"Chrono-functional milk": The difference between melatonin concentrations in night-milk versus day-milk under different night illumination conditions.

Pineal melatonin (MLT) is produced at highest levels during the night, under dark conditions. We evaluated differences in MLT-concentration by comparing daytime versus night time milk samples, from two dairy farms with different night illumination conditions: (1) natural dark (Dark-Night); (2) short wavelength Artificial Light at Night (ALAN, Night-Illuminated). Samples were collected from 14 Israeli Holstein cows from each commercial dairy farm at 04:30 h ("Night-milk") 12:30 h ("Day-milk") and analyzed for MLT-concentration. In order to study the effects of night illumination conditions on cows circadian rhythms, Heart Rate (HR) daily rhythms were recorded. MLT-concentrations of Night-milk samples from the dark-night group were significantly (p < 0.001) higher than those of Night-illuminated conditions (30.70 ± 1.79 and 17.81 ± 0.33 pg/ml, respectively). Interestingly, night illumination conditions also affected melatonin concentrations at daytime where under Dark-Night conditions values are significantly (p < 0.001) higher than Night-Illuminated conditions, (5.36 ± 0.33 and 3.30 ± 0.18 pg/ml, respectively). There were no significant differences between the two treatments in the milk yield and milk composition except somatic cell count (SCC), which was significantly lower (p = 0.02) in the Dark-Night group compared with the Night-Illuminated group. Cows in both groups presented a significant (p < 0.01) HR daily rhythm, therefore we assume that in the night illuminated cows feeding and milking time are the "time keeper", while in the Dark-night cows, HR rhythms were entrained by the light/dark cycle. The higher MLT-concentration in Dark-night cows with the lower SCC values calls upon farmers to avoid exposure of cows to ALAN. Therefore, under Dark-night conditions milk quality will improve by lowering SCC values where separation between night and day of such milk can produce chrono-functional milk, naturally rich with MLT.

Short communication: effect of pomegranate-residue supplement on Cryptosporidium parvum oocyst shedding in neonatal calves.

Cryptosporidium parvum is considered one of the most common enteropathogens, responsible for the high incidence of diarrhea and deleterious implications on immunity and health in neonatal calves. The pomegranate is well known for its health-promoting properties. Two experiments were designed to test the antiparasitical and antidiarrheal effects of concentrated pomegranate extract (CPE) supplement in milk in neonatal Holstein calves. Forty-one calves were randomly divided into control (n=20) and treatment (n=21) groups. For the first experiment, the treatment group was supplemented with 3.75% CPE in the daily milk ration, between 3 and 14 d of age, whereas the control group received only milk. Fecal samples were collected between d 5 and 13 to quantify Cryptosporidium oocysts, and the duration and intensity of diarrhea were evaluated. Reduced fecal oocyst count and diarrhea intensity and duration were revealed in the 3.75% CPE calves. No difference was noted in average daily gain between groups. In a second experiment, which was designed to test the effect of a lower CPE concentration (0.6% of daily milk allocation), no effects on fecal oocyst count and average daily gain were observed. However, compared with control, the lower CPE group was characterized by a shorter duration of diarrhea and higher weight gain among males at 14 d of age. These results suggest that the CPE supplement-to-calf milk ratio may potentially alleviate intestinal morbidity caused by Cryptosporidium.

Dynamics of offensive gas-phase odorants in fresh and aged feces throughout the development of beef cattle.

Livestock odors are largely caused by several groups of volatile organic compounds (VOC), including sulfur-containing compounds, VFA, and phenols and indoles. Throughout the growth stages of cattle in the nursery and feedlot, distinctly different diets are formulated to meet the changing requirements of the animal. Because diet composition and manure management are 2 major factors affecting odor emissions, it was assumed that changes in diet composition along the development of calves would affect VOC emissions from fresh and stored manure. In this study, the dynamics of gas-phase VOC in feces from 6 Holstein-Friesian bull calves were followed at 5 ages: 1 to 5 wk (stage I), 6 to 8 wk (stage II, before weaning), 9 to 14 wk (stage III, after weaning), and 15 to 36 wk (stages IV and V). The CP content of the formulated diet decreased from 23.0 to 13.9%. Samples of fresh feces were incubated under either aerobic or anaerobic conditions for 21 d. The VOC were analyzed from the feces headspace by solid-phase microextraction, followed by gas chromatography-mass spectrometry. Distinct changes in gas-phase VOC were observed in fresh and aged feces from calves at different ages. Semiquantitatively (based on comparative peak area counts), the following trends were observed: 1) S-containing compounds were the least dominant in fresh feces at the age of 2 wk (stage I), whereas VFA esters were the most dominant. 2) At the age of 7 wk (stage II), 1 wk before calves were weaned, feces seemed to be the most offensive, presumably because of the difficulty of synchronizing the requirements of the animal and the diet formulation during this stage of rapid development. 3) The VOC decreased during storage of feces under aerobic conditions but significantly increased at all 5 life stages during storage under anaerobic conditions. This study demonstrates that life stage and manure management affect odor emissions from beef fattening operations. Incorporation of the age and diet of calves in odor modeling could improve annoyance predictions.