• Asian-Australasian Journal of Animal Sciences
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• v.32 no.8
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• pp.1122-1127
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• 2019

Objective: The objective of current study was to investigate the lactation performance and rumen fermentation characteristics of dairy cows fed a diet with alfalfa hay replaced by corn stover but supplemented with molasses. Methods: Sixteen Holstein cows in mid-lactation were randomly assigned to 1 of 2 dietary treatments: i) alfalfa based diet (AH), and ii) corn stover based diet supplemented with molasses (CSM). The experiment was conducted according to a $2{\times}2$ crossover design with 22-d each period, consisting of 17 d for adaptation and 5 d for data and samples collection. Results: Dry matter intake and milk yield were higher for cows fed AH than CSM (p<0.01). Milk protein content and nitrogen conversion were higher (p<0.05), while milk urea nitrogen was lower (p<0.01) for cows fed AH than CSM-fed cows. Contents of milk total solids, fat and lactose were not different between two groups (p>0.10). Total rumen volatile fatty acid concentration tended to be higher (p = 0.06) for cows fed AH than CSM-fed cows. Molar proportion of acetate was lower (p = 0.04), but valerate was higher (p = 0.02) in cows fed AH than CSM-fed cows. Rumen concentration of propionate, and isobutyrate, and ratio of acetate to propionate tended to be different (p<0.10) between two groups. The feed cost per kilogram of milk was lower in CSM than AH (p<0.01). No differences were found in feed efficiency and most plasma parameters tested (p>0.10). Conclusion: In comparison with AH diet, CSM diet could be fed to dairy cows without negative effect on feed efficiency, ruminal fermentation, but economically beneficial, indicating that CSM could be an alternative choice for dairy farms instead of AH to feed midlactation dairy cows.

• Korean Journal of Veterinary Service
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• v.47 no.1
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• pp.35-40
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• 2024

Hoof health management plays an important role in dairy farms because lameness can impact productivity via decreased milk yield, reproduction rate, and increased culling rate. Regular hoof trimming can help reduce the incidence of hoof diseases in dairy cows. However, its effects on healthy dairy cows remain unclear. This study investigated the effects of hoof trimming on milk yield, rumination time, and activity in healthy Holstein and Jersey cows. Fourteen cows (7 Holstein and 7 Jersey) without lameness were used in this study. We trimmed the cows and collected data from 3 days prior to 9 days after hoof trimming. Milk yield, rumination time, and activity were measured using automatic milking and health monitoring systems. Milk yield and rumination time decreased, whereas activity level increased on the trimming day compared to the previous days in both breeds, although the difference was not significant. On the days after hoof trimming, milk yield, rumination time, and activity recovered to normal. Especially in Holstein cows, a temporary increase in milk yield was observed compared to that in the pre-trimming period. Hoof trimming did not negatively affect the productivity of dairy cows of either breed. Furthermore, productivity can temporarily increase.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1721-1726
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• 2005

The characteristic smell of cow milk was suppressed when herbs were consumed by lactating dairy cows. But it is unclear whether or not peppermint ingestion affects the nutritional and milk production parameters in lactating dairy cows. The objective of this study was to examine the effect of peppermint feeding to lactating dairy cows on nutrient digestibility, energy metabolism, ruminal fermentation and milk production. Eight Holstein cows were given a diet supplemented with or without 5% of dried peppermint per diet on a dry matter basis. The digestion of nutrients from cows fed the diet with peppermint was significantly lower than that of the control group. Energy loss as methane and methane released from cows receiving the peppermint treatment was significantly lower than that in the control cows. Peppermint feeding to cows resulted in the promotion of thermogenesis. However, ruminal fermentation and milk production were not affected by peppermint feeding. In conclusion, peppermint ingestion by lactating dairy cows reduces the nutrient digestibility and methanogenesis, and changes energy metabolism.

• Journal of Animal Science and Technology
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• v.65 no.1
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• pp.197-208
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• 2023

The objective of this study was to investigate the effects of a traditional dry period (60 d) versus a no dry period (0 d) on the milk production, physiological response, and metabolic status of dairy cows exposed to heat stress during the transition period. Holstein dairy cows (n = 15) with similar expected calving dates were randomly assigned to two different dry period lengths: (1) no dry period (n = 7) and (2) a traditional dry period of 60 days (n = 8). All cows were studied from 8 weeks before expected calving to 10 weeks after calving and experienced heat stress during the transition period. The results showed that cows with no dry period decreased their milk yield in subsequent lactation, but compensated for the loss of milk yield accounted for by additional milk yield before calving. The energy balance at postpartum was improved in cows with no dry period compared to cows with a traditional dry period. There were no significant differences in the physiological response and blood metabolites at postpartum between the dry period lengths of dairy cows exposed to heat stress during the transition period. Taken together, our results showed that omitting the dry period improved the milk production and metabolic status of dairy cows exposed to heat stress during the transition period.

