1Faculty of Animal Science, Universitas Jenderal Soedirman, Dr. Soeparno Street No. 60, Banyumas53122, Indonesia
2Faculty of Medicine, Nursing and Health Sciences, Monash University, Australia
*Corresponding Author: Apsari Kumalajati, Faculty of Animal Science, Universitas Jenderal Soedirman, Dr. Soeparno Street No. 60, Banyumas53122, Indonesia. Email: apsarikumalajati7@gmail.com
This study aimed to determine whether ketosis during early lactation correlates with low reproductive efficiency in Friesian Holstein-fitted heifers on tropical dairy farms. An internationally acclaimed case, a group of 38 heifers aged 24-36 months from a dairy farm in a government farm in Banyumas, Central Java, Indonesia, was prospectively followed.
On day 7-30 postpartum, the BHBA levels were measured using a validated portable ketone meter operating on an electrochemical enzymatic principle and the animals were grouped into a standard (1.2 mmol/300 ml), subclinical ketosis (1.2-2.9 mmol/300 ml) and a clinical ketosis (3.0 mmol/300 ml) based on the results. The outcomes measured in reproduction were conception rate (CR), services/conception (SC) and days to conception (DC), obtained from records of insemination and pregnancy.
Subclinical and clinical ketosis prevalences were 36.8% and 15.8%, giving a total ketosis prevalence of 52.6%. Pregnancy rate declined with increasing ketosis severity (77.8% in normal, 35.7% in subclinical, 16.7% in clinical) and heifers with normal BHBA showed markedly better reproductive performance (SC 1.5±0.5; DC 95±12 days) than ketotic animals (clinical: SC 3.4±0.9; DC 163±21 days; p<0.01). These findings indicate that elevated BHBA in early lactation is strongly associated with impaired fertility in replacement heifers, supporting the need for regular BHBA monitoring and optimized nutrition to reduce ketosis-related reproductive losses.
Breeding interval, Dairy replacement cattle, Fertility outcomes, Metabolic status, β-hydroxybutyrate
