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Category: SMALL RUMINANT

Poster Session II

PSII-4 - Response variables of Nguni goats to water stress: A prelude into their adaptive capacity in the dry ecozone of Eastern Cape, South Africa

Tuesday, July 18, 2023
8:30 AM – 9:30 AM MT
Location: 140 Aztec/110 Galisteo
Abstract:

Background: The recurring drought and limited rainfall patterns occasioned primarily by climate change in sub-Saharan African countries threaten sustainable animal agriculture. The irreversibility of this natural phenomenon calls for an intensive and urgent selection of adaptable breeds that can cope but with minimal compromise on production indices.



Aim: This research aims to assess, under a water-scarcity simulation study, the adaptive capacity of Nguni goats to regulated watering by evaluating some selected physiological response variables.

Methodologies: Eighteen growing Nguni goats (average age: 1 year; BW: 19.25±1.6 kg) were assigned equally to three treatments: W0 without water restriction WR; W70, WR of 70% ad libitum water intake, WI; and W50, WR of 50% ad libitum WI. WR percentages were calculated based on the daily ad libitum WI of the control (W0) group. The experimental trial lasted for 75-d following a 14-day acclimatization to the housing condition. Data on growth performance, rectal temperatures (RcT), respiratory rate (RR), FAMACHA and body condition scores (BCs) were analyzed using the GLM procedure of SAS (2007).



Results: Final weight (FW) was not affected (P >0.05) by the WR levels. W70 and W50 had similar (P >0.05) DMI, ADG, DMI/metabolic weight and ratio of WI to DMI. The RR decreased (P< 0.05) with WR levels. Compared to W0 and W70, W50 had the highest (P >0.05) FAMACHA scores. W0 had the highest (P< 0.05) BCs, and the values obtained decreased with an increase in WR throughout the experimental period. The RcT of the experimental goats were similar (P< 0.05).



Discussion: The similarity in the BW and RcT of the experimental goats, including the similar DMI and ADG values between W70 and W50, implies their efficient water-saving mechanism and adaptive capacity to maintain body nutrients (Akinmoladun et al., 2019). The FAMACHA values are ≤3 and within the permissible range, suggests that iron metabolism was not impaired to induce anaemia (van Wyk and Bath 2002). The similarity in BCs between W70 and W50 indicates that the goats can manage the depletion of body reserve even at W50 WR. However, the RR decreases in an adaptive attempt to prevent further water loss via pulmonary respiration as the water limitation increases.

Conclusion/recommendation: The ability of Nguni goats to maintain body weight under water stress suggests a form of tolerance and adaptive capacity and thus holds promise for future selection.