• Journal of Animal Reproduction and Biotechnology
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• v.37 no.4
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• pp.298-302
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• 2022

South Korea has a temperate climate with four distinct seasons. However, summers are extremely hot and humid, which negatively affects industrial animal production. Hanwoo are native cattle that have traditionally been raised in the natural environment of Korea. The present study investigated the effects of birth and lactation season on the birth and weaning weights of Hanwoo calves. Data were collected from 100 local breeding farms between 2016 and 2021. A total of 56,970 (males, 29,530; females, 27,440) Hanwoo calves were classified according to sex or birth and weaning season (March-May, spring; June-August, summer; September-November, fall; and December-February, winter). The birth weight of Hanwoo calves differed according to the birth season. As such, birth weight of the summer-born calves was the lowest. Additionally, the 90-day weaning weight was positively correlated with birth weight. Interestingly, however, the 90-day weaning weight was not related to the birth season but was related to the 2-month seasonal effect during the lactation period. Furthermore, the 90-day weaning weight was the lowest during the summer lactation period. In the beef cattle industry, daily weight gain is an important economic characteristic related to feed efficiency and growth. Our findings will contribute the management of Hanwoo cattle and analysis of changes in economic characteristics due to high temperatures.

• Animal Bioscience
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• v.34 no.5
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• pp.855-866
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• 2021

Objective: Performance and physiological responses of dairy calves may change by using extruded soybean meal (ESBM) instead of common soybean meal (SBM) in starter feed. The aims of the current study were i) to determine the effect of extrusion processing of SBM on protein electrophoretic size, fourier transform infrared spectroscopy (FTIR) structures and Cornell Net Carbohydrate and Protein System (CNCPS) protein subfractions and ii) to determine the effect of substitution of SBM with ESBM in starter feed of Holstein heifer calves during pre and post-weaning on performance, nutrient digestibility, and blood metabolites. Methods: The SBM was substituted with ESBM at the level of 0%, 25%, 50%, 75%, and 100% (dry matter [DM] basis). Fifty heifer calves (initial body weight 40.3±0.63 kg) were used for the study. After birth, animals were fed colostrum for 3 days and then they were fed whole milk until weaning. Animals had free access to starter feed and water during the study. Results: Extrusion of SBM decreased electrophoretic protein size and increased rapidly degradable true protein fraction, changed FTIR protein and amide II region. With increasing level of ESBM in the diet, starter intake increased quadratically during the pre-weaning period (p<0.05) and body weight, DM intake and average daily gain increased linearly during the post-weaning and the whole study period (p<0.05). Tbe DM and crude protein digestibilities at week 14 and blood glucose and beta hydroxybutyric acid increased linearly in calves as the level of ESBM increased in the diet (p<0.05). Conclusion: Dairy calves performance and physiological responses were sensitive to SBM protein characteristics including electrophoretic size, FTIR structures and CNCPS protein fractions.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.11
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• pp.1569-1576
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• 2011

Accurate assessment of the nutritional status of Nguni cattle is becoming increasingly important in determining their mechanism for adaptation to challenging environments. Changes in body weights and concentrations of total protein (TP), albumin, globulin, glucose, cholesterol, non-esterified fatty acids (NEFA), phosphorus (SIP), calcium and magnesium were determined in Nguni and crossbred calves raised on natural pasture from birth until weaning. At an early age, TP concentration in crossbreds was higher (p<0.05) than that of Nguni calves. However, TP levels increased with age in Nguni calves so that Nguni's had higher (p<0.05) TP levels than crossbreds at weaning. Nguni calves had higher (p<0.05) glucose concentrations than crossbreds in all the ages except in the third month. Serum NEFA levels in Nguni calves were higher (p<0.05) than in crossbreds at all ages except for the second month. Calcium levels decreased (p<0.05) with age in both genotypes. The blood TP concentrations tended to decrease (p<0.05) as body weight increased up to 80 kg, thereafter blood TP concentration increased (p<0.05) as body weight increased. Calcium concentrations in crossbred calves decreased (p<0.05) quadratically as the body weight increased. There was, however, a linear increase (p<0.05) in calcium concentrations in Nguni calves. The higher NEFA and TP concentrations at weaning and the TP increase in Nguni calves beyond 80 kg suggest that Nguni's utilise fibrous feeds better than crossbreds.

