Effects of the Physiological Status and Diet on Blood Metabolic Parameters in Amiata Dairy Donkeys

Abstract

Body weight changes and blood metabolic parameters in jennies feeding two different diets and in three physiological statuses were investigated (maintenance vs. pregnancy; maintenance vs. lactation). The relationships between blood metabolic profile and milk quality were also evaluated. Fourteen jennies were allocated to two groups (1: pregnant/lactating; 2: non-pregnant, non–lactating). Pregnant jennies and maintenance jennies (during the first 10-week measurement period) fed a diet consisted of ad libitum grass hay (diet 1); lactating jennies and maintenance jennies (during the last 10-week measurement period) fed ad libitum grass hay plus 2 kg/head/day of concentrate (diet 2). Blood sampling was performed on the jennies of both groups; individual milk samples were also collected during the first 70 days in milk. Higher blood NEFA (p < 0.05) were found in pregnant compared to maintenance jennies (diet 1) (68 vs. 37 μmol/L). Lactating jennies showed higher (p < 0.01) average blood NEFA (268 vs. 26 μmol/L) and glucose (66 vs. 55 mg/dL) compared to the maintenance (diet 2). Blood glucose was positively correlated to milk fat (p < 0.05), while negative significant correlations between de novo milk fatty acids and NEFAs were observed. Positive correlations between plasma B-HBA and somatic cell count (p < 0.01) were also found.

Evaluation of Ultrasound Measurement of Subcutaneous Fat Thickness in Dairy Jennies during the Periparturient Period

“…Body condition monitoring is an essential part of dairy cows’ herd management, aiming to continuously assess previous milk production and energy intake [ 14 , 15 ]. Similar to other dairy species, jennies show lower feed intake and an increase in NEFAs concentration during pregnancy and in the first months of lactation, confirming the difficulties in meeting the energy needs [ 25 ]. Various tools for estimating body energy reserve and balance have been studied through the years, such as respiration calorimetry estimation of body water content or measurement of fat cells size considered the gold standard [ 14 , 15 ].…”

“…Knowing the nutritional status and the potential changes in body energy reserve is essential in farm animals’ management, since these greatly affect animal productivity, health, and reproduction [ 11 , 25 ]. Body condition monitoring is an essential part of dairy cows’ herd management, aiming to continuously assess previous milk production and energy intake [ 14 , 15 ].…”

“…It usually presented 2 peaks, depending on the time of parturition: at 60 and 150 d in the summer group and a peak at 90 d in the spring group [ 28 ]. Approaching the peak of lactation might positively influence fat mobilization, since the first months of lactation led to difficulty in meeting the greater energy needs similarly to other dairy species [ 25 , 27 ]. In our study, differences were detected only in two sites probably because these are more susceptible to fat mobilization compared to others [ 12 , 13 ], which could be influenced since the earliest phase of lactation.…”

An Investigation on the Effects of Partial Replacement of Rapeseed Cake in Ayrshire Dairy Heifers’ Diets with By-Product Source of Animal Protein on Body Weight Dynamics, Nutrient Balancing, and Blood Biochemical Markers

“…Thus, heifer rearing is a necessary process on which the high productivity of cows programmed at the beginning of heifer rearing depends [51,52]. Thus, the assessment of blood metabolic profiles is necessary to monitor the health, reproduction and physiological conditions of the animal, which can prevent metabolic disorders in animals [60,61].…”