Protein nutrition in late pregnancy, maternal protein reserves and lactation performance in dairy cows

Abstract

Empirical evidence suggests that prolonged underfeeding of protein to late-pregnant dry cows can have modest negative carry-over effects on milk volume and/or protein yield during early lactation, and may also cause increased incidence of metabolic diseases associated with fatty liver. However, assessment of requirements is hampered by lack of information on relationships between dietary intake of crude protein (N × 6·25) and metabolizable protein supply during late pregnancy, and by incomplete understanding of the quantitative metabolism of amino acids in maternal and conceptus tissues. Inability of the postparturient cow to consume sufficient protein to meet mammary and extra-mammary amino acid requirements, including a significant demand for hepatic gluconeogenesis, necessitates a substantial, albeit transient, mobilization of tissue protein during the first 2 weeks of lactation. Ultimately, much of this mobilized protein appears to be derived from peripheral tissues, especially skeletal muscle and, to a lesser extent, skin, through suppression of tissue protein synthesis, and possibly increased proteolysis. In the shorter term, soon after calving, it is likely that amino acids required for hepatic glucose synthesis are diverted from high rates of synthesis of splanchnic tissue and export proteins, including serum albumin. The prevailing endocrine milieu of the periparturient cow, including major reductions in plasma levels of insulin and insulin-like growth factor-I, together with insulin resistance in peripheral tissues, must permissively facilitate, if not actively promote, net mobilization of amino acids from these tissues.

Prepartum and postpartum nutritional management to optimize fertility in high-yielding dairy cows in confined TMR systems

“…These hormones promote and respond to, respectively, energy storage in adipose tissue. During the last 3 weeks of pregnancy, nutrient demands by the foetal calf and placenta are at their greatest (Bell et al, 2000). Cows should be able to meet these requirements from the diet, although DMI may be decreased by 10% to 30% compared with intake during the early dry period.…”

“…Loss of muscle mass may begin before calving and before the initiation of fat mobilization (van der Drift et al, 2012). Maintenance of maternal stores of protein is important for long-term health, productivity and reproduction (Bell et al, 2000). Deficiency in metabolizable protein supply may be linked to ketosis (van der Drift et al, 2012;Lean et al, 2013a) and other peripartal diseases (Roche et al, 2013), which in turn may decrease fertility.…”

Perfil sérico proteico de vacas Holandesas no período de transição

“…A proteólise das proteínas para gerar aminoácidos para a gliconeogênese diante do balanço energético negativo é pouco provável (Bell et al, 2000), pois as concentrações de albumina apresentaram variações discretas e não significativas entre o parto e M1. Além disso, os valores de albumina detectados estão contemplados nos intervalos de 2.600,0 a 3.700,0mg/dL estabelecidos para bovinos na literatura (Kaneko et al, 2008).…”

Effects of silage digestibility on intake and body reserves of dry cows and performance in the first part of the next lactation

“…These results are consistent with a transient contribution of labile body protein to milk protein output during the first 3 weeks of lactation. Using data from an earlier study, Bell et al (2000) calculated a nadir Nitrogen balance (approximately 100 g/ day) at day 7 of lactation, and a return to zero balance during the 4th week of lactation. It is interesting to note that the proportionately higher contribution of body protein occurred alongside a measured higher mobilisation of body fat in the HH cows (i.e.…”