• Animal Bioscience
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• v.36 no.2
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• pp.322-332
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• 2023

Objective: We determined the impact of maintaining pasture-based dairy cows and calves together over 100 days on cow milk production, cow and calf behavior, and calf liveweight and carcass quality. Methods: Six Holstein-Friesian cows and their male calves were monitored for 106±8.6 days. Cows were temporarily separated twice a day for milking with calves remaining in the paddock. Cow and calf behaviors were recorded via scan sampling at 6 different timepoints, for the first 7 days and twice a week thereafter. Calves were weighed weekly and immediately processed for meat quality and rumen development analysis at 106±8.6 days. Daily cow milk yields were collected from enrollment until 109±8.6 days (3 days post-weaning). Results: The average daily gain of calves was 1.4±0.73 kg/d, with an average carcass dressing percentage of 59%. Calves had the greatest frequency of observed close proximity to cow and suckling in the first two weeks and decreased with experiment duration. During separation for milking, cow vocalizations and attempts to return to their calf decreased over time. Reticulorumen weight was on target for calf age, but as a proportion of total stomach weight was lower than industry averages of calves the same age due to the larger abomasum. Cows produced an average of 12±7.6 kg of milk yield per day over the 3-days before the calves were weaned and increased to mean of 31±8.3 kg/d the 3 days after weaning, indicating a consumption of close to 20 kg per calf per day. Conclusion: The impact of a pasture-based cow-calf rearing system on cow and calf behavior and the potential for high levels of calf liveweight gain when provided ad-libitum milk and feed were determined. Further research is required to determine the practicality of replicating such systems with large herds and impact on reared calves post-weaning.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.11
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• pp.1557-1562
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• 2017

Objective: This study was conducted to investigate the effects of weaning times on the growth performance, rumen fermentation and microbial communities of yellow cattle calves. Methods: Eighteen calves were assigned to a conventional management group that was normally weaned (NW, n = 3) or to early weaned (EW) group where calves were weaned when the feed intake of solid feed (starter) reached 500 g ($EW_{500}$, n = 5), 750 g ($EW_{750}$, n = 5), or 1,000 g ($EW_{1,000}$, n = 5). Results: Compared with NW, the EW treatments increased average daily gain (p<0.05). The calves in $EW_{750}$ had a higher (p<0.05) starter intake than those in $EW_{1,000}$ from wk 9 to the end of the trial. The concentrations of total volatile fatty acids in $EW_{750}$ were greater than in NW and $EW_{1,000}$ (p<0.05). The EW treatments decreased the percentage of acetate (p<0.05). The endogenous enzyme activities of the rumen were increased by EW (p<0.05). EW had no effect on the number of total bacteria (p>0.05), but changes in bacterial composition were found. Conclusion: From the present study, it is inferred that EW is beneficial for rumen fermentation, and weaning when the feed intake of the starter reached 750 g showed much better results.

• Animal Bioscience
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• v.37 no.2
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• pp.261-273
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• 2024

Objective: The objective of this study was to evaluate the growth performance, rumen fermentation parameters and bacterial community of post-weaning dairy calves in response to five diets varying in corn silage (CS) inclusion. Methods: A total of forty Holstein weaned bull calves (80±3 days of age;128.2±5.03 kg at study initiation) were randomized into five groups (8 calves/group) with each receiving one of five dietary treatments offered as total mixed ration in a 123-d feeding study. Dietary treatments were control diet (CON; 0% CS dry matter [DM]); Treatment 1 (T1; 27.2% CS DM); Treatment 2 (T2; 46.5% CS DM); Treatment 3 (T3; 54.8% CS DM); and Treatment 4 (T4; 67.2% CS DM) with all diets balanced for similar protein and energy concentration. Results: Results showed that calves offered CS had greater average daily gain, body length and chest depth growth, meanwhile altered rumen fermentation indicated by decreased rumen acetate concentrations. Principal coordinate analysis showed the rumen bacterial community structure was affected by varying CS inclusion diets. Bacteroidetes and Firmicutes were the predominant bacterial phyla in the calf rumens across all treatments. At the genus level, the abundance of Bacteroidales_RF16_group was increased, whereas Unclassified_Lachnospiraceae was decreased for calves fed CS. Furthermore, Spearman's correlation test between the rumen bacteria and rumen fermentation parameters indicated that Bacteroidales_RF16_group and Unclassified Lachnospiraceae were positively correlated with propionate and acetate, respectively. Conclusion: The results of the current study suggested that diet CS inclusion was beneficial for post-weaning dairy calf growth, with 27.2% to 46.5% CS of diet DM recommended to achieve improved growth performance. Bacteroidales_RF16_group and Unclassified Lachnospiraceae play an important role in the rumen fermentation pattern for post-weaning calves fed CS.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1735-1740
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• 2005

