Relationships between stage of lactation and pregnancy and blood composition in a herd of dairy cows and the influences of seasonal changes in management on these relationships

Abstract

Blood samples, taken on 6 occasions during 1 year from 172 cows resident in a dairy herd, were analysed for packed cell volume, blood glucose, haemoglobin (Hb), serum albumin, urea N, total protein, Ca, inorganic phosphate, Mg, Na and K. The data were analysed statistically, firstly with respect to date of sampling, stage of pregnancy or lactation and the interaction between stage of pregnancy or lactation and date of sampling, and secondly with milk yield as an additional factor for the data for lactating cows.Concentrations of all constituents except inorganic phosphate and K varied significantly (P < 0-001) with stage of lactation and/or pregnancy. The most significant changes in concentrations were confined to the periods up to 3 months either side of calving. The greatest changes in concentration during these periods occurred for Mg which rose during late pregnancy and for albumin which fell at or near calving. Albumin, urea and glucose were all, on average, lowest in concentration during the first month of lactation; globulin concentrations showed the reverse trend. Haemoglobin concentrations decreased during late pregnancy and early lactation and were lowest in the period 30-120 d post partum. Calcium concentrations decreased during late pregnancy and rose during early lactation. Sodium concentrations rose during late pregnancy. Interactions between dates of sampling and stages of lactation or pregnancy were significant (P < 0-001) for all constituents, and most marked for glucose, urea, albumin, Hb, Ca and Na.Haemoglobin and K concentrations fell and Mg concentrations rose with increasing milk yield, but the proportions of the total variance accounted for by differences in milk yield were small in relation to those accounted for by stage of lactation. These findings are of significance in relation to the selection of animals for sampling in the Compton Metabolic Profile Test.

Influence of pregnancy on some erythrocyte biochemical profiles in the rabbits

“…The significant increase in the level of intracellular Na + in the pregnant group (P < 0.001) is comparable to the uniformly observed hypernatraemia during late pregnancy (Kaiser and Cummings, 1958;Rowlands et al, 1975;Kleinman and Lorenz, 1989). This late pregnancy-induced hypernatraem ia maybe as a result of the particularly high aldosterone production, which promotes K + excretion and Na + reabsorption in the renal tubule, during pregnancy (Rowlands et al, 1975).…”

Effects of milking frequency on feed intake, body weight and haemato-biochemical changes in crossbred cows

“…Cows milked three times daily had a 6% lower plasma glucose concentration compared with cows milked two times daily (Andersen et al 2004). Albumin, glucose and Hb values decreased in early lactation with increasing the milk yield while calcium and globulin showed the reverse trend (Rowlands et al 1975). In the present study, decrease in Hb was found as reported by earlier workers.…”

Parâmetros sangüíneos e urinários, no pré e pós parto, de búfalas criadas em sistema exclusivo de pastejo

“…3). Esses achados corroboram com os de Rowlands et al (1975), Quayam et al (1990) e Fagliari et al (1998, que encontraram em vacas bovinas e bubalinas uma diminuição não significativa na PPT nas ultimas semanas de gestação. Isso segundo Mulei (1991) é causado principalmente pela transferência de imunoglobulinas do plasma para o colostro.…”

“…Estes achados são similares os verificados por Samak et al (1981), que também encontraram uma diminuição significativa do hematócrito no pós-parto, principalmente no início e meio da lactação de vacas bovinas. Para Rowlands et al (1975) e Jones et al (1982), a produção de leite no pós-parto seria o fator responsável pela diminuição do hematócrito. Porém, Dirksen et al (1993), afirmam que os fatores nutricionais, como a deficiência de proteínas e minerais (ferro, cobre e cobalto) são as principais fatores responsáveis pela diminuição do hematócrito em vacas bovinas em lactação no pós-parto.…”