Date of Award

2024

Document Type

Master Thesis

Degree Name

Masters of Science (Research)

Department

BIOLOGICAL SCIENCES

First Advisor

Dr. Craig Murphy

Second Advisor

Dr. Nóirín McHugh

Abstract

Efficiency and profitability in the beef industry are driven by cattle live-weight, therefore, to optimise live-weight data it is essential to maintain consistency across data collection methods. Data for this thesis was collected from 97,780 Irish suckler herds across the years 2019 to 2022, inclusive, with a total of 1,311,870 calf and dam live-weight records available. Live-weight data originated from five different sources including: professionally-recorded, producer recorded using either owned, borrowed or hired weighing scales, or from an unknown recording source. The objectives of this thesis were to: i) identify anomalies within cattle live-weight data for both calf and dam, using a novel approach (Chapter 2), and to ii) determine the impact of cattle live- weight data sources on the estimation of genetic (co)variances for both calf and dam live-weight (Chapter 3). Results from this thesis showed that, across a variety of different producer live-weight sources, calculating a Mahalanobis distance estimate for each herd, based on the distance from the professionally-recorded data, can aid in the detection of anomaly data within individual herds. Additionally, the herd characteristics associated with individual herd Mahalanobis distance estimates included: herd size, the proportion of dams born within the herd of weighing, calving season, geographical location and the month of live-weight recording. The direct heritability estimates for calf and dam live-weight ranged from 0.20 to 0.34 and 0.46 to 0.52, respectively. The maternal heritability for calf live-weight ranged from 0.04 to 0.08. Across live-weight sources the genetic correlation between calf live-weight measurements and between dam live-weight measurements ranged from 0.37 to 0.96 and 0.22 to 0.90, respectively. Results from this thesis suggest that the use of a novel editing technique can be applied to a wide range of traits and provides an insight into the influence of data source on data quality control in national genetic evaluations for 2 live-weight. Methodologies established in Chapter 2 and 3 potentially will help to form new editing criteria for a range of other continuously recorded data.

Access Level

info:eu-repo/semantics/openAccess

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