Influence of parity on concentrations of enzymes, proteins, and minerals in the milk of cows

Influência do número de parições nas concentrações de enzimas, proteínas e minerais no leite de vacas

beef cows; biochemistry; parity; colostrum; milk

vaca de corte; bioquímica; ordem de parição; colostro; leite

COMMUNICATION

Influence of parity on concentrations of enzymes, proteins, and minerals in the milk of cows

Influência do número de parições nas concentrações de enzimas, proteínas e minerais no leite de vacas

T.G. Rocha^I; C. Franciosi^I; R.P. Nociti^II; P.C. Silva^III; A.A.M. Sampaio^III; J.J. Fagliari^III,*

^IAluna de pós-graduação - Faculdade de Ciências Agrárias e Veterinárias - UNESP - Jaboticabal, SP

^IIMédico veterinário autônomo

^IIIFaculdade de Ciências Agrárias e Veterinárias - UNESP - Jaboticabal, SP

Keywords: beef cows, biochemistry, parity, colostrum, milk

RESUMO

Avaliou-se a influência do número de parições nos valores de alguns parâmetros bioquímicos e do perfil eletroforético do soro lácteo de vacas de corte. Trinta e cinco vacas da raça Canchim foram alocadas em cinco grupos: vacas de primeira lactação, segunda lactação, terceira e quarta lactações, quinta lactação e sexta lactação. As amostras de secreção láctea foram coletadas imediatamente após (dia 0) e 1, 2, 7, 15 e 30 dias após o parto. As concentrações de gamaglutamiltranferase (GGT), proteína total, cálcio, fósforo, magnésio e cálcio ionizado foram avaliadas. A separação eletroforética das proteínas foi realizada em matriz de gel de poliacrilamida (SDS-PAGE). A atividade de GGT e as concentrações de imunoglobulina G, cálcio e fósforo não foram influenciadas pelo número de parições. As concentrações de proteína total, cálcio ionizado, magnésio imunoglobulina A, lactoferrina, β - lactoglobulina e α - lactoalbumina, foram influenciadas pelo número de partos das vacas. À exceção dos teores de fósforo e α - lactoalbumina em poucos grupos, a concentração d a s demais características decresceu no decorrer do período de lactação.

Palavras-chave: vaca de corte, bioquímica, ordem de parição, colostro, leite

The composition and physical properties of colostrum vary according to a number of factors such as the age of the animal, number of lactation cycles, breed, diet, vaccination, and diseases (Kume and Tanabe, 1993; Tsioulpas et al., 2007). For instance, it is well established that first lactation heifers produce significantly less colostrum than multiparous cows and that the quality of this colostrum is usually poor (Petrie et al., 1984). Also, dairy cows have more developed mammary glands that often produce a much higher amount of colostrum when compared to beef cows. Colostrum is also the main source of minerals for newborn calves. The concentrations of minerals such as calcium, phosphorus, and magnesium in bovine colostrum are higher at calving and decrease with time (Kume and Tanabe, 1993).

The aim of this study was to evaluate the influence of parity on some parameters of colostrum and milk whey of beef cows in the first 30 days of lactation.

The lacteal secretions of 35 Canchim cows were analyzed. Five groups comprising seven cows each were formed to evaluate whether the number of lactations influenced the content of proteins and the biochemical parameters of colostrum and milk whey. The groups consisted of: seven first lactation cows (Group 1), seven second lactation cows (Group 2), three third and four fourth lactation cows (Group 3), seven fifth lactation cows (Group 4) and seven sixth lactation cows (Group 5). Third and fourth lactation cows were included together in Group 3 because of the small number of animals available for the experiment. The samples of colostrum and milk were taken immediately after calving (day 0) and 1, 2, 7, 15 and 30 days thereafter. All cows were managed under similar conditions prior to and during sample collection. None of the animals used in this study exhibited any health problems during the experimental period. The experimental design was approved by the Ethics Committee on Animal Use at the School of Veterinary Medicine, UNESP at Jaboticabal, under protocol number 009793-08.

Wheys from colostrum and milk were obtained by addition of 5mL of rennet (Coalho Estrella^®, Chr. Hansen Brasil Ind. e Com. LTDA, Valinhos, São Paulo, Brazil) to 100mL of lacteal secretions. After stirring and incubation at 37ºC for 20 minutes, the whey was separated by centrifugation. Whey samples were then frozen and kept at -20ºC until analysis. Gamma-glutamyltransferase (modified Szasz method), total protein (biuret method), calcium (CPC reaction), phosphorus (modified Daly and Ertinghausen method), and magnesium (Labtest reaction) were then determined spectrophotometrically using commercial reagents (Labtest Diagnostica, Lagoa Santa, Minas Gerais, Brazil). Ionized calcium levels were determined by the ion-selective electrode method (9180 Electrolyte

Analyzer, Roche Diagnostics, Mannheim, Germany). Whenever necessary, the samples were diluted in deionized water as follows: gamma-glutamyltransferase: 1:150 (day 0), 1:50 (day 1), 1:20 (days 2 to 30); total protein: 1:3 (day 0; no further dilutions in the subsequent time points); calcium, phosphorus, and magnesium: 1:5 (days 0 to 30); ionized calcium: 1:3 (days 0 to 30).

