Open Journal of Veterinary Medicine, 2014, 4, 322-328 Published Online December 2014 in SciRes. http://www.scirp.org/journal/ojvm http://dx.doi.org/10.4236/ojvm.2014.412039 How to cite this paper: d’Paula, J.T., et al. (2014) Blood and Milk Glutamine + Glutamate and Milk Composition in Lactating Holstein Cows in Semi-Arid of Brazil. Open Journal of Veterinary Medicine, 4, 322-328. http://dx.doi.org/10.4236/ojvm.2014.412039 Blood and Milk Glutamine + Glutamate and Milk Composition in Lactating Holstein Cows in Semi-Arid of Brazil Joyci Torres d’Paula 1 , Rafael Leonardo Vargas Martinez 2 , Telga Lucena de Almeida Craveiro Alves 1 , Stephania Katurchi Mendes Mélo 1 , Marianne Kutschenko 3 , Eduardo Terra Nogueira 3 , Helena Emília Cavalcanti da Costa Cordeiro Manso 1 , Hélio Cordeiro Manso Filho 1* 1 Departamento de Zootecnia, Universidade Federal Rural de Pernambuco, Recife, Brazil 2 Associação Pernambucana dos Criadores, Recife, Brazil 3 Ajinomoto do Brasil, São Paulo, Brazil Email: * hmanso@dz.ufrpe.br Received 7 November 2014; revised 3 December 2014; accepted 24 December 2014 Copyright © 2014 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract Our objectives were to measure glutamine (Gln) and glutamate (Glu) concentrations in the milk and blood of lactating Holstein cows, as well as milk composition and somatic cell count (SCC) throughout different stages of lactation. Samples were collected from 21 cows in the 1 st , 2 nd , 3 rd , 5 th and 10 th months of lactation. It analyzed Gln and Glu in the blood and Gln, Glu, lactose, fat, protein and somatic cells in the milk. Also, it measured Gln and Glu in blood from these dairy cows’ calves. Results were analyzed using one-way ANOVA, T-test and Tukey’s test, with a 5% significance level. There was a difference in blood [Gln] in from dairy cows (P < 0.05), with lost concentration ob- served at 2 nd (~0.181 µmol/mL) and 5 th (~0.190 µmol/mL) months of lactation and the highest at 10 th month (~0.276 µmol/mL). Also there was a higher protein content in the 5 th and 10 th months of lactation (~3.61% each) when compared to the other months (P < 0.05). There was no differ- ence in calves’ parameters and in all others parameters from dairy cows. We concluded that the lactation period produced a significant interference in blood [Gln] but not in milk [Gln] which may indicate increase in utilization or decrease in production of this amino acids during lactation in these cows under tropical conditions. Keywords Amino Acid, Lactation, Bovine, Ruminant * Corresponding author.