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chpizarro@terracombr

INTERNATIONAL SYMPOSIUM THE FUTURE OF THE SHEEP AND GOAT DAIRY SECTORS

    ZARAGOZA, SPAIN, 28-30 OCTOBER 2004

    SEASONAL VARIATION OF GOAT MILK COMPOSITION AND SOMATIC

    CELL COUNT IN SOUTHEASTERN BRAZIL

     1#22 C.H.Pizarro Borges, P.R.C.Cordeiro and S.Bresslau1UCB - Rio de Janeiro - RJ - Brazil and FESO - Teresópolis - RJ - Brazil 2CCA Laticínios - Av. Antônio Mário de Azevedo, 2.143 - Nova Friburgo - RJ 28630-590 - Brazil Abstract

    Consistent information on goat milk composition and its year-round variation is limited in Brazil. In order to study these variations and provide dairy companies with useful information, bulk tank goat milk samples were collected on a weekly basis between August 2000 and December 2003 from 16 goat farms that supplied 2.96 millions liters of goat milk to a dairy company in southeastern Brazil. A total of 2.020 milk samples were analyzed for percentages of fat, protein, lactose, total solids and somatic cell count (SCC). It was found that composition and SCC varied widely according to season of the year and stage of lactation. Fat concentration increased to peak values of 3.79% in August and decreased to 3.07% in March, with mean level of 3.41%. Protein increased to 3.12% in May and decreased to 2.81% in December, with mean level of 2.98%. Lactose increased to 4.61% in August and decreased to 4.22% in February, with mean level of 4.42%. Total solids increased to 12.32% in August and decreased to 11.08% in January, with mean level of 11.67%. 6-16-1SCC increased to 1.24 X 10 ml in April and decreased to 0.75 X 10 ml in September, with median level 6-1of 0.94 X 10 ml.

    Keywords: goat milk, seasonal variation, composition, somatic cell count. #Corresponding author. E-mail: chpizarro@terra.com.br

Introduction

    The Brazilian goat milk business has been growing rapidly for the past few years, especially in the southeastern region. Nowadays the goat milk industry and producers are concerned in marketing a uniform product both in composition and functional properties. Payment policies based on goat milk quality standards have also been a major subject. Determining accurate milk pricing formulas depends on the knowledge of goat milk composition and its year-round variation (Jenot et al., 2000). However, consistent information

    based on goat farms with different management conditions and locations are limited in Brazil. Some research has been done on gross milk composition from small herds on individual farms (Barros & Leitão, 1992; Guimarães, 1993; Bonassi et al., 1997; Ribeiro et al., 1997) but little has been done to investigate the

    seasonal variation of commercial bulk tank goat milk used in industrial milk and cheese plants (Borges et al.,

    1997; Souza et al., 2002).

    The objectives of the current study were to investigate monthly variations in the composition and SCC of bulk tank goat milk in southeastern Brazil and provide consistent information to the goat milk industry to design strategies to reduce variability in dairy products composition and develop accurate milk pricing formulas.

Materials and Methods

    Bulk tank goat milk samples were collected on a weekly basis between August 2000 and December 2003 from 16 goat farms located in the southeastern Brazil (Rio de Janeiro and Minas Gerais States) that supplied 2.96 millions liters to CCA Laticínios, a local dairy goat company. During tanker truck loading, samples of 70 mL of commingled goat milk from six to ten consecutive milkings were collected from the bulk tank of each farm after five minutes of homogenization and were preserved with bronopol until processing. Samples were analyzed at EMBRAPA Milk Quality Laboratory, Juiz de Fora, MG, Brazil, for percentages of fat, protein, lactose, total solids using Bentley 2000 equipment and somatic cell count (SCC) using Bentley Somacount 300 equipment. The SCC, fat and protein values were corrected according to Zeng (1996) since equipments were calibrated with cow milk standards. The goats raised in the 16 farms were purebreds or crossbreds Saanen, French Alpine or Toggenburg dairy goats. Data were analyzed using the general linear model procedure of Statistical Analysis System (SAS) to evaluate changes over time.

Results and Discussion

    A total of 2.020 bulk tank goat milk samples were analyzed between August 2000 and December 2003. The results, sorted by month of the year, are shown in Table 1 and Figures 1, 2, 3 and 4.

