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The Effect of Rumination Time on Milk Performance and Methane Emission of Dairy Cows Fed Partial Mixed Ration Based on Maize Silage
The objective of this study was to determine the effect of the rumination time on milk yield and composition as well as methane emission during lactation in high-yielding dairy cows fed a partial mixed ration based on maize silage without pasture access. A total of 365 high-yielding Polish Holstein-Friesian multiparous dairy cows were included in the study covering 24 to 304 days of lactation. Methane emission, rumination time, and milk production traits were observed for the period of 12 months. Next, the data from the cows were assigned to three groups based on daily rumination time: low rumination up to 412 min/day (up to 25th rumination percentile), medium rumination from 412 to 527 min/day (between the 25th and 75th percentile), and high rumination above 527 min/day (from the 75th percentile). Rumination time had no effect on milk yield, energy-corrected milk yield, or fat and protein-corrected milk yield. High rumination time had an effect on lower fat concentration in milk compared with the medium and low rumination groups. The highest daily CH4 production was noted in low rumination cows, which emitted 1.8% more CH4 than medium rumination cows and 4.2% more than high rumination cows. Rumination time affected daily methane production per kg of milk. Cows from the high rumination group produced 2.9% less CH4 per milk unit compared to medium rumination cows and 4.6% in comparison to low rumination cows. Similar observations were noted for daily CH4 production per ECM unit. In conclusion, a longer rumination time is connected with lower methane emission as well as lower methane production per milk unit in high-yielding dairy cows fed a maize silage-based partial mixed ration without pasture access.
Different methods of eubiotic feed additive provision affect the health, performance, fermentation, and metabolic status of dairy calves during the preweaning period
Abstract Background This study aimed to evaluate whether different methods of providing eubiotic feed additives to neonatal calves, during the preweaning period, can improve the calves’ health, performance, ruminal fermentation, and metabolic status. Forty-four (3-day-old) Holstein–Friesian dairy calves (22 female and 22 male) were divided into four treatment groups for the duration of the 8-week trial. The eubiotic feed additive consisted of a combination of probiotic Lactobacillus spp. (multiple-strains at a dose of 250 mg/calf/day) and phytobiotics containing rosmarinic acid, as the main bioactive compound (at a dose of 50 mg/calf/day). The groups were named: CON (control, without eubiotic in either the milk replacer or the starter feed), MR (eubiotic in the milk replacer), SF (eubiotic in the starter feed), MRS (eubiotic in both the milk replacer and the starter feed). The individual intake of starter feed and the fecal scores were measured daily, and body weight and biometric measurements were taken weekly until calves were 56 days of age. Blood samples were collected on day 3 and then every 14 days to determine concentrations of insulin-like-growth-factor-I, β-hydroxybutyrate, non-esterified fatty acids, and blood urea nitrogen. Ruminal fluid was collected on days 28 and 56 for short-chain fatty acids, NH 3 -N, and pH measurements. Results The body weight of the calves of the MR treatment group was higher compared to all other groups on days 28 and 56. Including the eubiotic feed additive in the milk replacer increased average daily gain, starter intake, and total dry matter intake from day 29 to day 56 and the overall experimental period compared to the CON group. The calves with MR treatment had lower fecal scores from days 3 to 28, a number of parasite oocysts/cysts per gram of feces on day 28, and the occurrences of fecal consistency scores of 3 (mild diarrhea) and 4 (severe diarrhea) were 3.2 and 3.0 times lower, respectively, compared with the CON group. The MR group had higher ruminal concentrations of short-chain-fatty-acids, propionate, and butyrate on day 56 than the CON group. Adding eubiotics into milk replacer resulted in the highest concentrations of blood insulin-like-growth-factor-I and β-hydroxybutyrate from days 29 to 56 and the overall experimental period. Conclusion The addition of eubiotic feed additives into the milk replacer can improve health, performance, ruminal fermentation, and biochemical blood indices in dairy calves during the preweaning period.
