Impact of prenatal and neonatal nutrition on metabolism and future performance in dairy heifers

Abstract

A connection between early stages of life and health and performance in the adult life has been lately demonstrated. In this thesis three studies were conducted in order to evaluate on the one hand rearing strategies that may improve calves performance, and on the other hand strategies that may be implemented in the future to ameliorate fetal development during pregnancy. In the first study, differences in growth, reproductive and health performance were evaluated between calves fed milk replacer (MR) and calves fed whole milk (WM). No differences were found in milk or solid feed intake and growth performance between treatments. But, the reduced insulin to glucose ratio and the decrease in the number of antibiotic treatments in calves fed WM compared with those fed MR suggested an improvement in glucose metabolism, and a potential benefit on calf health when feeding WM. The second study aimed at evaluating shorta and mediumaterm growth performance and glucose metabolism of dairy calves fed 2, 3 or 4 L of MR twice a day. Calves fed 4 L of MR twice daily had greater ADG during the preweaning period, but were unable to compensate the lack of MR during the weaning process resulting in a decreased ADG compared with calves fed 2 L twice daily. Age at first breeding was greater when calves received 2 L twice daily, but no differences were found on age at pregnancy and conception rate. Also, offering 4 L twice daily of MR had transitory negative effects on glucose metabolism, but those disappeared with age. The third study evaluated the effects of Arg supplementation on uterine artery hemodynamics between 40 and 140 days of gestation as it could foster placental vascularization. Uterine blood flow volume (FV) and other hemoadynamics were determined using Doppler ultrasonography. The measurements included heart rate, FV, pulsatility index, and resistance index. Plasma concentrations of amino acids (AAs), nitric oxide, glucose, insulin growth factor, progesterone (P4), growth hormone, and prolactin were analyzed. Contrary to our hypothesis, Arg supplementation did not increase blood flow to the uterus but did change other parameters that could influence placental and fetal growth such as heart rate, maternal concentration of plasma AAs, or P4 synthesis.

Date of Award	16 Oct 2015
Original language	English
Supervisor	Àlex Bach Ariza (Director) & Sergio Calsamiglia Blancafort (Director)