This study investigated the possible mechanisms for explaining interanimal variation in efficiency of feed utilization in intact male Holstein calves. Additionally, we examined whether the feed efficiency (FE) ranking of calves (n = 26) changed due to age and/or diet quality. Calves were evaluated during three periods (P1, P2, and P3) while fed a high-quality diet (calculated mobilizable energy [ME] of 11.8 MJ/kg DM) during P1 and P3, and a low-quality diet (calculated ME of 7.7 MJ/kg DM) during P2. The study periods were 84, 119, and 127 d, respectively. Initial ages of the calves in P1, P2, and P3 were 7, 11, and 15 mo, respectively, and initial body weight (BW) were 245, 367, and 458 kg, respectively. Individual dry matter intake (DMI), average daily gain (ADG), diet digestibility, and heat production (HP) were measured in all periods. The measured FE indexes were: residual feed intake (RFI), the gain-to-feed ratio (G:F), residual gain (RG), residual gain and intake (RIG), the ratio of HP-to-ME intake (HP/MEI), and residual heat production (RHP). For statistical analysis, animals' performance data in each period, were ranked by RFI, and categorized into high-, medium-, and low-RFI groups (H-RFI, M-RFI, and L-RFI). RFI was not correlated with in vivo digestibility, age, BW, BCS, or ADG in all three periods. The L-RFI group had lowest DMI, MEI, HP, retained energy (RE), and RE/ADG. Chemical analysis of the longissimus dorsi muscle shows that the L-RFI group had a higher percentage of protein and a lower percentage of fat compared to the H-RFI group. We suggested that the main mechanism separating L- from H-RFI calves is the protein-to-fat ratio in the deposited tissues. When efficiency was related to kg/day (DMI and ADG) and not to daily retained energy, the selected efficient L-RFI calves deposited more protein and less fat per daily gain than less efficient H-RFI calves. However, when the significant greater heat increment and maintenance energy requirement of protein compared to fat deposition in tissue were considered, we could not exclude the hypothesis that variation in efficiency is partly explained by efficient energy utilization. The ranking classification of calves to groups according to their RFI efficiency was independent of diet quality and age.

SUMMARY Moringa oleifera is a rich source of antioxidants and a promising feed for livestock, due to significant amounts of protein, vitamins, carotenoids and polyphenols, and negligible amounts of anti-nutritional factors. The current study tested whether ensiling would preserve the antioxidant capacity of M. oleifera plants, and assessed whether Moringa silage, fed as a substitute for maize silage, would confer health-promoting traits and affect milk production in dairy cows. To this end, hand-harvested M. oleifera plants were ensiled, with or without molasses and inoculants, in anaerobic jars at room temperature (25 °C) for 37 days. At the end of the storage period the silages were analysed for pH, lactic acid and acetic acid concentrations, aerobic stability, antioxidant capacity, polyphenols and protein content, and tocopherols and carotenoids concentrations. Moringa silages exhibited higher antioxidant capacity compared with fresh and dried Moringa plants, not related to polyphenol content but presumably attributed to accumulation of amino acids and low molecular weight peptides. Based on these findings, a large-scale ensiling protocol was implemented, followed by a feeding trial for dairy cows, in which Moringa silage replaced 263 g maize silage/kg in the diet. Cows fed Moringa silage had higher milk yield and antioxidant capacity and lower milk somatic cell counts compared with controls, during some stages of lactation. These findings imply that ensiling M. oleifera is an appropriate practice by which health and production of dairy cows can be improved.