Electrophoretic protein separation was carried out in polyacrylamide gels using the technique described by Laemmli (1970).

The data were submitted to ANOVA and the differences among groups were analyzed with the Tukey's test. Differences were considered significant at P<0.05 (Zar, 1999).

Even though gamma-glutamyltransferase (GGT) activity levels did not differ between groups, they were higher in colostrum whey of group 1 as compared to group 3 or later lactation cows (Table 1), which is probably due to concentration of this enzyme in a lower volume of colostrum. There was a decrease in GGT activities during the transition from colostrum to mature milk. Zanker et al. (2001) reported a GGT activity of 30,479 IU/L in colostrum whey of primiparous cows two hours after calving and, according to these authors, the activity of this enzyme is very high in colostrum soon after calving and gradually decreases as days go by.

Total protein concentrations were significantly higher in colostral whey of groups 2 and 4 and lower in group 5 (Table 1). Zarcula et al. (2010) reported that breed and parity influenced the chemical composition of first colostrum, and that protein content of whole colostrum was higher in cows from second and third lactation compared to those in fourth lactation, differing from the results of the present study.

Calcium concentrations in whey did not differ between groups and gradually decreased until the thirtieth day of lactation (Table 1). Contrary to the results of this study, Kume and Tanabe (1993) reported a higher concentration of calcium in colostrum of primiparous Holstein cows as compared to multiparous cows of the same breed. Ionized calcium concentration was significantly higher in group 2 and lower in groups 3 and 4 (Table 1). Like total calcium levels, ionized calcium concentrations also gradually decreased until 30 days postpartum. In the present study, ionized calcium levels were higher than those reported by Tsioulpas et al. (2007).

The inorganic phosphorus content levels of colostrum whey did not differ between groups (Table 1). According to Kume and Tanabe (1993), inorganic phosphorus concentrations are higher in colostrum of primiparous Holstein cows as compared to multiparous cows and remain constant after the third lactation. These results differ from the findings of the present study most likely because colostrum whey instead of whole colostrum was analyzed.

The concentrations of calcium and inorganic phosphorus in cow colostrum described in literature are 3-4 times higher than those found in the present study (Tsioulpas et al., 2007). These differences are probably a consequence of the fact that casein binds calcium and inorganic phosphorus and is separated from whey by addition of rennet and centrifugation, which significantly reduces the amount of these two minerals in colostrum whey as compared to whole colostrum.

In addition, Klimes et al. (1986) failed to find a correlation between calcium and phosphorus content and protein concentration in bovine colostrum whey; this is in contrast with the results reported by Gaucheron (2005), who found a significant positive correlation between these parameters in whole milk. These findings lead to the conclusion that the correlation between calcium and inorganic phosphorus and protein fraction of colostrum and milk is due to the interactions between these minerals and casein.

The magnesium content of colostrum whey was higher in group 2 than in the remaining groups and gradually decreased after the onset of lactation (Table 1). Magnesium levels found in group 2 are similar to those reported by Kume and Tanabe (1993). Apparently, the concentration of this mineral is not affected by casein removal.

As in the study of Klimes et al. (1986), the levels of constituents such as calcium, magnesium, and inorganic phosphorus were much higher at the first milking postpartum. Kume and Tanabe (1993) reported that the colostrum concentrations of calcium, phosphorus, and magnesium were higher immediately after calving and decreased rapidly in the subsequent 24h, which is in contrast with the findings of the present study in which the concentration of these elements also decreased, but in a much slower fashion.

Interestingly, immunoglobulin A (IgA) levels in colostrum whey of group 1 were higher as compared to group 2 (Table 2). The highest concentration of this protein was observed on the day of calving and decreased after the onset of lactation in all groups. Muller and Ellinger (1981) reported that first calf heifers produced a lower level of colostral IgA than third or later lactation cows; these findings differ from the results of the present study.

Lactoferrin concentrations in whey from both colostrum and milk were lower in groups 1 and 5 and higher in group 2 (Table 2). The concentrations of this protein also decreased after the onset of lactation in all groups. Tsuji et al. (1990) found no significant differences regarding lactoferrin levels between colostrum of primiparous and multiparous beef cows, which differ from the results of the present. In dairy cows, however, these authors observed a lower lactoferrin content in colostrum of first lactation cows as compared to multiparous cows, which is in agreement with the results of the present study. These authors also reported the presence of significantly higher lactoferrin content in the colostrum produced by dairy cows than in that produced by beef cows.

