Determination of colostrum quality using Brix refractometer in sheep

Area of Science:

• Animal Science
• Veterinary Medicine
• Reproductive Biology

Background:

• Colostrum quality is critical for neonatal lamb survival and immunity.
• Accurate and rapid assessment of colostrum's immunoglobulin G (IgG) content is essential for sheep farming.
• Brix refractometry offers a potential field method for colostrum quality evaluation.

Purpose of the Study:

• To evaluate the efficacy of optical and digital Brix refractometers in determining ewe colostrum quality.
• To correlate Brix values with colostral IgG concentrations measured by radial immunodiffusion (RID).
• To establish optimal Brix thresholds for defining good quality ewe colostrum.

Main Methods:

• Colostrum samples (15 mL) were collected from 100 Merino X Kivircik crossbred ewes within 8 hours postpartum.
• Colostral IgG levels were measured using radial immunodiffusion (RID).
• Optical and digital Brix refractometer readings were taken and compared with IgG levels and each other.

Main Results:

• Mean colostral IgG was 156.68 ± 7.23 g L-1; mean Brix values were 27.43 ± 0.53% (optical) and 27.69 ± 0.60% (digital).
• Ewes with twin lambs produced significantly higher quality colostrum than those with single lambs; parity had no effect.
• Brix values showed strong positive correlations with IgG levels (r = 0.70 optical, r = 0.64 digital) and between refractometer types (r = 0.98).

Conclusions:

• Brix refractometers are valuable, reliable tools for assessing ewe colostrum quality in a practical setting.
• An optimal Brix threshold of 22% is recommended for identifying good quality ewe colostrum, with 23% for higher IgG levels (80 g L-1).
• This method facilitates rapid, on-farm evaluation of colostrum, aiding in ensuring adequate passive immunity transfer to newborn lambs.