Effects of organic zinc supplementation on weight gain, incidence and duration of diarrhea in Holstein calves during the weaning phase

• Grant number: 24/06855-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2024
• End date: August 31, 2025
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Production
• Principal Investigator: Márcia Saladini Vieira Salles
• Grantee: Bruna Mikawa Martins
• Host Institution: Instituto de Zootecnia. Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Nova Odessa , SP, Brazil

Abstract

The raising of calves plays a fundamental role in the milk production system, as it represents a long-term investment in replacing the animals that will form the farm's future herd. Failure in raising newborns is mainly related to morbidity and mortality, both caused by diseases such as diarrhea. As a strategy to minimize problems caused by diseases in calves, immunomodulatory alternatives have increasingly been sought so that the animal's body is more resistant and can deal with pathogens to reduce the use of medications such as anti-inflammatories and antibiotics. In this context, the mineral zinc (Zn), as a food supplement used since the beginning of life, can collaborate with the immune system of animals, promoting a better response from the body to diseases, and reducing their occurrence during suckling phase. This study aims to investigate the action of organic zinc as a dietary supplement on the incidence and duration of diarrhea, as well as the performance of Holstein calves during the lactation phase. 48 male Holstein calves will be used, kept in a collective system from 3 to 30 days of age. The animals will be distributed in a randomized block design into two treatments, as follows: C = control (65 mg of organic zinc); ZnS= supplementation of 130 mg/kg dry matter (DM) of organic zinc in the milk replacer. Clinical parameters will be performed daily to diagnose naturally occurring diarrhea and calculate incidence and duration. Calves will be weighed at birth, at 7, 14, and 28 days of life to calculate weight gain. The data will be analyzed using the SAS MIXED procedure, following the model of repeated measures over time (LITTLE et al., 2006). After ANOVA analysis, significance will be declared when P< 0.05. Variables with binomial distribution, such as frequency and occurrence of diseases and stool score, will be analyzed using generalized linear models, using the GENMOD procedure (SAS 9.3 Inst., Inc., Cary, NC). It is expected that animals supplemented with ZnS treatment will have a lower incidence of diarrhea and thus better performance compared to group C.