Methods for increasing whole milk solids: effects on performance and health of dairy calves

Author(s)

Amanda Moelemberg Cezar

• Document type: Master's Dissertation
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2023-07-17

Examining board members

Carla Maris Machado Bittar; Marcos Inácio Marcondes; Alexandre Mendonça Pedroso

• Advisor: Carla Maris Machado Bittar

Abstract

Increasing the total solids (TS) content allows an increase in nutrient intake without changing the supplied volume to benefits dairy calveshealth and performance. Many products are used for this purpose, such as solid correctors added to the liquid diet in a predetermined volume. Different approaches for adjusting the solids content by adding these correctors can benefit the producer. Thus, the studys objective was to evaluate the performance, metabolism, and health of Holsteins calves fed whole milk corrected for 15% ST through the use of a commercial solids corrector (24% CP and 4.8% EE), using two approaches: daily reading of milk Brix or fixed amount based on the average milk solids content of the dairy farm. Male Holstein calves (n = 45) properly colostrums were blocked considering the birth weight and date of birth and randomly assigned to three treatments: 1) Control: Whole milk; 2) Fixed: Whole milk was added with a solids corrector, using a fixed dose of 25 g/L; 3) Brix: Whole milk was added with a solids corrector, using the daily brix reading to increase the solids content to 15%. The experimental period was 56 days, during which the animals received a liquid diet (6 L/d) daily and had free access to water and initial concentrate. Weaning was not part of the study but was performed gradually from the 57th day with a reduction of 1 L/d of the liquid diet. Concentrate consumption, rectal temperature, and fecal score were evaluated daily. Weighing, body measurements, and blood samples were taken weekly. Dry matter intake (DMI) via liquid diet was different between the three treatments (P< 0.01), with values of 883.3, 851.3, and 735.5 g DM/d for Brix, Fixed and Control treatments, respectively. Likewise, there was an effect for the DMI of the initial concentrate (P<0.05), but with greater consumption for the Control (383.6 g DM/day), followed by the Fixed (304 g DM/d) and then for the Brix (251.1 g DM/d). However, treatments did not affect total DMI (P>0.05), suggesting a compensation effect between the liquid and solid diets. Average daily gain (ADG) and body measurements such as height at withers, rump width, and thoracic perimeter were not affected by treatments (P>0.05). However, they increased over the weeks (P<0.01). Health parameters such as fecal score, days with a score >2, number of episodes of diarrhea, and days with fever were similar between treatments. However, the hematocrit percentage (P < 0.05) differed between the analyzed treatments. The different liquid diets did not affect the concentrations of Albumin, Total Proteins, Creatinine, Glucose, and BHBA. In this work, the increase of the % ST of the liquid diet was insufficient to improve performance. However, using a fixed dose resulted in a similar correction performance based on the daily Brix reading, suggesting that a fixed dose of the solids corrector could facilitate management on dairy farms. (AU)

• FAPESP's process: 21/04101-2 - Correction of whole milk solids according to two approaches: Performance and health effects of dairy calves
• Grantee: Amanda Moelemberg Cezar
• Support Opportunities: Scholarships in Brazil - Master