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Simple Summary: This study was conducted to determine the effects of the incremental temperature humidity index (THI) on oxidant and antioxidant plasma markers in mid-lactating dairy cows. Results showed a significant increase in oxidative markers and a significant decrease in antioxidant defence; this balance results in oxidative stress. Heat stress significantly modulated fat milk content, blood cell number, and plasma metabolite concentration. Animal health is affected during heat stress as a result of impaired immune responses, increased production of reactive oxygen species, and/or a deficiency of antioxidants. This leads to an imbalance between oxidants and antioxidants and results in oxidative stress. Heat stress is usually measured in dairy cattle via the temperature-humidity index (THI). In the present study, we aimed at assessing the influence of incremental THI on the balance between oxidative markers and the antioxidant defence system in the plasma of Modicana cows. Twenty-four multiparous, mid-lactating dairy cows were divided into two groups on the basis of different levels of mean THI reached in the period of the previous week up until the day of blood and milk sampling (April THI1:55, May THI2:68, June THI3:71, July THI4:80). The blood samples were collected to measure reactive oxygen metabolites (ROM) and advanced oxidation protein products (AOPP) on the one hand, and antioxidant defense markers (ferric reducing ability of plasma (FRAP), paraoxonase (PON), plasma thiol groups (SHp)), as well as lipid-soluble antioxidant pro-vitamin (β-carotene) and vitamins (tocopherol and retinol) on the other hand. Milk characteristics, haematological values, and plasma biochemical metabolites were also evaluated. Results showed a significant increase in ROM (p < 0.05) and a significant decrease in PON (p < 0.05), AOPP (p < 0.05), and β-carotene (p < 0.001). Incremental THI significantly decreased levels of milk fat content, red and white blood cells, plasma glucose, and non-esterified fatty acids, while significantly increasing monocytes and the concentrations of β-hydroxybutyrate and creatinine, but not fructosamine. The results of the study show that heat stress significantly affects reactive oxygen species production and antioxidant parameters. Carotenoid supplementation should be considered to alleviate the impact of these effects. [ABSTRACT FROM AUTHOR]

Previous to this study, there is no data relating to the reproductive physiology of the Cirneco dell'Etna breed. The birth date of 141 bitches and 104 sires registered at the National Agency of the Italian Kennel Club (ENCI) from all Sicilian breeders, and data related their fertile matings, which produced 266 whelps over a 14-year period, (2009–2022) were collected. Total whelping produced 1069 pups. The mean bitch age at first whelping was 39.13 ± 21.7 months and the mean litter size was 3.84 ± 2.08. The birth period of the bitches and sires was significantly influenced by the month of the year (p < 0.01), as was the distribution of the first (p < 0.05) and subsequent whelping periods (p < 0.01). Whelping distributions show a significant difference between the highest peak in April (which roughly corresponds to a period of heat in February) and in July (which roughly corresponds to a period of heat in May) and the lowest peak in March. No influence of month on litter size and sex ratio was found. Available data suggests that some ancient breeds such as the Cirneco dell'Etna may show seasonal patterns as a vestige of the stricter seasonality of its closest relative the wolf. [ABSTRACT FROM AUTHOR]

Animal health is affected during heat stress as a result of impaired immune responses, increased production of reactive oxygen species, and/or a deficiency of antioxidants. This leads to an imbalance between oxidants and antioxidants and results in oxidative stress. Heat stress is usually measured in dairy cattle via the temperature-humidity index (THI). In the present study, we aimed at assessing the influence of incremental THI on the balance between oxidative markers and the antioxidant defence system in the plasma of Modicana cows. Twenty-four multiparous, mid-lactating dairy cows were divided into two groups on the basis of different levels of mean THI reached in the period of the previous week up until the day of blood and milk sampling (April THI 1 :55, May THI 2 :68, June THI 3 :71, July THI 4 :80). The blood samples were collected to measure reactive oxygen metabolites (ROM) and antioxidant defense markers (ferric reducing ability of plasma (FRAP), paraoxonase (PON), advanced oxidation protein products (AOPP), plasma thiol groups (SHp), as well as lipid-soluble antioxidant pro-vitamin (β-carotene) and vitamins (tocopherol and retinol). Milk characteristics, haematological values, and plasma biochemical metabolites were also evaluated. Results showed a significant increase in ROM ( p < 0.05) and a significant decrease in PON ( p < 0.05), AOPP ( p < 0.05), and β-carotene ( p < 0.001). Incremental THI significantly decreased levels of milk fat content, red and white blood cells, plasma glucose, and non-esterified fatty acids, while significantly increasing monocytes and the concentrations of β-hydroxybutyrate and creatinine, but not fructosamine. The results of the study show that heat stress significantly affects reactive oxygen species production and antioxidant parameters. Carotenoid supplementation should be considered to alleviate the impact of these effects.