Holstein bulls destined for beef production which are unfamiliar with each other are routinely mixed prior to marketing. This practice constitutes a stressful event which affects both animal welfare and meat quality. We questioned whether mixing 34 days before marketing could induce a stress response that would affect the animal performance and pH of meat. For the experiment, 22 Holstein bulls (at a mean age of 7.35±0.07 months and mean weight of 285.5±90 kg) were raised in groups of three and were mixed 34 days prior to marketing to form two groups (n1=13, n2=9). The daily rumination and activity of the bulls were monitored for 20 days before and 33 days post mixing (DPM) and bulls were weighed 1 day before mixing (DBM), 3 and 33 days DPM. Plasma concentrations of non-esterified fatty acid (NEFA), and anti-oxidative capacity in bulls were measured pre- and post-mixing (PM). After slaughter, pH measurements were taken at the m. longissimus thoracis et lumborum (LTL) 24 h after the carcasses were chilled. The results demonstrated that mixing had significantly decreased the calves’ weight gain by 6.2±2 kg at 3 DPM. Daily rumination decreased twofold 24 h PM (P<0.0001). The daily number of steps taken by calves was 3 times higher, and did not return to PM values even 25 DPM (P<0.0001). The mean plasma NEFA concentrations increased from 120±13 to 428±40 µmol/l, 24h PM (P<0.0001), and the anti-oxidative capacity of the serum 24 h PM decreased significantly (P=0.01). Finally, the mean pH value of LTL in meat was 6.5±0.02, greater than what is required for proper acidification. The data collected using precise livestock farming monitoring methods demonstrated the physiological and behavioural outcome of mixing 34 days prior to marketing, which resulted in elevated pH levels in the meat. However, further investigations are required in order to assess the additional impact on meat quality and determine the optimal time needed to recover from mixing in order to maintain good meat quality.

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.

The study investigated whether dietary CPE (concentrated pomegranate peel extract) may mitigate the negative effects associated with group mixing prior to marketing and enhance beef meat quality. Twenty-two bull calves were reared in triplets and divided to control (n = 9) and CPE-treated (n = 13) groups. CPE was supplemented during eight months of rearing, and calves were mixed 34 d prior to marketing to control and treatment groups. Calves were monitored for weight gain, rumination, activity, metabolic and oxidative stress responses. Finally, meat quality traits were examined. The results find that pre-mixing activity (P < 0.0001), non-esterifies fatty acids (P = 0.02) and plasma testosterone (P = 0.005) levels were higher in the treatment group. Following mixing, activity (P < 0.0001) and plasma anti-oxidative capacity (P = 0.05) increased in the treatment compared to the control group. In spite of the above, dietary supplementation of CPE didn't reveal improvement of meat quality parameters by means of meat pH and shelf life. It indicated that improved serum anti-oxidant capacity in the CPE calves was not sufficient to prevent the mixing effects on meat quality. A combined CPE concentration and mixing management should be examined in order to reduce mixing related effects on meat quality.

Thirty-five lactating dairy cows throughout weeks of lactation (WOL) 16 to 30 were used to determine optimal time needed for reliable measurement of performance variables, and to classify the cows into high-, medium-, and low-efficiency groups. Individual performance variables [body weight (BW), dry matter intake (DMI), and milk production] were measured daily with a computerized monitoring system. Body condition was visually scored weekly and used to calculate retained or depleted body energy as a result of fat content change (REF). Milk composition was analyzed weekly. Body weight, DMI, and total recovered energy (RE), which represents energy in milk production plus REF, were summarized weekly. Efficiency was calculated as RE/DMI and as residual feed intake (RFI; i.e., the difference between actual and expected DMI), which was calculated from multiple linear regression of DMI dependence on BW(0.75) and RE. Unexpectedly, it was found that BW did not affect DMI and RE/DMI. Changes and relative changes in phenotypic coefficient of variation and correlations among data from shortened tests ranging from 1 wk (WOL 16) to a sequence of 15-wk tests were used to determine optimal test period durations for 5 traits: BW, DMI, RE, RE/DMI, and RFI. Traits were fitted into a mixed model with repeated measures. For each week, the traits were summarized as a sequence of cumulative data, starting from WOL 16 and cumulated over periods that increased in 1-wk steps up to WOL 16 to 29. Weekly cumulations were compared with those for entire test period (WOL 16 to 30). Consistency of each cow's efficiency classification as high, medium, or low was tested by the total-agreement procedure; the kappa index P-value was used. Throughout WOL 16 to 30, the effects of increasing test period duration on between-animal coefficient of variation differed with respect to the various performance variables and RE/DMI: it tended to change with respect to BW, did not change with respect to DMI, and decreased with respect to RE and RE/DMI. In conclusion, compared with a 15-wk study, a 2-wk study can classify RFI and RE/DMI to 3 efficiency levels, with an individual correlation coefficient of 0.6. When the study was carried out over 3 wk or more, the lowest significant index of the classification was P<0.004, the lowest individual correlation coefficient was 0.65, and its lowest significance was P<0.01. The current study indicated that the insignificant effect of the BW of dairy lactating cows on their DMI should be validated in more studies.