• Journal of Veterinary Clinics
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• v.19 no.2
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• pp.147-152
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• 2002

Ovaries from total 192 slaughtered cows, 154 Korean native cows and 38 dairy cows were collected during the slaughtering process in Kimhae, Changyoung and Yangsan abattoirs in Kyungnam province from January 2001 to January 2002. Rates of pregnant and non-pregnant and ovarian findings were invested. Rates of pregnant cows in 192 slaughtered cows were 12.5% (24 cows) and in difference of cow breeds, 11.0% (17 cows) in 154 Korean native cows and 18.4% (7 cows) in 38 dairy cows from total 192 cows, respectively. Ages of fetuses in pregnant Korean native cows were mostly less than 4 months and ages of fetuses in dairy cows were mostly about 7-8 months. Cows which each diameter of follicles and corpus luteums in same cow was more than 5-6 mm in diameter were 69.8% (134 cows) in total 192 slaughtered cows and in difference of cow breeds, 64.7% (11 cows) in 17 Korean native cows and 57.1% (4 cows) in 7 dairy cows. Mean diameter of foliicles and corpus luteums in Korean native cows are 13.7$\pm$5.6$\times$ 11.2$\pm$4.6mm and 17.5$\pm$4.6$\times$14.6$\pm$4.0 mm in non-pregnat cows, and are 11.0$\pm$4.8$\times$9.1 $\pm$ 2.6mm and 21.2$\pm$2.9$\times$18.3$\pm$ 2.7 mm in pregnant cows, respectively. Mean diameter of follicles and corpus luteums in dairy cows are 15.8$\pm$7.1 $\times$ 14.3$\pm$ 6.0 mm and 20.3$\pm$5.9$\times$16.9$\pm$ 5.8 mm in non-pregnant cows, and are 10.1 $\pm$ 3.0$\times$9.2$\pm$2.3 mm and 23.0$\pm$ 1.7$\times$20.1 $\pm$ 1.3 mm in pregnant cows, respectivley. The above findings indicate that the co-appearance rate of follicles and corpus luteums in same cows are higher in both pregnant and non-pregnant cows. Compared in pregnant and non-pregnant cow ovaries, mean size of follicles are smaller in pregnant cows but size of corpus luteums are more larger in pregnant cows than in non-pregnant cows. Correlation of the follicle size (Y) and corpus luteum size (X) in same cows developed each other in inversive size. Those correlative formulas appeared to be Y = -0.2022X+17.175 in Korean native cows and Y= -0.5754 X+24.153 in dairy cows.

• Journal of Veterinary Clinics
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• v.15 no.2
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• pp.450-454
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• 1998

These studies were performed to find out the possibility of automatic detection of the diseased animal with fever by farmers themselves. Firstly, the body temperature of 331 dairy cows was investigated according to major disease symptoms manifested. Secondly, AD 590 thermometer was used to take the teat temperature of the milking cows to determine the possibility of automatic taking of body temperature while milking. The temperatures of scapha of ear and coccygeal artery part were also taken fur the non-milking dairy cows and Korean native cowl 1. The average body temperature of dairy cows associated with respiratory diseases puerperal disease, or mastitis was higher than normal temperature denoting respectively 39.8,39.6, and $39.3{\circ}C.2.$ The teat temperaure of the milking dairy cows with fever($39.5~39.6{\circ}C$) and the cows with mastitis was respectively 1.02 and 0.56${\circ}C$ higher than that of normal cows. 3. The average teat temperature taken by AD 590 was 33.91, 34.93, and 34.50${\circ}C$ in normal milking dairy cows, cows with fever(39.5~39.6${\circ}C$), and cows with mastitis, respectively. 4. The mean temperatures at scapha and coccygeal part of non-milking dairy cows and Korean native cows were 35.62 and 36.63${\circ}C$, respectively. It was concluded that AD 590 thermometer would be usable for the farmers to automatirally detect the body temperature of dairy cows while milking and subsquently to find the diseased cow with fever and that the scapha of ear and coccygeal artery part of the cattle could be the body parts of simply detecting body temperature of non-milking cattle.

