI et al. 2005). The characteristics of the wool performance of adult ewes are presented in Table 3. Table 3 Traits of wool performance (Merkmale der Wolleleistung) Group Day of lactation Specification Statistics I II 2nd 28th 70th Interactions Greasy wool production per year (kg) x s Staple length per year (cm) x s Staple thickness (µm) x s Staple strength (km) x Aa 6.59 b 6.16 Bb xx s A, B - P 0.01; a, b - P 0.05 xx - P 0.01 The ewes of both groups were characterized by similar levels of annual greasy wool production and staple length. No significant differences were found in staple thickness and staple strength, either. However, significant changes in wool quality took place during lactation, and concerned primarily staple strength, which decreased gradually. From 2 to 28 days of lactation staple strength reduced by 1.28 km (P 0.05), and at the second stage of lactation, between 28 and 70 days, by 0.43 km and finally the difference between day 2 and day 70 was found to be highly significant. There was an interaction between these factors (P 0.01). During lactation significant changes in staple strength were observed in the experimental group only; the changes recorded in the control group were statistically non-significant. Our study showed that pulsed electromagnetic fields had no direct effects on annual greasy wool production, staple length and wool quality, which might have resulted from the fact that the experimental ewes were exposed to PEMF during a part of the year only. Reduced staple strength during lactation/suckling is quite normal and results from intense pressure put on the ewe s body over this period. Although this effect was more noticeable in the experimental ewes, it should not be associated with exposure to PEMF. Such a

6 224 possibility was excluded in experiment 1. The reason for this phenomenon is a considerably higher yield of milk and milk components in this group of ewes, as demonstrated by MILEWSKI (2004). Conclusions The investigations showed that PEMF had a significant and positive effect on the body weight and daily gain of growing ewes, and on the depth and cross-section area of m. l. d. This could be a consequence of the stabilizing effect of PEMF on metabolic processes, as suggested by lower AST activity, lower concentrations of creatinine and urea, as well as increased oxygen supply to cells confirmed by a lower oxygen saturation percentage (O 2 SAT). No direct correlations were found between exposure to PEMF and wool performance, staple length and wool quality traits. References BASSETT, C. A. L. : Beneficial effects of electromagnetic fields. J. Cell Bio-Chem., 51, 4 (1993), KAFKA, W. A.: Vasodilatatorische Effekte durch speziell geformte elektromagnetische Felder. Emphyspace, 1 (1998), 1-2 KAFKA, W. A.: Extremely low, wide frequency range pulsed electromagnetic fields for therapeutical use. Emphyspace, 2 (2000), 1-20 KAFKA,W. A.: Die physikalisch-physiologische Grundlage des BEMER 3000 Signals. Emphyspace, 2 (2001), 1-48 KULETA Z.; POLAKOWSKA-NOWAK, G., WOSEK, J.; NIERADKA, R.: Wartości wskaźników hematologicznych i biochemicznych zwierząt w stanach zdrowia choroby. ART Olsztyn. (1993) MICHAELIS, H.: Fachinformation BEMER 3000-Therapie. Academy for bioenergetics, 5 (1999), 1-15 MICHAELIS, H.: The (placebo controlled) effect of pulsed (BEMER 3000 typed) electromagnetic fields on human peripheral blood flow characteristics. Emphyspace, 2 (2001), MILEWSKI, S.: Efekty stymulacji owiec pulsującym polem elektromagnetycznym. Rozprawy i monografie UWM Olsztyn, 100 (2004), 1-69 MILEWSKI, S.; SZCZEPAŃSKI, W.; CZARNIAWSKA-ZAJĄC, S.; POGORZELSKI, M.: Wstępne badania jakości mięsa jagniąt wychowywanych w warunkach stosowania stymulacji pulsującym polem elektromagnetycznym. Zesz. Nauk. Prz. Hod., 68 (2003) MILEWSKI, S.; SZCZEPAŃSKI, W.; POGORZELSKI, M.: Efekty stymulacji owiec pulsującym polem elektromagnetycznym w okresie przygotowania do stanówki. Rocz. Nauk. PTZ, 1, 1 (2005) MILEWSKI, S.; SZCZEPAŃSKI, W.; DEPTA, A.; RYCHLIK, A.: Effect of pulsed electromagnetic fields on hematological and biochemical blood indices and milk production in sheep. Electr. J. Polish Agric. Univ., Vet. Med., 4, 2 (2001) htt:// MURAUEU, V. V.; TAMELA, A. A.; FYADOSAVA N. KH.; KARAVENKAU, A. V.; MURAV EV, V. V.; TAMELO A. A.; FEDOSOVA, N. KH.; KOROVENKOV, A.V.:. An investigation into the quality of mammary gland secretions and the biochemical composition of blood during treatment of cows for mastitis by means of electromagnetic wave therapy. Vest. Akad. Agrar. Navuk Belarusi, 2 (1994), NIEDZIÓŁKA, J.; LIS, M.; SZYMONOWICZ, B.: Wpływ dodatkowego pola magnetycznego na przebieg klucia się piskląt kurzych szczepionych in ovo przeciwko chorobie gumboro. Folia Univ. Agric. Stetin., Zootechnica, 225, 43 (2001), RAMEY, D. W.: Magnetic and electromagnetic therapy in horses. Comp. Contin. Educ. Pract. Vet., 21, 6 (1999),

7 225 RYŚ, R (red.).: Normy żywienia bydła i owiec systemem tradycyjnym. Inst. Zoot., wyd. XII, Kraków (1998) SPODARYK, K.: Red blood metabolism and oxygen affinity: effect of the electromagnetic BEMER 3000 field on healthy adults. Emphyspace, 2 (2001), Authors address Dr. habil. STANISŁAW MILEWSKI Prof. Dr. habil. WIESŁAW SZCZEPAŃSKI Departament of Sheep and Goat Breding University of Warmia and Mazury in Olsztyn ul. Oczapowskiego OLSZTYN, POLAND