The problem: The same feeding plan can be applied to all animals with individual differences rarely considered. On the contrary, individual intake-based feeding regime claims that if a calf has missed meals and therefore could not consume its daily milk allocation, it should be compensated. Methods: The objective of this study was (1) to compare ‘age-based milk allocation’ with calf individual ‘intake-based milk allocation’ (milk amount depending on the actual consumption). The study achieved its objective through the following phases (2) to design a real-time algorithm, (3) to embed the algorithm in the feeder’s control software, (4) unique mechanical design capable of the computer-controlled feeder. One hundred and fifty male calves were fed. If a calf has not consumed its accumulated milk allocation from birth to date it receives an additional 1.5 liters (L) per day until it has consumed the entire planned amount. Results: Daily weight gain was 691 g/day in the age-based group vs. 794 g/day (SE = 36) in the intake-bared group. The average body weights (BW) at weaning were 76 kg vs. 82 kg. The indicator of health 57% vs. 66%.

We determined the energy costs associated with the activities of beef cows grazing on Mediterranean foothill rangeland covered with herbaceous vegetation. Our central aim was to compare the energy cost coefficients obtained in this study, using relatively large plots, with those obtained in a previous study conducted on smaller plots. Measurements were performed in 3 seasons: in March on nursing cows grazing a 135-ha plot of high quality herbage (11.4 MJ/kg of ME), and in May and September on nonlactating cows grazing a 78-ha plot of low quality herbage (6.2 MJ/kg of ME). Poultry litter manure was given as a supplement in September. Stocking rates on the respective plots were 2.25 and 1.95 ha/cow; 5, 5, and 7 cows were monitored in the respective months. Heat production was determined by continuous monitoring of the heart rate and measurement of the oxygen consumption per heartbeat. Animal location was tracked with global positioning system (GPS) collars equipped with motion sensors. Activity was determined for 5-min intervals using suitable calibration equations. Horizontal and vertical distances traveled were computed by integrating GPS data and plot maps in a geographic information system. Three models were used to estimate the energy cost coefficients of engaging in a given activity and locomotion. Total daily heat production ranged from 644 (September) to 1,014 kJ.kg of BW(-0.75).d(-1) (March; P = 0.04). Estimates of the energy cost coefficients for activity states (kJ.kg of BW(-0.75).d(-1)) ranged from 42.7 to 46.2 for standing, from 84.5 to 92.4 for walking idle, and from 89.4 to 103.2 for grazing; those for locomotion (kJ.kg of BW(-0.75).d(-1).km(-1)) ranged from 2.8 to 2.9 for horizontal locomotion and from 21.4 to 27.9 for vertical locomotion. Estimated cost coefficients of standing, grazing, and horizontal locomotion derived in the present study from animals on relatively larger plots were similar to those of the previous study based on data from smaller plots, but the energy costs of walking idle and of vertical locomotion were greater in the present study than in the previous one. The differences found are associated with the fact that cows in the present study walked for longer periods of time and traveled longer distances in single uninterrupted bouts of locomotion than those in the previous study.

