Effect of alpine grazing on plasma and hair cortisol, serotonin, and DHEA in dairy cows and its welfare impact.

Through the analysis of blood and hair samples, this study evaluated the effects of grazing in alpine areas on welfare indices and indicators of stress in dairy cows. Twenty-one Holstein dairy cows (body weight: 637 ± 21.5 kg; days in milk: 133 ± 17.7, and second parity) were randomly assigned to 3 groups: control (nongrazing), 12 h of alpine grazing (12 hG), and 24 h of alpine grazing (24 hG). Blood samples for plasma collection were taken for 3 consecutive days at the end of the experiment. Hair samples were collected at the beginning and end of the experiment. Hormone measurements included cortisol, serotonin, and dehydroepiandrosterone (DHEA) in both plasma and hair samples. Plasma cortisol and DHEA levels did not differ among the 3 groups, whereas the plasma serotonin level was higher in the 24 hG group than that in the other groups. The plasma cortisol to DHEA ratio was lower in the 24 hG group than that in the control and 12 hG group. The hair samples taken at the end of the experiment showed that the cortisol level was significantly higher in the control group than that in both of the grazing groups and also higher in the 12 hG than that in the 24 hG group. Hair DHEA and serotonin levels were highest in the 24 hG group. The hair cortisol to DHEA ratio was significantly higher in the control group than that in the 12 hG and 24 hG groups and in the 12 hG group than that in the 24 hG group. Our study showed that grazing dairy cows in alpine areas for 24 h improved their welfare, as indicated by increased serotonin levels in hair and plasma, increased hair DHEA level, and decreased stress indicators, including the hair cortisol level and cortisol to DHEA ratio. Farm facilities should allocate optimal grazing time for optimal welfare of dairy cows.

Wool cortisol is a better indicator of stress than blood cortisol in ewes exposed to heat stress and water restriction.

This study investigated the effect of water restriction on wool and blood cortisol concentrations and water consumption patterns in heat-stressed sheep. Nine Corriedale female sheep (average BW=43±6.5 kg) were individually fed diets based on maintenance requirement in metabolic crates. They were assigned to three treatments according to a Latin square design (3×3) for three periods with a 21-day duration for each period (nine sheep per treatment). Treatments included free access to water (FAW), 2 h water restriction (2hWR) and 3 h water restriction (3hWR) after feeding. Average temperature-humidity index in the experimental room was 27.9 throughout the experiment that defines heat stress conditions. Wool samples were taken at the end of each period on day 21. No differences were found in cortisol concentration in each fragment (dried, washed and residual extract) of wool (P<0.05). Total wool cortisol concentration was higher in the 3hWR group than the other treatments (P<0.05). Blood cortisol was not different among the treatments (P>0.05) and resulted in higher variable data compared with wool cortisol. Blood neutrophils and neutrophil/lymphocyte ratio suppressed in FAW and 3hWR groups compared with the 2hWR group (P<0.05). The duration of water consumption recorded after feeding in the 3hWR group was higher than in the 2hWR group when recorded in the afternoon (P<0.01). Water consumption rate was higher in the 3hWR group than in the 2hWR group (P<0.01). However, total water consumed was lower in the 3hWR group compared with other treatments (P>0.05). It can be concluded that wool cortisol provides more precise and accurate data than blood cortisol during heat stress conditions. Water restriction for 3 h after feeding can act as a stressor and is critical for sheep during heat stress as the consumption of water decreases with restriction.

Limiting Concentrate during Growing Period Affect Performance and Gene Expression of Hepatic Gluconeogenic Enzymes and Visfatin in Korean Native Beef Calves.

