Agriculture (May 2022)
Interactions between Social Hierarchy and Some Udder Morphometric Traits upon Colostrum and Milk Physicochemical Characteristics in Crossbred Dairy Goats
Abstract
The possible relationship between udder morphometric variables (UMVs), chemical quality (CHQ) of both colostrum (CA), and milk (MK), as affected by goat’s social rank (SR) (i.e., low-LSR, or high-HSR), was assessed. In late June, goats (Alpine–Saanen–Nubian x Criollo; n = 38; 25° N) were estrus-synchronized and subjected to a fixed-time artificial insemination protocol. Thereafter, in October, while a behavioral study was performed in confirmed-pregnant goats to define the SR classes (n = 15), live weight (LW), body condition (BCS), and serum glucose (GLUC) were registered on the last day of the behavioral study. The expected kidding date was 25 November. Both the UMVs (i.e., seven dates) and the CHQ (i.e., either one for CA and three times for MK) were collected across time (T). The UMVs involved udder perimeter (UDPER, cm), udder diameter (UDDIA, cm), left-teat (LTPER, cm) and right-teat perimeter (RTPER, cm), left-teat (LTLT, cm) and right-teat length (RTLT, cm), left-teat diameter (LTDIA, cm) and right-teat diameter (RTDIA, cm), and medium suspensory ligament (MSL, cm). The registered CHQ variables for both CA and MK were fat (FAT), protein (PRO), lactose (LAC), nonfat solids (NFS), freezing point (FP), and total solids (TS). The possible effect of SR, T, and the SR × T interaction upon the described response variables was tested. While LW favored the HSR goats (54.6 vs. 48.2 ± 1.7 kg; p p > 0.05) between SR. An SR × T interaction affected (p p p p p FAT, > PRO, and > NFS) during early lactation. Therefore, both social rank (i.e., HSR goats), as well as the temporal transition stage from the last third of pregnancy to the first phase of lactation (i.e., time), operated as important modulators upon both udder architecture and milk quality in crossbred dairy goats under a dry-semiarid production system.
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