Association between gestational age and bovine fetal characteristics measured by transcutaneous ultrasound over the right flank of the dairy cow.

Full Abstract

OBJECTIVE: To determine bovine fetal characteristics significantly associated with increasing gestational age as measured via transcutaneous ultrasonography over the right flank. METHODS: The length of gestation at date of pregnancy diagnosis via transcutaneous and transrectal ultrasonography was determined for 224 dairy cattle by estimation from subsequent calving dates. A separate dataset was created for each measurable fetal characteristic (i.e. thoracic diameter, abdominal diameter, umbilical diameter, placentome length and placentome height) and risk factors significantly associated with gestational age at pregnancy diagnosis within each dataset, including the fetal characteristic, were identified. RESULTS: Abdominal diameter was the most frequently observed fetal characteristic and thoracic diameter was the least. Gestational age at pregnancy diagnosis (d) was significantly associated with fetal thoracic diameter (P < 0.01), abdominal diameter (P < 0.01) and umbilical diameter (P = 0.02) when measured via transcutaneous ultrasound. Within each model, sire breed, dam breed, dam age and/or calf sex were also significantly associated with gestational age. Gestational age at pregnancy diagnosis was not significantly associated with either placentome height or length (P > 0.05). CONCLUSION: Fetal thoracic diameter, abdominal diameter and umbilical diameter were found to be significantly associated with gestational age between approximate days 73 to 190 of gestation. Transcutaneous ultrasonography may prove a useful method of estimating gestational age in the absence of accurate breeding records.

Author information

Author/s: Hunnam, J C (JC); Parkinson, T J (TJ); Lopez-Villalobos, N (N); McDougall, S (S);

Affiliation: Whangarei Veterinary Services, Whangarei, New Zealand. j.glossop(-atsign-)johnes.co.nz

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Australian veterinary journal (Aust Vet J), published in Australia. (Language: eng)

Reference: 2009-Sep; vol 87 (issue 9) : pp 379-83

Dates: Created 2009/08/25; Completed 2009/10/29;

PMID: 19703142, status: MEDLINE (last retrieval date: 10/29/2009, IMS Date: )

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