REGULAR ARTICLES Ergonomic study of donkeys administered with Pycnogenol® and subjected to packing during the hot-dry season in Northern Nigeria Folashade Helen Olaifa 1 & Joseph Olusegun Ayo 2 & Tangang Aluwong 2 & Peter Ibrahim Rekwot 3 & Friday Ocheja Zakari 2 Received: 29 November 2017 /Accepted: 28 August 2018 # Springer Nature B.V. 2018 Abstract The aim of the study was to determine some ergonomic parameters of donkeys administered with Pycnogenol® (PYC) and subjected to packing during the hot-dry season in northern Nigeria. Fifteen donkeys served as experimental subjects. Group 1 (n = 5) donkeys were subjected to trekking only (control), group 2 (n = 5) donkeys were subjected to packing (P-PYC), and group 3(n = 5) were administered with PYC (10 mg/kg) and subjected to packing (P+PYC). Each group covered a distance of 10 km. Some ergonomic parameters were evaluated. The duration of work in control, P-PYC, and P+PYC donkeys were 170.0 ± 10 min (2.8 h), 126.6 ± 6.7 min (2.1 h), and 112.0 ± 3.9 min (1.9 h), respectively. The energy expenditure obtained for P-PYC group (88.3 ± 9.8 KJ/s) was significantly higher than the values of 28.3 ± 3.7 KJ/s and 73.5 ± 9.9 KJ/s obtained in control and P+PYC groups, respectively. The output was significantly higher in P+PYC group with the value of 5263.2 ± 135 m/h. In conclusion, packing the donkeys during the hot-dry season was stressful; however, PYC may have served as a potent antifatigue agent to reduce the stress. Keywords Ergonomic evaluation . Heart rate . Donkey . Hot-dry season Introduction Donkeys are used mostly for load carrying (packing); loads which include firewood, water, sand, and farm produce over very long distances daily (Minka and Ayo 2007; Nininahazwe et al. 2017) in Nigeria. They are also used for draught purpose and for fetching water from deep wells in Ethiopia (Amante et al. 2014). Thus, working donkeys are at risk of developing multiple, acute, and chronic health problems. The ability to recognize these health problems early in donkeys is important for their welfare (Regan et al. 2016). Equidae is an optimal in vivo model for studying several responses to exercise-induced stress due to their natural apti- tude for exertive performance (Thu et al. 2017). Packing in donkeys is a form of voluntary aerobic muscular exercise (Olaifa et al. 2015), which is carried out in a constant manner (endurance) and can be exhausting (Finisterer 2012). A num- ber of conditions, including exercise, could lead to decreased antioxidant defence, oxidative stress and oxidative damage. Reactive oxygen compounds, initially considered as the only damaging agents in living organisms, have been found to also play positive roles (Roy et al. 2017). However, imbalance between generation and elimination of reactive oxygen com- pounds in favour of generation leads to oxidative stress (Lushchak 2014). Packing of donkeys may cause oxidative stress but it has not been reported if this oxidative stress leads to muscle fatigue or not. This intensive exercise may reflect muscle fatigue, and may eventually cause muscle damage (Finisterer 2012), a common occurrence which can lead to severe complications such as lameness. Therefore, ameliora- tion of muscle fatigue is necessary in order to improve the performance of donkeys used for packing. Nigeria is located in the tropics. Its seasons are determined by rainfall with rainy and dry seasons being the major seasons. It is hot and wet throughout the year particularly in the south- east, but in the west and north, a distinct dry season is ob- served (Oguntunde et al. 2016). Temperature and relative hu- midity remain fairly constant throughout the year in the south, * Folashade Helen Olaifa folashadeakanmu@yahoo.com 1 Department of Veterinary Physiology and Biochemistry, University of Ilorin, Ilorin, Nigeria 2 Department of Veterinary Physiology, Ahmadu Bello University, Zaria, Nigeria 3 National Animal Production and Research Institute, Ahmadu Bello University, Shika, Nigeria Tropical Animal Health and Production https://doi.org/10.1007/s11250-018-1702-8