It was demonstrated in previous reports that several subjects of “Bufala Mediterranea Italiana” showed a variable clot yield between 22 and 30%, despite having the same milk chemical composition, the same diet and the same days open. Till now correlations between genetic variants and milk yield have not been observed in buffalo species, but the possibility that one animal shows similar milk yield values in successive lactations, may be indicative of the utility of selecting for that character. Currently, PKM supplies information on the quantity of mozzarella cheese produced/lactation, but it does not take into account the milk attitude to the cheese-making. Therefore, we thought it worth ascertaining to verify the repeatability of the “milk yield” character and the possibility of classifying one subject in the categories “high” or “low” milk yield. This may avoid monthly controls during the lactation, because, in case of a positive result, the character could be included in the selection programs of the species, whose milk is only used for the cheese-making. During the first year of the trial, 1.5 litres of milk samples from the morning milking were collected monthly from 26 buffaloes. In 10 of them, other milk samples were also collected between 120 and 150 days open for 2 times during the followed year. The buffalo diet was constant throughout the trial (0.92 UFL/Kg DM, 16% CP, 38% NDF, 31% NSC, 0.68% Ca and 0.38% P). Milk clot yield was evaluated by heating the milk at 42°C and adding 5 ml liquid clot (1:10000 title), according to the method described by Intrieri et al. (1986), in each sample. The clot was weighed after 4 hours, stored at 4°C, and weighed again after 24 hours from its constitution, upon whey elimination. Statistical analysis was performed by using ANOVA and the analysis of the correlation coefficients Significant values of the correlation coefficients were observed between the first and second year at 120 and 150 days for milk production (0.809; P< 0.01), milk clot yield at 4 (0.765; P< 0.01) and 24 (0.732; P< 0.05) hours and quantity of clot for each percent point of proteins (0.672; P< 0.05). If the value recorded in the first month is excluded (Table I) the grams of clot obtained from 1 litre of milk increased progressively during lactation (r = 0.534 and r= 0.527 respectively; P< 0.01). Between 121 and 180 day open the values were constant and not statistically different from those registered in other periods; the only variation was represented by a slight lowering registered between 241 and 270 days open. This variation was probably due to the coincidence with the period in which buffaloes were milked once daily and were near to dry themselves. The values in clot weight, both at 4 and 24 hours, at the different days open were always significantly correlated with the average of the total lactation, excluding those at the end of lactation (> 270 days). Higher correlation coefficients were obtained at 115 and 150 days. The mean of these values was highly correlated with the milk clot yield of the total lactation (r= 0.79 and r= 0.93, respectively at 4 and 24 hours; P<0.000). The grams of clot from 1 litre of milk were repeatable in the same buffalo during the two successive years, although the data need to be confirmed by further experiments. The value of the correlation coefficient between the average of the clot weight at 115 and 150 days open and the average of milk clot yield of each buffalo indicates that it is possible to reduce the number of controls for identifying the individual milk clot yield from 9 to 2

Repeatability of milk clot yield and possibility of reducing the number of controls required to identify the individual yield in the buffalo / Zicarelli, Luigi; Potena, A.; Amante, L.; DI PALO, Rossella. - In: VETERINARY RESEARCH COMMUNICATIONS. - ISSN 0165-7380. - STAMPA. - 28:Suppl:1(2004), pp. 245-247. [10.1023/B:VERC.0000045417.99121.9f]

Repeatability of milk clot yield and possibility of reducing the number of controls required to identify the individual yield in the buffalo

ZICARELLI, LUIGI;DI PALO, ROSSELLA
2004

Abstract

It was demonstrated in previous reports that several subjects of “Bufala Mediterranea Italiana” showed a variable clot yield between 22 and 30%, despite having the same milk chemical composition, the same diet and the same days open. Till now correlations between genetic variants and milk yield have not been observed in buffalo species, but the possibility that one animal shows similar milk yield values in successive lactations, may be indicative of the utility of selecting for that character. Currently, PKM supplies information on the quantity of mozzarella cheese produced/lactation, but it does not take into account the milk attitude to the cheese-making. Therefore, we thought it worth ascertaining to verify the repeatability of the “milk yield” character and the possibility of classifying one subject in the categories “high” or “low” milk yield. This may avoid monthly controls during the lactation, because, in case of a positive result, the character could be included in the selection programs of the species, whose milk is only used for the cheese-making. During the first year of the trial, 1.5 litres of milk samples from the morning milking were collected monthly from 26 buffaloes. In 10 of them, other milk samples were also collected between 120 and 150 days open for 2 times during the followed year. The buffalo diet was constant throughout the trial (0.92 UFL/Kg DM, 16% CP, 38% NDF, 31% NSC, 0.68% Ca and 0.38% P). Milk clot yield was evaluated by heating the milk at 42°C and adding 5 ml liquid clot (1:10000 title), according to the method described by Intrieri et al. (1986), in each sample. The clot was weighed after 4 hours, stored at 4°C, and weighed again after 24 hours from its constitution, upon whey elimination. Statistical analysis was performed by using ANOVA and the analysis of the correlation coefficients Significant values of the correlation coefficients were observed between the first and second year at 120 and 150 days for milk production (0.809; P< 0.01), milk clot yield at 4 (0.765; P< 0.01) and 24 (0.732; P< 0.05) hours and quantity of clot for each percent point of proteins (0.672; P< 0.05). If the value recorded in the first month is excluded (Table I) the grams of clot obtained from 1 litre of milk increased progressively during lactation (r = 0.534 and r= 0.527 respectively; P< 0.01). Between 121 and 180 day open the values were constant and not statistically different from those registered in other periods; the only variation was represented by a slight lowering registered between 241 and 270 days open. This variation was probably due to the coincidence with the period in which buffaloes were milked once daily and were near to dry themselves. The values in clot weight, both at 4 and 24 hours, at the different days open were always significantly correlated with the average of the total lactation, excluding those at the end of lactation (> 270 days). Higher correlation coefficients were obtained at 115 and 150 days. The mean of these values was highly correlated with the milk clot yield of the total lactation (r= 0.79 and r= 0.93, respectively at 4 and 24 hours; P<0.000). The grams of clot from 1 litre of milk were repeatable in the same buffalo during the two successive years, although the data need to be confirmed by further experiments. The value of the correlation coefficient between the average of the clot weight at 115 and 150 days open and the average of milk clot yield of each buffalo indicates that it is possible to reduce the number of controls for identifying the individual milk clot yield from 9 to 2
2004
Repeatability of milk clot yield and possibility of reducing the number of controls required to identify the individual yield in the buffalo / Zicarelli, Luigi; Potena, A.; Amante, L.; DI PALO, Rossella. - In: VETERINARY RESEARCH COMMUNICATIONS. - ISSN 0165-7380. - STAMPA. - 28:Suppl:1(2004), pp. 245-247. [10.1023/B:VERC.0000045417.99121.9f]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/201510
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