Evolution of chemical composition, somatic cell count and renneting properties of the milk of Massese ewes

Abstract

The experiment was carried out on 52 lactations of 37 multiparous Massese ewes. Because of the mating practice of the breed, three types of lactation were detected: Type 1, a short lactation initiated in autumn; Type 2, a short lactation initiated in spring, following the Type 1 lactation; Type 3, a long lactation initiated in autumn. Milk yield was recorded weekly, starting not before the eighth day from lambing. On a total 984 milk samples, contents of fat, protein, casein and lactose, SCC, pH and clotting parameters (R, K20 and A30) were determined. Data were analysed by a mixed model including lactation order, lactation type, DIM, and individual lactation as random effects. Protein and casein content increased from the second to ®fth lactation; the highest fat content was detected in the sixth lactation and over; milk of fourth lactation had higher SCC and worse renneting properties than that of second lactation. The pattern of evolution of parameters within the three types of lactation showed that the increase of nutrients with DIM was particularly noticeable for fat content in the Type 2 lactation (spring/short) which exhibited, at an average of 94 DIM, 1.5 percentage units above the other two types. Evolution of lactodynamographic parameters indicates that generally there was a substantial improvement in cheese-making suitability during the ®rst 2±3 months postpartum, and a worsening thereafter. The Type 2 lactation yielded milk with better renneting properties, particularly with respect to milk obtained during the same season from ewes that had an autumn delivery. This suggested that the newly started milk from the spring lactation could have a corrective effect on the total amount of bulk milk produced, a possible advantage for the Massese breed, which is characterised by a particularly pronounced deseasonalisation of lambings. #

Effect of the stage of lactation on milk composition, its properties and the quality of rennet curdling in East Friesian ewes

“…The CN content, which markedly influences the RCT of milk (Gajdůšek and Jelínek, 1992), increased during lactation from 3.35% to 4.94%. A similar trend and comparable CN contents were reported by Jelínek et al (1990) and Pugliese et al (2000). DMY gradually decreased depending on the stage of lactation, which is in line with the results published by Hassan (1995) and Ochoa-Cordero et al (2002).…”

“…The effect of the somatic cell count and the stage of lactation on the plasmin activity and cheese-making properties of ewe milk was studied by Albenzio et al (2004). The evolution of the pH and renneting properties of milk in Massese ewes during lactation was examined by Pugliese et al (2000). The correlations between the components of sheep milk and its rennetability in the crossbreds of Tsigai and East Friesian breeds were investigated by Gajdůšek and Jelínek (1992).…”

Influência do fotoperíodo no consumo alimentar, produção e composição do leite de ovelhas Bergamácia

“…Uma característica importante foi o elevado coeficiente de variação para a produção de leite, e o baixo coeficiente para as porcentagens de gordura, proteína, lactose e sólidos totais, o que foi igualmente observado por Knight et al (1993) e Pugliese et al (2000).…”

“…Como na semana seguinte a contagem voltou aos níveis normais, é possível que o aumento não tenha sido causado por uma mastite subclínica e, sim, por uma situação de estresse que pode, momentaneamente, elevar o número de células somáticas (Figura 1). A saúde da ovelha e, em particular, a da glândula mamária, influencia na quantidade e na qualidade do leite produzido (Bencini & Pulina, 1997;Pugliese et al, 2000). Comparando-se a contagem dessas células com Fuente et al (1997) e Cavani et al (1991, observa-se que a contagem de células somáticas permaneceu baixa neste trabalho, o que permite afirmar que problemas como a mastite subclínica não afetaram os resultados relacionados com a produção e a qualidade do leite.…”

“…Mesmo em países cuja produção de leite é uma tradição de muitos anos, há uma deficiência de novas tecnologias e trabalhos científicos ligados à produção de leite ovino. Entretanto, é de conhecimento geral que o leite apresenta características que permitem transformá-lo em produtos de elevado valor comercial, como queijos e iogurtes (Bencini & Pulina, 1997;Pugliese et al, 2000).…”