Forty-two single-bearing and 42 twin-bearing mature Angus${\times}$Hereford cows were allocated, seven per cell to 3 replications of 2 stocking rates (3.2 cows/ha; medium stocking rate [MSR], and 3.8 cows/ha; high stocking rate [HSR]) to graze summer-active and winter-active pastures from late pregnancy to the weaning of their calves. Cow liveweights and growth of calves were recorded as well as estimates of pasture quantity and forage intake. Pasture quantity did not differ in the paddocks grazed by single- and twin-bearing cows during pregnancy, nor effectively did forage intake. Subsequently, intake was higher during mid-lactation especially with twin-rearing cows (25% higher than single-rearing cows at the MSR; 9% at the HSR). However, quantity of pasture decreased for twin-rearing cows and was less than that available to single-rearing cows as lactation progressed. Liveweights of twinrearing cows decreased by 16% from late pregnancy to weaning at the MSR, and by 14% at the HSR, compared to decreases of 1% for single-rearing cows. Twin calves were lighter at birth, had slower growth rates, and were lighter at weaning than single calves. In spite of weaning smaller calves twinning increased the output (kg of calf weaned) per cow and per ha, and increased the efficiency (kg calf weaned per unit of forage eaten by the cow) over single calf production by 46% at the MSR and by 58% at the HSR. Twinning also increased the marginal returns from investment in high input pastures required by the enterprise.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.2
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• pp.165-170
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• 1996

Two experiments were conducted to search factor(s) affecting the plasma allantoin concentration in infant calves. In experiment 1, five male Holstein calves aged 1 week were given only milk replacer free from nucleic acids for 28 days Plasma allantoin concentration varied in a reverse proportion to daily amounts of milk replacer, and the concentration when calves received 750 g/d of milk replacer was significantly lower than that when they received 250 g/d. Contrary to plasma allantoin concentration, glomerular filtration rate(GFR) was directly proportional to daily amounts of milk replacer, leading to a constant filtration of allantoin across the glomeruli. Renal handling of allantion was also unaffected by the amount of milk replacer, resulting in the constant urinary excretion of allantoin. These results suggested that GFR, which was affected by the nutritional status, could affect plasma allantoin concentration. In experiment 2, the effect of age-related changes in nutritional status after weaning on GFR was examined in eight calves weaned at 5 weeks of age. The GFR expressed as body weight basis was lower immediately after weaning, but linearly increased up to the 19th week post-weaning. The present results suggested that the changes in GFR in response to nutritional status would be one of the possible causes of atypical plasma allantoin concentration immediately after weaning. We conclude that plasma allantoin concentration would not be a proper estimator of intestinal flow of microbial protein in cattle.

• Asian-Australasian Journal of Animal Sciences
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• v.1 no.4
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• pp.185-187
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• 1988

A total of 22 energy balance trials were done for calves fed a liquid milk replacer, calf starter and second cut mixed hay during weaning period. Milk replacer supplied 50% of the total dietary energy, calf starter 42% and hay 8% Live weight of calves averaged 64.6 ($S.D.{\pm}7.8$) kg and daily gain 0.54 (${\pm}0.22$) kg. The metabolizability of gross energy averaged 0.751. A regression was calculated relating energy retention (ER, $kJ/kg^{0.75}$) to the intake of metabolizable energy (IME, $kJ/kg^{0.75}$): $$ER=0.69({\pm}0.09)IME-395,\;r=0.888,\;P<0.01,\;S.E.{\pm}7.1$$. Metabolizable energy for maintenance (MEm) was calculated to be $572kJ/kg^{0.75}$ when ER = 0. The amount of IME over MEm for an individual animal (MEg, $kJ/kg^{0.75}$) was regressed on average daily gain (ADG, kg) by the method of regression through the origin: $$MEg=364({\pm}55)ADG,\;r=0.634,\;P<0.01,\;S.E.{\pm}12$$. The amount of ME required for maintenance and growth was estimated to be $936kJ/kg^{0.75}$.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.8
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• pp.1176-1181
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• 2005

This study investigated the effects of restricted suckling (RS) on some physiological and behavioural stress parameters compared to temporal weaning (TW). Twenty Brahman (Bos indicus) cow-calf pairs were assigned to one of two groups: Calves in the RS group were limited to suckle their dams once daily for 30 min during days 30 to 33, while calves in the TW group were removed from their dams during days 59 to 62 postpartum. Heart and respiratory rates, serum cortisol concentration and body temperature were registered in cows and calves. In addition, the number of steps was also registered in calves. All parameters were recorded 24, 48 and 72 h after the beginning of the two treatments, respectively. In TW calves, higher (p<0.05) cortisol concentration and number of steps were recorded in the 1st samples and 1$^{st}$ and 2$^{nd}$ observations, respectively. No difference was found in body temperature between treatments. However, respiration and heart rates differed in the 1$^{st}$ and 2$^{nd}$ observations, respectively. In general, a significant decrease (p<0.05) in these three parameters was observed over time. In cows, no differences were found in cortisol concentration or body temperature between treatments or with time. Heart and respiratory rates were lower (p<0.05) in the TW treatment only 24 h after beginning of treatment. It was concluded that (a) RS resulted in less behavioural and physiological indices of distress compared to TW in calves, although in general, differences were found only in some variables, mainly during the 1$^{st}$ day following start of the treatment, and there in a chance of age effects. (b) Cows were less affected than their young, regardless of the treatment applied.