Evaluation of semen characteristics, oxidative stress, and biochemical indices in Arabian horses of different ages during the hot summer season

Document Type : Full paper (Original article)


Theriogenology Department, Faculty of Veterinary Medicine, Benha University, Benha, Egypt


Egypt is anticipated to be potentially influenced by the global climate warming. Therefore, the current study aimed to evaluate the influence of age on the fertility potential of Arabian stallions during summer breeding months. Arabian horses grouped according to their age into three groups, each involved six stallions: young (5-6 years), middle (11-12 years) and old (15-20 years) age groups, were weekly sampled during the months of July-August. Ejaculates were collected using artificial vagina, Missouri model, and examined for pH, volume, concentration, motility, livability and morphological abnormalities. Serum samples were harvested and assessed for testosterone, total antioxidant capacity (TAC), lipid profile, and copper and zinc levels. Semen pH (P<0.005), spermatozoa motility (P=0.08), sperm morphology (P<0.001), tail abnormalities (P<0.001), and sperm count per ejaculate differed noticeably between stallions’ groups. Testosterone (P=0.07) and TAC (P<0.05) concentrations were markedly affected by stallions’ age. Cholesterol correlated negatively with sperm normality, but serum copper and zinc levels correlated positively with semen volume, sperm cell count and spermatozoa livability. These results revealed that the fertility of stallions is age-dependent and is prominently influenced by lipid metabolism and oxidative stress during hot summer breeding season. It is highly advisable to provide animals’ house (along with feed and drinking water) with the evaporative cooling system and allow morning or late afternoon outdoor activity to bypass the summer hot climates and sustain stallions’ fertility.


Abou-Ahmed, MM; El-Belely, MS; Ismail, ST; El-Baghdad, YRM and Hemeida, NA (1993). Influence of age and season on certain biochemical constituents of seminal plasma of Arabian horses. Anim. Reprod. Sci., 32: 237-244.
Asadi, F; Mohri, M; Adibmoradi, M and Pourkabir, M (2006). Serum lipid and lipoprotein parameters of Turkman horses. Vet. Clin. Pathol., 35: 332-334.
Brauch, GH (2002). Climate change, environmental stress and conflict cases of Bangladesh and Egypt. International Conference on Climate Change and Disaster Preparedness, The Hague, 26 June.
Bronson, FH and Heideman, PD (1994). Seasonal regulation of reproduction in mammals. In: Knobil, E and Neill, JD (Eds.), Physiology of reproduction. (2nd Edn.), Vol. 2, New York, NY, Raven Press. PP: 541-584.
Clay, CM; Squires, EL; Amann, RP and Pickett, BW (1987). Influences of season and artificial photoperiod on stallions: testicular size, seminal characteristics and sexual behavior. J. Anim. Sci., 64: 517-525.
Dowsett, KF and Knott, LM (1996). The influence of age and breed on stallion semen. Theriogenology. 46: 397-412.
El Sisy, GA; Abo El-Maaty, AM and Rawash, ZM (2016). Comparative blood and seminal plasma oxidant/antioxidant status of Arab stallions with different ages and their relation to semen quality. Asian Pac. J. Reprod., 5: 428-433.
Gueorguieva, TM and Gueorguiev, IP (1997). Serum cholesterol concentration around parturition and in early lactation in dairy cows. Rev. Med. Vet., 148: 241-244.
Hambleton, PL; Slade, LM; Hamar, DW; Kienholz, EW and Lewis, LD (1980). Dietary fat and exercise conditioning effect on metabolic parameters in the horse. J. Anim. Sci., 51: 1330-1339.
Hansen, PJ (2009). Effects of heat stress on mammalian reproduction. Philos. T. Roy. Soc. B., 364: 3341-3350.
Hanulakova, S; Mamica, O; Machal, L; Křivanek, I; Filipčik, R; Hošek, M and Chladek, G (2012). Physical properties of stallion semen in relation to some qualitative and quantitative characteristics. Acta Univ. Agric. Silvic. Mendel. Brun., 12: 97-101.
Heldmaier, G; Ortmann, S and Elvert, R (2004). Natural hypometabolism during hibernation and daily torpor in mammals. Respir. Physiol. Neurobiol., 141: 317-329.
Inoue, J; Cerbito, WA; Oguri, N; Matsuzawa, T and Sato, K (1993). Serum levels of testosterone and oestrogens in normal and infertile stallions. Int. J. Androl., 16: 155-158.
IPCC (2007). WG1 4th Assessment Report: Climate Change 2007: The Physical Science Basis: Summary for Policymakers. Paris.
Janett, F; Thun, R; Bettschen, S; Burger, D and Hassig, M (2003). Seasonal changes of semen quality and freezability in Franches-Montagnes stallions. Anim. Reprod. Sci., 77: 213-221.
Jasko, DJ (1992). Evaluation of stallion semen. Vet. Clin. North Am. Equine Pract., 8: 129-148.
Juhász, J; Nagy, P; Kulcsár, M and Huszenicza, GY (2000). Methods for semen and endocrinological evaluation of the stallion: a review. Acta Vet. Brno, 69: 247-259.
Kumar, P; Saini, M; Kumar, D; Jan, MH; Swami, DS and Sharma, RK (2016). Quantification of leptin in seminal plasma of buffalo bulls and its correlation with antioxidant status, conventional and computer-assisted sperm analysis (CASA) semen variables. Anim. Reprod. Sci., 166: 122-127.
Kurz, D; Roach, J and Eyring, EJ (1972). Direct determination of serum zinc and copper by atomic absorption spectrophotometry. Biochem. Med., 6: 274-281.
Leme, DP; Papa, FO and Roser, JF (2012). Reproductive characteristics of stallions during the breeding and non-breeding season in a tropical region. Trop. Anim. Health Prod., 44: 1703-1707.
Marcus, GJ and Durnford, R (1985). Simple enzyme-linked immunoassay for testosterone. Steroids. 46: 975-986.
Massányi, P; Trandzik, J; Nad, P; Koreneková, B; Skalická, M; Toman, R; Lukac, N; Halo, M and Strapak, P (2004). Concentration of copper, iron, zinc, cadmium, lead, and nickel in bull and ram semen and
relation to the occurrence of pathological spermatozoa. J. Environ. Sci. Health A Tox Hazard Subst Environ. Eng., 39: 3005-3014.
Mawyer, JD; Gordon, RK; Cavinder, CA; Vogelsang, MM; Sigler, DH; Love, CC; Brinsko, SP; Blanchard, TL and Teague, S (2012). Thermoregulation of the testicle in response to exercise and subsequent effects on semen characteristics of stallions. J. Anim. Sci., 90: 2532-2539.
Mayer Valor, R; Gómez Cárdenas, G and Fernández Gómez, M (1984). Total lipids and cholesterol in blood serum of the Spanish race of andalusian type horses. Arch. Zootec., 33: 43-48.
McBride, JM and Kraemer, WJ (1999). Free radicals, exercise, and antioxidants. J. Strength Cond. Res., 13: 175-183.
McDonnell, SM and Murray, SC (1995). Bachelor and harem stallion behavior and endocrinology. Biol. Reprod. Mono., 1: 577-590.
Moron, MS; Depierre, JW and Mannervik, B (1979). Levels of glutathione, glutathione reductase and glutathione-s-transferase activities in rat lung and liver. Biochim. Biophys. Acta. 582: 67-78.
Nardone, A; Ronchi, B; Lacetera, N; Ranieri, MS and Bernabucci, U (2010). Effects of climate changes on animal production and sustainability of livestock systems. Livest. Sci., 130: 57-69.