• Animal Bioscience
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• v.34 no.10
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• pp.1600-1606
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• 2021

Objective: This study was conducted to enhance our understanding of nitrogen (N) metabolism and mammary amino acid (AA) utilization in lactating cows with divergent phenotypes of residual feed intake (RFI). Methods: Fifty-three multiparous mid-lactation Holstein dairy cows were selected for RFI measurements over a 50-d experimental period. The 26 cows with the most extreme RFI values were classified into the high RFI (n = 13) and low RFI (n = 13) groups, respectively, for analysis of N metabolism and AA utilization. Results: Compared with the high RFI cows, the low RFI animals had lower dry matter intake (p<0.01) with no difference observed in milk yield between the two groups (p>0.10). However, higher ratios of milk yield to dry matter intake (p<0.01) were found in the low RFI cows than in the high RFI cows. The low RFI cows had significant greater ratios of milk protein to metabolizable protein (p = 0.02) and milk protein to crude protein intake than the high RFI cows (p = 0.01). The arterial concentration and mammary uptake of essential AA (p<0.10), branched-chain AA (p<0.10), and total AA (p<0.10) tended to be lower in the low RFI cows. Additionally, the low RFI cows tended to have a lower ratio of AA uptake to milk output for essential AA (p = 0.08), branched-chain AA (p = 0.07) and total AA (p = 0.09) than the high RFI cows. Conclusion: In summary, both utilization of metabolizable protein for milk protein and mammary AA utilization are more efficient in cows with lower RFI than in the high RFI cows. Our results provide new insight into the protein metabolic processes (related to N and AA) involved in feed efficiency.

• Korean Journal of Veterinary Research
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• v.62 no.2
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• pp.15.1-15.8
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• 2022

The objective of this study was to identify risk factors for repeat breeder dairy cows and their impact on reproductive performance. The characteristics of 1,504 cows, including their peripartum health, nutrition, production, and reproduction, were collected. Cows with metabolic disorder were significantly more likely (odds ratio [OR], 2.47; p < 0.001) and cows with clinical endometritis tended to be more likely (OR, 1.35; p < 0.1) to become repeat breeders than cows without metabolic disorder and clinical endometritis, respectively. Cows initially inseminated > 80 days after calving were less likely (OR, 0.78; p < 0.05) to become repeat breeders than cows initially inseminated ≤ 80 days after calving. As a result, repeat breeding in dairy cows resulted in a 90 day longer (p < 0.0001) mean interval from calving to pregnancy. In conclusion, postpartum metabolic disorder, clinical endometritis, and a short interval from calving to initial insemination were risk factors for repeat breeder dairy cows, resulting in a severely impaired reproductive performance.

• Korean Journal of Veterinary Research
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• v.34 no.1
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• pp.189-193
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• 1994

This study was undertaken to clarify the relationship between the cause of repeat-breeder and the luteal dysfunction in repeat-breeder dairy cows that failed to conceive to three or more artificial insemination(AI) at a regular interval. Progesterone concentrations were measured in milk fat for 20 to 22 days after AI. From the 15 repeat-breeder dairy cows, six cows had a normal progesterone profiles. Five cows showed a delayed rise of the progesterone concentrations until 7 to 10 days after AI, two cows had a comparatively low concentration of milk progesterone below 150 ng/ml through most of the luteal phase, and two cows had a combined pattern of a delayed rise and a low concentration of milk progesterone during luteal phase. It is suggest that luteal dysfunction as indicated by progesterone profiles is one of the causes of repeat-breeder in dairy cows.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.4
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• pp.343-348
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• 2018

In this study, the effect of daily short-distance walking exercise on milk production and metabolic status of the lactating dairy cows was investigated. The experiment was conducted with 10 lactating dairy cows comprising 2 groups (5 dairy cows/group), which were walking activity and non-walking activity. The walking activity (WA) group lactating dairy cows walked outdoors for 1 km/d, and the non-walking activity (non-WA) lactating dairy cows were maintained within a cowshed from $18^{th}$ April to $30^{th}$ May. The activity volume of the neck was not significantly different between the groups, but the activity volume of the leg was higher in WA group compared with non-WA (p<0.05). The rectal temperature was higher in the WA group ($38.6^{\circ}C$) compared with non-WA ($38.2^{\circ}C$) (p<0.05). No significant differences in dietary NE intake, milk production and milk composition were found between the groups. The plasma cortisol concentration was higher in WA group ($2.14{\mu}g/dl$) compared to non-WA ($0.95{\mu}g/dl$) (p<0.05). However, plasma cortisol level of WA dairy cows was significantly decreased as compared with non-WA cows. On the contrary, the level of plasma melatonin was increased in WA cows than that of non-WA dairy cows. It may be interpreted as a change in physical fitness. From this study, we suggest that walking activity can be improved energy balance. Further investigation is needed to determine whether different combinations of distance, rate or doing in morning or afternoon will stimulate energy balance.