Impact of heat stress during close-up dry period on performance, fertility and immunometabolic blood indices of dairy cows: prospective cohort study
AbstractThis study aimed to investigate whether heat stress, as defined by the temperature-humidity index (THI) during the close-up dry period, had any impact on the productive performance, fertility, and immunometabolic blood indices of dairy cows in the subsequent lactation. Lactation performance was associated with increasing THI values on − 21, − 14, and − 7 d before calving resulting in decreased milk yield by about 2.30, 2.60, and 2.90 kg, respectively. The THI on the − 7 d before the calving was negatively associated with fertility parameters such as delayed first estrus postpartum, an elongated calving interval by approximately 32 d, a higher number of services per conception by 1.00, and an elongated artificial insemination service period, days open, and inter-calving period by about 20, 52, and 52 d, respectively. The study found that the immunometabolic blood indices were associated with increasing THI values during the close-up dry period. The study showed that exposing dairy cows to close-up dry period heat stress had negative consequences on performance, fertility, and immunometabolic blood indices in the subsequent lactation. Therefore, it is recommended that herd management and barn microclimate changes be implemented earlier, starting from the late dry period, to mitigate the negative impact of heat stress.
Sonda przełykowa, dożwaczowa do badania rozwoju oraz diagnostyki przewodu pokarmowego u cieląt i jałówek
The effect of heat stress on performance, fertility, and adipokines involved in regulating systemic immune response during lipolysis of early lactating dairy cows
Opracowanie modelu interpretacji zawartości mocznika w mleku jako biomarkera żywienia i warunków środowiskowych krów mlecznych
The effect of ruminal fluid pH on milk fatty acids composition in cattle
Abstract The present study aimed to evaluate the effects of ruminal fluid pH on the fatty acids (FA) profile of bovine milk. The experiment was performed on 250 Polish Holstein-Friesian cows reared in 11 commercial high-yielding dairy farms. Ruminal fluid samples were collected by rumenocentesis, and fat and FA concentrations in milk were analyzed by Fourier transform infrared spectroscopy. According to ruminal fluid pH, cows were categorized into three pH groups: high pH (pH > 5.8), moderate pH (pH 5.8–5.6), and low pH (pH < 5.6). Milk produced by low-rumen pH cows had a decreased fat content as compared to milk from moderate- and high-rumen pH cows (P≤0.05). Moreover, milk from low-rumen pH cows was characterized by the lowest level of short-chain FA (SCFA; P≤0.05), and consequently, the highest medium-chain FA to SCFA ratio (P≤0.01). The regression analysis showed that these traits explained a small proportion of rumen pH variance, which makes them unreliable indicators of subacute ruminal acidosis (SARA) in dairy cows. However, despite the extensive variability in milk fat composition observed in this study, the effect of ruminal pH on SCFA in all the analyzed herds showed the same trend. Future research aimed to identify SARA biomarkers should therefore be conducted using techniques that allow detection of more individual FA in milk, including SCFA.
The effect of ambient temperature and relative humidity in postpartum dairy cows on productive and reproductive performance and biochemical blood indices in the subsequent lactation
Abstract This study evaluated the effects of ambient temperature (T) and relative humidity (RH) during the postpartum transition period on dairy cows’ milk performance, fertility, and immunometabolic blood indices in the subsequent lactation. A total of 100 Polish Holstein-Friesian cows originating from five commercial dairy farms were categorized into three groups based on average T (<16 °C, 16-20 °C and >20 °C) and RH (<65%, 65-75%, and >75%) on the calving day (0d), and days 7, 14, 21 after calving. With increasing T and RH postpartum, the average daily milk yield during the first 150 days in milk decreased gradually, and the differences between T <16 °C and >20 °C and RH <65% and >75% groups were approx. 3.48 and 2.78 kg, respectively. Milk of cows exposed to increased T and RH was lower in protein, and lactose and higher in fat, milk urea, and somatic cell count. It was also characterized by altered fat composition. Ambient T during the postpartum period had a negative effect on cows’ fertility, which, however, was not affected by RH. The increasing T from <16 °C to >20 °C resulted in the later manifestation of the first estrous (by 27.7 days), a more extended artificial insemination service period (by 19.4 days), a higher number of insemination services per conception (by 0.92 on average), more days open (by 43.3 days), and a longer calving interval (by 43.3 days). Within ranges used in this study, increasing T and RH during the period from d 0 to d 14 postpartum led to decreased body condition score on day 21 by approx. 0.48 and 0.51 points, respectively. Furthermore, T and RH on a calving day were associated with altered biochemical blood indices on d 21 after calving, indicating a more severe negative energy balance and a state of inflammation. The results of this study suggest that dairy cows that calve when T >16 °C should be provided cooling to ensure optimal environmental conditions for high milk production and prevent economic losses associated with reduced milk yield and low fertility.