This study elucidated the effects of limited concentrate feeding on growth, plasma profile, and gene expression of gluconeogenic enzymes and visfatin in the liver of Hanwoo beef calves. The purpose of this study was to test that reducing the amount of concentrate would partially be compensated by increasing the intake of forage and by altering the metabolic status. The study utilized 20 Korean native beef calves (Hanwoo; 60 to 70 d of age) divided into two groups of 10 calves each for 158 d. Control group calves received the amount of concentrate as per the established Korean feeding standards for Hanwoo, whereas calves in the restricted group only received half the amount of concentrate as per standard requirements. Good quality forage (Timothy hay) was available for ad libitum consumption to both groups. Since calves were with their dam until 4 months of age in breeding pens before weaning, the intake of milk before weaning was not recorded, however, the concentrate and forage intakes were recorded daily. Body weights (BW) were recorded at start and on 10 d interval. Blood samples were collected at start and at 50 d interval. On the final day of the experiment, liver biopsies were collected from all animals in each group. The BW was not different between the groups at all times, but tended to be higher (p = 0.061) only at final BW in control than restricted group. Total BW gain in the control group was 116.2 kg as opposed to 84.1 kg in restricted group that led to average BW gain of 736 g/d and 532 g/d in respective groups, and the differences were significant (p<0.01). As planned, the calves in the control group had higher concentrate and lower forage intake than the restricted group. The plasma variables like total protein and urea were higher (p<0.05) in control than restricted group. The mRNA expressions for the gluconeogenic enzymes such as cytosolic phosphoenol pyruvate carboxykinase (EC 4.1.1.32) and pyruvate carboxylase (EC 6.4.1.1), and visfatin measured by quantitative real-time PCR in liver biopsies showed higher expression (p<0.05) in restricted group than control. Overall, restricting concentrate severely reduced the growth intensity and affected few plasma indices, and gene expression in liver was increased indicating that restricting concentrate in the feeding schemes during early growth for beef calves is not advocated.

Effects of feeding levels of starter on weaning age, performance, nutrient digestibility and health parameters in holstein dairy calves.

To evaluate the effects of feeding four different levels of starter in male Holstein dairy calves, a completely randomized study was conducted, using 28 calves with initial body weight of 40.5±2.4 kg. The animals were fed iso-nitrogenous starter and were weaned when they consumed 350, 500, 650 and 800 g/d of starter for 3 d consecutively. Starter and water were available ad-libitum throughout the experiment. Body weight at pre-weaning (less than 5 wk) and post-weaning (8 wk) was lower in calves that received 350 g/d of starter than in the other treatments (p<0.05). Feed conversion ratio (FCR) was the highest among all treatments in pre-weaning period (p<0.05). Dry matter intake (DMI) at weaning and total DMI was higher in that calves received 800 g/d of starter compared with other treatments (p<0.05). Calves fed 350 and 500 g/d of starter were weaned earlier (p<0.05) and showed lower milk consumption (kg, DM) compared with other treatments whereas no significant difference was observed between calves fed 350 and 500 g/d of starter (p>0.05). Dry matter, organic matter and crude protein digestibilities were lower in calves that received 350 g/d of starter compared with other treatments (p<0.05). No differences were observed in acid detergent and neutral detergent fiber digestibility among all treatments (p>0.05).Treatments had no significant effect on time of starting rumination, respiratory score, and days of drug administration for pneumonia. There were no meaningful differences in feces, fecal odor scores, body temperature, and days of drug administration for diarrhea among all treatments (p>0.05). Total dry matter intake at the end of experiment showed no significant difference among calves fed 600 and 800 g/d of starter, but calves fed 350 and 500 g/d of starter showed more dry matter (DM) intake than calves in the 600 and 800 g/d groups (p<0.05).

Effects of processing of starter diets on performance, nutrient digestibility, rumen biochemical parameters and body measurements of brown swiss dairy calves.

In order to investigate the effect of physical forms of starter diets on performance, weaning age, nutrient digestibility and rumen biochemical factors, 24 female of neonatal Brown Swiss calves (average body weight of 39.5±1.2 kg) were randomly assigned to three treatments. Dietary treatments were mashed (MS), pelleted (PS), and texturized (TS) starter using 8 calves from birth till 90 days of age in each treatment. Diets were formulated to be iso-nitrogenous with 21% crude protein. Based on the experimental results, calves that received PS and TS diets, had significant higher average daily gain (ADG) than those receiving MS (p<0.01). Dry matter intake in calves fed PS and TS was greater than calves fed MS (p<0.05), but there was no significant difference in feed efficiency. Treatments had no effect on initiation of rumination. Weaning age of calves in MS was longer than the other two treatments (p<0.05). Crude protein and organic matter digestibility in MS treated calves were lower than other treatments (p<0.05). No differences were observed in neutral detergent fiber (NDF) and ash digestibility among treatments (p>0.05). Ruminal pH was higher (p<0.01) in MS than the other groups, but ruminal ammonia (g/dl) concentration was not different among the treatments. Body measurements such as body length, pin width, hip width, pin to hip length, size of metacarpus and metatarsus bones, hip height, wither height, stomach size and heart girth were not significantly different among the treatments. Overall, it is concluded that starter diets in the form of pellet and texture can improve performance in neonatal Brown Swiss calves compared to the mashed form.