Table 1.
Dietary centesimal composition and nutritional value.
Fig 1.
Differences in A) milk production, B) mature equivalent milk production, C) milk protein content and D) milk fat content among cows during the first 32 weeks of the lactation preceding that described in the present paper according to their subsequent treatments. NCa = normal Ca (4 cows), LCa = low Ca (5 cows), LCaLD = low Ca and low DCAD (5 cows). Data were analyzed using a generalized linear mixed model with repeated values using PROC GLIMMIX in SAS[35]. Covariance matrix: SP for milk production, mature milk production, and milk protein content and FA for milk fat content. Vertical bars represent standard errors of the mean. Standard errors are shown every 5 weeks for readability.
Fig 2.
Effect of transient variation in dietary Ca content and the DCAD on A) Ca intake and B) dry matter intake between calving and 32 weeks of lactation. NCa = normal Ca (4 cows), LCa = low Ca (5 cows), LCaLD = low Ca and low DCAD (5 cows). Gray background specifies the period during which cows were fed differentiated diets according to the treatments. Data were analyzed using a generalized linear mixed model with repeated values using PROC GLIMMIX in SAS [35]. Covariance matrix: SP for Ca intake and dry matter intake. Vertical bars represent standard errors of the mean. Standard errors are shown every 5 weeks for readability.
Fig 3.
Effect of transient variation in dietary Ca content and the DCAD on A) plasma OC concentration and B) plasma CTX concentration between 3 weeks before calving and 31 weeks of lactation. NCa = normal Ca (4 cows), LCa = low Ca (5 cows), LCaLD = low Ca and low DCAD (5 cows). Gray background specifies the period during which cows were fed differentiated diets according to the treatments. Data were analyzed using a generalized linear mixed model with repeated values using PROC GLIMMIX in SAS [35]. Covariance matrix: FA for plasma OC content and UN for plasma CTX content. Vertical bars represent standard errors of the mean.
Fig 4.
Effect of transient variation in dietary Ca content and the DCAD on A) daily Ca intake, B) fecal losses of Ca, C) apparent digestibility of Ca, D) urinary losses of Ca, E) Ca secretion in milk and F) Ca balance at 3 weeks before and after calving and at 17 weeks after calving. NCa = normal Ca (4 cows), LCa = low Ca (5 cows), LCaLD = low Ca and low DCAD (5 cows). Gray background specifies the period during which cows were fed differentiated diets according to the treatments. Data were analyzed according to a one-way ANOVA using PROC GLM in SAS [35] at each stage of lactation, considering only the fixed effect of treatment. Symbols represent P-values of the treatment effect: ns = not significant, i.e., P > 0.10; T = tendency, i.e., P < 0.10; * = significant, i.e., P < 0.05; ** = significant, i.e., P < 0.01; and *** = significant, i.e., P < 0.001. Vertical bars represent standard errors of the mean.
Fig 5.
Effect of transient variation in dietary Ca content and the DCAD on A) daily milk production, B) milk Ca content, C) milk protein content and D) milk fat content between calving and 32 weeks of lactation. For figure B, color-filled shapes = morning milk Ca content, and white-filled shapes = evening milk Ca content. Treatments: NCa = normal Ca (4 cows), LCa = low Ca (5 cows), LCaLD = low Ca and low DCAD (5 cows). Gray background specifies the period during which cows were fed differentiated diets according to the treatments. Data were analyzed using a generalized linear mixed model with repeated values using PROC GLIMMIX in SAS [35]. Covariance matrix: SP for milk production and morning milk protein content and FA for morning and evening milk Ca contents, evening milk protein content and morning and evening milk fat contents. Vertical bars represent standard errors of the mean. Standard errors are shown every 5 weeks and in the morning for milk production, milk protein and fat contents for readability. The standard error for milk Ca content is shown every 2 weeks in the morning for readability.
Fig 6.
Effect of transient variation in dietary Ca content and the DCAD on the morning milk A) casein content, B) ratio of colloidal Ca to casein content, C) ratio of soluble Ca to total Ca content and D) ratio of Ca to protein content between calving and 32 weeks of lactation. NCa = normal Ca (4 cows), LCa = low Ca (5 cows), LCaLD = low Ca and low DCAD (5 cows). Gray background specifies the period during which cows were fed differentiated diets according to the treatments. Data were analyzed using a generalized linear mixed model with repeated values using PROC GLIMMIX in SAS [35]. Covariance matrix: SP for milk casein content, un for milk ratio of colloidal Ca to casein content and FA for ratios of soluble to total Ca content and Ca to protein content. Vertical bars represent standard errors of the mean. Standard errors are shown for every two measurements for the milk Ca to protein content ratio for readability.