Heavy chain immunoglobulin G (IgG) concentrations did not differ between groups; they were higher on the day of calving and decreased after the onset of lactation (Table 2). Light chain IgG concentrations exhibited the same trend during the experimental period. Sant'ana (2004) reported intermediate immunoglobulin concentrations in first lactation heifers, lower values in second and third lactation cows, and higher values in fourth or later lactation cows.

Colostral beta-lactoglobulin (β-LG) concentrations were lower in group 1 and 5 and higher in group 2 (Table 2). There was also a difference between groups on the first day after calving, when the highest concentration of this protein was observed in group 1. Differently from the present study, Sant'ana (2004) observed a higher concentration of β-LG in colostrum whey of primiparous cows compared with cows in the fourth or later lactations.

Alpha-lactalbumin (α-LA) concentration in colostrum whey was higher in group 2 and lower in groups 1, 3, and 5 (Table 2). A small decrease in the concentration of this protein was observed in the first thirty days of lactation. Sant'ana (2004) observed the highest concentrations of α-lactalbumin in primiparous cows, which is in contrast with the findings of the present study.

The number of cows used in this study was small and it is likely that grouping these animals as primiparous versus multiparous would have yielded different results; therefore, further research with larger numbers of cows are warranted.

The concentrations of GGT , immunoglobulin G (both heavy and light chains), calcium, and phosphorus were not influenced by parity in Canchim cows. Concentrations of total protein, lactoferrin, β-lactoglobulin, α-lactalbumin, ionized calcium, and magnesium were higher in multiparous cows, whilst immunoglobulin A concentration was higher in primiparous cows.

ACKNOWLEDGEMENTS

The authors thank Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) for the financial support and scholarships.

REFERENCES

GAUCHERON, F. The minerals of milk. Reprod. Nutr. Dev., v.45, p.473-483, 2005.

KLIMES, J.; JAGOS, P.; HOUDA, J. et al. Basic qualitative parameters of cow colostrum and their dependence on season and postpartum time. Acta Vet. Brno, v.55, p.23-29, 1986.

KUME, S.; TANABE, S. Effect of parity on colostral mineral concentrations of Holstein cows and value of colostrum as a mineral source for newborn calves. J. Dairy Sci., v.76, p.1654-1660, 1993.

LAEMMLI, U.K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature, v.227, p.680-685, 1970.

MULLER, L.D.; ELLINGER, D.K. Colostral immunoglobulin concentrations among breeds of dairy cattle. J. Dairy Sci., v.64, p.1727-1730, 1981.

PETRIE, L.; ACRES, S.D.; McCARTNEY, D.H. The yield of colostrum and colostral gammaglobulins in beef cows and the absorption of colostral gammaglobulins by beef calves. Can. Vet. J., v.25, p.273-279, 1984.

SANT'ANA, V.A.C. Proteinograma do leite de vacas: padrões e variabilidade. 2004. 161f. Tese (Doutorado em Medicina Veterinária) - Universidade de São Paulo, São Paulo, 2004.

TSIOULPAS, A.; GRANDISON, A.S.; LEWIS, M.J. Changes in physical properties of bovine milk from the colostrum period to early lactation. J. Dairy Sci., v.90, p.5012-5017, 2007.

TSUJI, S.; HIRATA, Y.; MUKAI, F. et al. Comparison of lactoferrin content in colostrum between different cattle breeds. J. Dairy Sci., v.73, p.125-128, 1990.

ZANKER, I.A.; HAMMON, H.M.; BLUM, J.W. Activities of γ-glutamyltransferase, alkaline phosphatase and aspartate-aminotransferase in colostrum, milk and blood plasma of calves fed first colostrum at 0-2, 6-7, 12-13 and 24-25 h after birth. J. Vet. Med. A, v.48, p.179-185, 2001.

ZAR, J.H. Biostatistical analysis. 4.ed. New Jersey: Prentice Hall, 1999. 663p.

ZARCULA, S.; CERNESCU, H.; MIRCU, C. et al. Influence of breed, parity and food intake on chemical composition of first colostrum in cow. Anim. Sci. Biotech., v.43, p.154-157, 2010.

Recebido em 30 de abril de 2012

Aceito em 20 de agosto de 2013

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corresponding author)

Publication Dates

• Publication in this collection
  17 Mar 2014
• Date of issue
  Feb 2014

History

• Accepted
  20 Aug 2013
• Received
  30 Apr 2012