    Seasonal Variation of Goat Milk Composition and Somatic Cell Count in Southeastern Brazil C.H.Pizarro Borges , P.R.C.Cordeiro and S.Bresslau

INTERNATIONAL SYMPOSIUM THE FUTURE OF THE SHEEP AND GOAT DAIRY SECTORS

    ZARAGOZA, SPAIN, 28-30 OCTOBER 2004

    Table 1 Percentages of components and somatic cell count (SCC) of 2.020 bulk tank goat milk samples analyzed between August 2000 and December 2003 in southeastern Brazil acording to months of the year. 1 1 112 Months Samples Milk supplied Fat Total Solids SCCProteinLactose6-1(L) (%) (%) (%) (%) (X 10 ml) ab bbaJanuary 210 251.024 3.13 ? 0.372.86 ? 0.23 4.27 ? 0.15 11.08 ? 0.55 0.95 cdbabFebruary 129 191.493 3.27 ? 0.41 2.89 ? 0.21 4.22 ? 0.14 11.22 ? 0.55 0.98 adecbMarch 115 178.861 3.07 ? 0.38 3.02 ? 0.26 4.32 ? 0.11 11.24 ? 0.62 1.08 deedcdApril 150 196.866 3.36 ? 0.40 3.05 ? 0.22 4.38 ? 0.13 11.64 ? 0.62 1.24 fgheMay 128 156.670 3.61 ? 0.46 3.12 ? 0.23 4.52 ? 0.13 12.12 ? 0.63 1.06 ffgefgeJune 111 146.404 3.61 ? 0.48 3.11 ? 0.29 4.44 ? 0.22 11.99 ? 0.75 0.94 fefheJuly 130 150.550 3.63 ? 0.48 3.05 ? 0.25 4.55 ? 0.14 12.05 ? 0.73 0.94 gdeifAugust 165 275.175 3.79 ? 0.32 3.01 ? 0.24 4.61 ? 0.13 12.32 ? 0.61 0.86 fdgeSeptember 236 316.170 3.63 ? 0.46 2.99 ? 0.21 4.48 ? 0.13 12.02 ? 0.60 0.75 ecdedOctober 238 360.359 3.37 ? 0.45 2.94 ? 0.21 4.40 ? 0.16 11.65 ? 0.65 0.80 debfgcNovember 213 378.277 3.29 ? 0.45 2.89 ? 0.22 4.45 ? 0.27 11.50 ? 0.86 0.77 bcaefbDecember 195 357.490 3.19 ? 0.35 2.81 ? 0.19 4.42 ? 0.16 11.28 ? 0.49 0.92

    Total 2.020 2.959.339 3.41 ? 0.42 2.98 ? 0.23 4.42 ? 0.16 11.67 ? 0.64 0.94 1 2 a,b,c,d,e,f,g,h,i Mean (; standard deviation); Median; Column means with common superscripts do not differ (P > 0.05). 4005,00

    350 4,50300

     2504,00 200(%)3,50 150x 1.000 L 1003,00 50 2,500

    123456789101112 123456789101112MonthsMonths FatProteinLactoseMilk supplied

    Figure 1 Monthly variation of the total milk Figure 2 Mean monthly variation in the

    supplied. percentage of fat, protein and lactose.

     1.50012,50

     12,001.300

     11,501.100

     (%)11,00900

     10,50700x 1.000 cells/mL

     10,00500 123456789101112123456789101112 MonthsMonths Total solidsSCC

    Figure 3 Mean monthly variation in the percentage Figure 4 Median monthly variation in the somatic

    of total solids. cell count (SCC).

    The composition and SCC of bulk tank goat milk varied widely according to two main factors: 1) the seasonal reproduction pattern of dairy goat breeds usually raised in southeastern Brazil, with the majority of the does breeding in March-April, freshening in August-September, reaching peak production in October-November and drying off in May-June; and 2) environmental factors such as heat stress during late spring and summer months (November-March). These factors are also mentioned by Barros & Leitão (1992), Guimarães (1993), Bonassi et al. (1997), Borges et al. (1997) and Ribeiro et al. (1997) in Brazil; Brendehaug

    Seasonal Variation of Goat Milk Composition and Somatic Cell Count in Southeastern Brazil C.H.Pizarro Borges , P.R.C.Cordeiro and S.Bresslau

INTERNATIONAL SYMPOSIUM THE FUTURE OF THE SHEEP AND GOAT DAIRY SECTORS

    ZARAGOZA, SPAIN, 28-30 OCTOBER 2004

    & Abrahamsen (1986) in Norway; Espie & Mullan (1990) in Ireland; Zeng & Escobar (1995) and Guo et al.

    (2001) in the United States and Jenot et al. (2000) in France.

    Although off-season breeding practices were adopted on some of the farms, assuring milk shipments throughout the year, the milk supply was seasonal with a peak to trough ratio of 2.6:1 (November:June) (Table 1 and Figure 1). Borges et al. (1997) also measured a ratio of 2:1 (December:June) for bulk-collected goat milk delivered to a commercial cheese company in Nova Friburgo, RJ, Brazil.

