Liliana Fadul-Pacheco, Michael Liou, Douglas J. Reinemann and Victor E. Cabrera

NMC Annual Meeting January 2021

Relationship Between Cow’s Social Interactions and Milk Performance: An

Exploratory Use of Social Network Analysis

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Introduction

• Social network analysis (SNA) explores complex relational patterns in communities and provides a description of the social relationships structure (Farine and Whitehead, 2015).

• Dairy cows are social animals

• Understanding their relationships or interactions could help improve management practices, performance and welfare.

• Domestic animals can have positive or negative social interactions (Rault, 2012).

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Introduction• Automatic milking systems (AMS)

environment provides a measure of social interaction in real-time, when cows go through a sort gate when moving from resting to feeding or milking areas.

• These time series data can be used to assess cows’ interactions.

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Objective• Perform an exploratory analysis using SNA to identify potential social relationships

between cows.

• Assess if there was an impact on milk production when the relationships among them is broken.

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Materials and Methods• Data from a commercial dairy farm during a 12-month period was used

• Each pen was fitted with a pre-selection sorting gate

4 pens with 1 DeLaval AMS/pen.

241 ± 36 milking cows

~60 cows/AMS

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Materials and Methods• Cow traffic and milk performance data were made available through the Dairy Brain

project at the University of Wisconsin (Cabrera et al., 2020).

Data on cow traffic:

• provided the time that each cow passes through the sorting gate.

Milk performance data:

• milk yield

• milking time

• lactation number

• days in milk

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Materials and Methods• To consider cow social relationship or affinities: affinity scores were calculated

depending on when cows passed through the sorting gate.

• All scores were normalized by the total time each pair of cows spent together in the pen.

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Wood’s lactation curve model Paired t-test analysis

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Materials and Methods

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Results

Example of the network representation of the social network of pen 1

Results

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Results

Without social affinity:

• Day-to-day variability in milk production in all pens increased by 3.5 times.

• Milk production tended to decrease

• Pen 3 had significant lower milk production: 0.66 kg/d per cow, P-value = 0.03

Results

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Results• Our results suggest that cows separated from

their best friend may produce less milk than cows who are paired with a best friend.

• We hypothesize that moving pairs of best friend cows into new pens could reduce daily variation and loss in milk production.

Results

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Conclusions• A better understanding of cows’ social relationship

structure could be beneficial to improve milk performance and cow welfare.

• Our results suggest that social interactions can impact milk production and likely welfare, even thought this was an exploratory study.

• More studies that promote understanding on social affinities among cows are needed.

Results

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Acknowledgments

This study was supported by the Food and Agriculture Cyberinformatics and Tools grant no. 2019-68017-29935/project accession no. 1019780 from the USDA National Institute of Food and Agriculture.