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Abstract

The aim of this research was to determine rumination time (RT) and the subsequent milk yield, along with trait changes during lactation dependent on the reproductive status of dairy cows. 728 cows were selected for evaluation in regards to 1–150 days of milk production (DIM). According to their period of lactation and reproductive status, the cows were selected for the following groups: Inseminated (1–35 days after insemination, n=182), Open (45–90 days after calving, n=126), Fresh (1–44 days after calving, n=45); Not-pregnant (>35–60 days after inse- mination and not-pregnant, n=55); Pregnant (35–60 days after insemination and pregnant (n=320). The animals were milked with Lely Astronaut® A3 milking robots. The daily milk yield, rumination time, bodyweight, milk composition (fat, protein, lactose, somatic cell count and gynecological status date) were collected from the Lely T4C management program for analysis. We estimated the lowest productivity in the pregnant cows, where the average milk yield was 28.72 kg and the highest productivity in the fresh cow (p<0.001) (Table 1). The longest rumina- tion time was determined for the inseminated cows, statistically significantly higher at 9.92% (p<0.001) than in the non-pregnant cows, whose rumination time was the shortest. The statisti- cally reliably RT positively correlated with productivity (r=0.384, p<0.001) of the cows (from r=0.302 in the second lactation and r=0.471 in the first lactation to r=0.561 in multiparous cows; p<0.001). Rumination time, according to groups of cows by milk yield, had a tendency to increase (2.14 times) from 202.0± 87.38 (in cows with a productivity of less than 10 kg milk) to 431.6±33.91 (in cows with a milk yield higher than 50 kg) by the linear regression equation: y = 38.02x + 232, R² = 0.721 (p<0.001). The relation between the gynecological status and milk fat-protein ratio of the cows was statistically significant (χ2=2.974, df= 8, p <0.0001). The longest rumination time was determined for the inseminated cows (1 – 35 days after insemination), and the shortest for the not-pregnant cows (>35 – 60 days after insemination and not-pregnant). We can conclude that rumination time, subsequent yield, and milk trait change depends on the period of lactation and reproductive status of a dairy cow.
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Abstract

The objectives of this study were to examine the option of being able to use rumination time (RT) as a form of stress indicator in the first thirty days after calving, and to determine the rela- tionship between rumination time, blood cortisol levels, and lactate concentration levels in dairy cows during the first thirty days after calving. Ninety cows which produced milk (DIM) within 1-30 days were selected and categorised into the following groups: the first group (1) fell within 1-7 days after parturition (dpp) (n=30); the second group (2) fell within 8-14dpp (n=30); and the third group (3) fell within 15-30dpp (n=30) after calving. The cows were milked using Lely Astronaut® A3 milking robots with free traffic. The blood samples were tested using the fluorescence enzyme immunoassay method for cortisol analysis. Lactate concentrations were tested with a Lactate Pro2 ®. The RT increased during all of the exploratory periods (with readings between 1.12-4.90%). A decrease was also observed in the lactate levels (by 1.10 times) and cortisol levels (by 1.98 times, p<0.05) of cows which fell within the 8-14dpp group, when compared to an average of 1-7dpp in the previous study period (15-30dpp). However, lactate concentrations increased (by 1.84 times, p<0.05) as well as cortisol levels (by 2.09 times, p <0.01) when compared with a figure between 8-14 dpp on the average. The results obtained indicate that, RT increased during all exploratory periods, while a decrease by 1.10 times and 1.98 times was observed in lactate levels and cortisol levels, respectively. During the entire period of the study RT was positively correlated with the lactate concentration levels, and negatively correlated with cortisol levels. Within a period of 1-14 days, a negative correlation was determined with lactate levels along with a 15-30dpp-positive correlation coefficient. In conclusion, RT can be used as a kind of stress indicator for cows in the first thirty days after calving; however, further research is required to ascertain this conclusion.
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Abstract

The present study aimed to evaluate the efficiency of hypertonic saline solution (HSS) as a novel treatment of acute ruminal lactic acidosis (ARLA) in cattle, focusing on urinary excretion of acids. Twelve cannulated steers were submitted to experimentally induced ARLA by adminis- tering sucrose into the rumen. Twenty hours later, the cattle were randomly divided into two equal groups. The first group was treated with 7.5% HSS (5 mL/kg) over 15 min, and isotonic saline solution (ISS; 20 mL/kg) for the subsequent 165 minutes. The control group was administered ISS instead of HSS. Rumen and urine samples were collected at different times during the experiment from the baseline to 64 h post-induction. The induction caused a medium-to-moderate ruminal acidosis, and a moderate degree of systemic acidosis and dehydration. Steers treated with HSS increased by 50% its glomerular filtration rate (1.61 mL/min) compared to ISS group (1.06 mL/ min; p<0.03). The overall volume of urine excreted by HSS group was higher than that in ISS group (1.62 L vs 0.7 L; p<0.02). This increase in total volume of urine provided by HSS favored a greater excretion of H+ ions in urine, which was 3.39-fold higher in HSS group (64.3*10-7 vs 18.9*10-7 Mol) as well as lactate (241.7 vs 181.8 mMol) and P urinary excretion (3.8 vs 1.1 mMol) that reduced the urine pH (5.3 vs 5.7). Only the HSS group decreased significantly blood total lactic acid concentration (20.3 %) throughout the treatment. A positive relationship was found between the excretion of urinary phosphorus and urinary pH (r2=0.562). The results showed that this novel treatment with HSS enhanced renal excretion of acids and may be recommended as an additional treatment for cattle with lactic acidosis.
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Abstract

The study was conducted on 26 male, 30 days-old goats, separated from their mothers, divided into two equal groups: I - control and II - experimental, consisting of 13 animals each. All animals were fed with milk replacer, experimental group received additionally 50 g/kg body weight, additive of HMB, for 60 days. The following features were analyzed: body weight, daily increases of body weight, as well as hematological and biochemical blood features. Differences in body weight were found, between experimental and control group, after 60 days of experiment 0.57 kg (p≤0.01). The daily weight gain of experimental animals was higher in comparison with control group. Significant differences were also noted in results of hematological and biochemical blood parameters. Experimental animals showed a higher level of red blood cells as well as number of lymphocytes in comparison with the control group, (p≤0.01).Significant changes were also observed in the level of triglycerides, inorganic phosphorus and protein between both groups. The acid-base balance parameters and ionogram, showed a higher pH level (p≤0.05) HCO – act., HCO – std., BE, ctCO , O sat, K+, Cl– (p≤0.01), while the anion gap (AG) and Na+ were significantly lower in control group (p≤0.01).
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