    Fat, protein, lactose and total solids showed the same pattern of seasonal variation. Higher values were observed in late autumn and winter months (May-September) with the majority of the does in late or early lactation and lowest values were observed in late spring and summer months (November-March) with the majority of the does in midlactation. Fat concentration increased to peak values of 3.79% in August and decreased to 3.07% in March, remaining under the mean level of 3.41% between October and April (Table 1

    and Figure 2). Protein concentration increased to peak values of 3.12% in May and decreased to 2.81% in December, remaining under the mean level of 2.98% between October and February (Table 1 and Figure 2).

    Lactose concentration increased to peak values of 4.61% in August and decreased to 4.22% in February, remaining under the mean level of 4.42% between October and April (Table 1 and Figure 2). Total solids

    concentration increased to peak values of 12.32% in August and decreased to 11.08% in January, remaining under the mean level of 11.67% between October and April (Table 1 and Figure 3). 6-1SCC increased to peak values of 1.24 X 10 ml in April during the breeding season of the majority of 6-16-1the does and decreased to 0.75 X 10 ml in September, remaining under the median level of 0.94 X 10 ml

    between August and December (Table 1 and Figure 4). These results support the findings of McDougall &

    Voermans (2002) indicating that estrus resulted in an increase in SCC.

Conclusions

    The results indicated that the composition and SCC varied widely during the year according to season and stage of lactation. Due to the consistency of the sample analyzed, the goat milk industry of southeastern Brazil can rest on these results to design strategies to reduce variability in dairy products composition and develop accurate milk pricing formulas.

References

    Barros, G.C. & Leitão, C.H.S., 1992. Influence of mastitis on the physic-chemical features of goat’s milk.

    Pesq. Vet. Bras. 12: 45-48.

    Bonassi, I.A., Martins, D. & Roça, R.O., 1997. Chemical composition and physic-chemical properties of

    goat’s milk in Brazil. Ciênc. Tecnol. Aliment. 17:57-63.

    Borges, C.H.P., Bresslau, S. & Cordeiro, P.R.C., 1997. Características físico-químicas do leite de cabra th recebido na Queijaria Escola de Nova Friburgo, RJ. Proc. 25Brazilian Congress on Veterinary

    Medicine, Gramado, RS, Brazil, pp. 271.

    Brendehaug, J. & Abrahamsen, R. K., 1986. Chemical composition from a herd of Norwegian goats. J. Dairy

    Res. 53: 211-221.

    Espie, W.E. & Mullan, W.M.A., 1990. Compositional aspects of goat’s milk in Northern Ireland.

    Milchwissenschaft 45: 361-362.

    Jenot, F. et al., 2000. Les taux du lait de chèvres et leur variation. L’Eleveur de chèvres 7:12-15.

    Guimarães, M.P.S.L.M., 1993. Avaliação da estabilidade físico-química do leite caprino congelado durante a

    estocagem comercial. MSc (Vet) thesis, Federal University of Minas Gerais, Brazil.

    Guo, M.R., Dixon, P.H., Park, Y.W., Gilmore, J.A. & Kindstedt, P.S., 2001. Seasonal changes in the

    chemical composition of commingled goat milk. J. Dairy Sci. 84(E.Suppl.): E79-E83. McDougall, S. & Voermans, M., 2002. Influence of estrus on somatic cell count in dairy goats. J. Dairy Sci. 85, 378-383. Ribeiro, A.C. et al., 1997. Variation in goat milk composition along of the year in a herd of Brazilian thsouthest. Proc. 34 Brazilian Animal Science Society Meeting, Juiz de Fora, MG, Brazil, pp. 331-333. Souza, G.N., Cordeiro, P.R.C., Borges, C.H.P., Bresslau, S., Bastos, R.R, Brito, M.A.V.P. & Brito, J.R.F., nd2002. Evaluation of milk quality of dairy goat herds in southeast Brazil. Proc 2 Panamerican Congress

    on Milk Quality and Mastitis Control, Ribeirão Preto, SP, Brazil, pp.82.

    Zeng, S. S., 1996. Comparison of goat milk standards with cow milk standards for analyses of somatic cell

    count, fat and protein in goat milk. Small Rumin. Res. 21, 221-225.

    Zeng, S.S. & Escobar, E.N., 1995. Effect of parity and milk production on somatic cell count, standard plate

    count and composition of goat milk. Small Rumin. Res. 17: 269-274.

    Seasonal Variation of Goat Milk Composition and Somatic Cell Count in Southeastern Brazil C.H.Pizarro Borges , P.R.C.Cordeiro and S.Bresslau

    INTERNATIONAL SYMPOSIUM THE FUTURE OF THE SHEEP AND GOAT DAIRY

    SECTORS

    ZARAGOZA, SPAIN, 28-30 OCTOBER 2004

    Seasonal Variation of Goat Milk Composition and Somatic Cell Count in Southeastern Brazil C.H.Pizarro Borges , P.R.C.Cordeiro and S.Bresslau

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