Nazifi, S; Saeb, M and Abedi, M (2003). Serum lipid profiles and their correlation with thyroid hormones in clinically healthy Turkoman horses. Comp. Clin. Path., 12: 49-52.

Neto, CR; Monteiro, GA; Delfiol, DJZ;Farras, MC; Dell’aqua Jr, JA; Papa, FO and Alvarenga, MA (2013). The relationships between scrotal surface temperature, age and sperm quality in stallions. Livest. Sci., 157: 358-363.
Prosser, CL and Heath, JE (1991). Temperature. In: Prosser, CL (Ed.), Environmental and metabolic animal physiology. (4th Edn.), New York, John Wiley and Sons, Inc., PP: 109-165.
Setchell, BP; Maddocks, S and Brooks, DE (1994). Anatomy, vasculature, innervation and fluids of the male reproductive tract. In: Knobil, E and Neill, JD (Eds.), Physiology of reproduction. (2nd Edn.), Vol. 1, New York, Raven Press. PP: 771-825.
Sharma, L; Pandey, V; Nigam, R; Saxena, A; Swain, DK and Yadav, B (2016). Association of oxidative status and semen characteristics with seminal plasma proteins of buffalo semen. Iran. J. Vet. Res., 17: 226-230.
SPSS (2007). SPSS for Windows. Version 16.0. Chicago, SPSS Inc.
Vranković, L; Aladrović, J; Beer-Ljubić, B; Zdelar-Tuk, M and Stojević, Z (2015). Seasonal changes in enzyme activities and mineral concentrations in Holstein stallion blood plasma. Vet. Arh., 85: 235-246.
Vu, HV and Acosta, TJ (2014). Catalase and glutathione peroxidase expression in bovine corpus luteum during the estrous. Anim. Reprod., 11: 74-84.
Wong, WY; Flik, G; Groenen, PM; Swinkels, DW; Thomas, CM; Copius-Peereboom, JH; Merkus, HM and Steegers-Theunissen, RP (2001). The impact of calcium, magnesium, zinc, and copper in blood and seminal plasma on semen parameters in men. Reprod. Toxicol. (Elmsford, NY). 15: 131-136.
World Bank (2009). Water and climate change: understanding the risks and making climate-smart investment decisions. Washington, DC: World Bank, 52911.
Young, IS (1999). Measurement of total antioxidant capacity. J. Clin. Pathol., 54: 339.