The grazing behavior, diet intake, and energy costs of activity of 2 types of cows grazing a Mediterranean pasture were compared. Fifteen large-frame Beefmaster x Simford (BM) cross cows and 13 small Baladi (Ba) mature cows were allocated to the paddock and monitored during 3 seasons throughout 2006; spring (April), summer (June), and autumn (September). Cows were not given supplemental feed during the spring and summer, but had free access to a poultry litter supplement (25% CP, DM basis) during the autumn. Fecal output and digesta kinetics and feed intake were estimated using indigestible double-marker technique. Cows were fitted for 3 to 4 d in each season with global positioning system (GPS) monitors, with activity monitors attached to one of their hind legs, and with heart rate (HR) monitors harnessed to their chests. Oxygen consumption per heart beat was determined for each cow during each season to enable conversion of the diurnal HR patterns to heat production (HP) units. All the GPS data of cattle locations and the activity, HR, and HP data were synchronized to produce a simultaneous record at 5-min intervals. Partition of time spent by the cows lying down, standing, grazing, and walking without grazing, the horizontal and vertical distances walked per day, and the number of steps taken per day were summed from these records. Multiple regression models were adjusted to refer these activities to the HP and to estimate the specific HP costs per unit of each activity. Accordingly, the daily energy costs of activity were calculated for the 2 cattle breeds on each season as the product of the specific activity and the number of units of each activity per day. Feed intake by Ba cows per unit of metabolic BW was greater (P < 0.001) than that of BM cows in both spring and summer and their apparent selection of greater-quality herbage in spring was greater (P < 0.1) than that of BM cows. The smaller framed Ba cows grazed more hours per day and walked longer distances than the BM cows among all seasons. The specific costs for locomotion were less for the Ba cows.

This study of 17 grazing beef cows on the herbage range was designed to compare previously published data of total daily energy expenditure (EE) and the energy cost of various activities measured in medium-size plots of 28 ha to those determined in larger plots of 145.8 and of 78 ha. Data were obtained by continuously monitoring EE using the heart-rate method and simultaneously monitoring the cows’ location and activity with Global Positioning System (GPS) collars with motion sensors. The cows were monitored through March (lactating cows on high quality herbage), May (non-lactating cows on low quality herbage), and September (non-lactating cows on low quality herbage supplemented with poultry manure). These data were compared to previously published data that were determined on smaller plots. Three statistical models were evaluated, including one which was designated as a stepwise model. Across seasons the cows total daily EE (kJ•kgBW0.75•d-1) ranged from 644 in September up to 1014 in March, and all activities together (grazing, standing and walking) ranged respectively from 58 to 66. The cows` daily vertical and horizontal locomotion ranged from 85 to 124 m and from 2.51 to 3.44 km, respectively. The time spent standing and grazing ranged from 6.6 to 9.0 h and from 7.4 to 11.7 h respectively; horizontal distance traveled while grazing ranged from 1551 to 2327 m/d. These data ranges and effect of month were similar to those measured in comparable months in medium plots. Plot size did not directly affect the duration of time the cows spent on each activity and consequently the energy cost of these activities. However, when the herbage was dry, cows in larger plots grazed longer and expended more energy on grazing activity, and probably consumed more herbage of signicantly better quality than in medium plots, as was expressed by the greater daily energy expenditure.

Daily heart rate (HR) level presents a reliable indication of ruminant heat production (HP) and energy balance status, the basis for animal management decisions. Individual short intervals of measured oxygen consumption per HR (O2 pulse, O2P) are required for the accurate estimation of daily HP, by multiplying O2P with daily HR (the O2P-HR method). The O2P is relatively constant during the day unless the animals are exposed to intensive exercise or heat load. Diet energy concentration and consequently the metabolizable energy intake has minor effect the O2P; however, a significant increase of production rate affects O2P positively. Using a Global Positioning System (GPS) receiver and motion sensors combined with HP measurement by the O2P-HR method enable a reliable estimation of the energy cost of the activities of free-ranging cattle. For grazing cows the sum of energy costs of standing, grazing, and traveling ranged from 38 to 74 kJ•kgBW-0.75• day-1, or 5.8 to 11.4% of the total daily HP.

The energy expenditure and energy cost of activities of grazing beef cows were determined (by using the heart-rate method and GPS collars with motion sensors) on different size plots on Mediterranean foothill herbaceous rangeland, in three seasons. In winter plot size had no effect on the time spent on each activity or on the energy cost of these activities. In the summer, however, when the herbage was dry, cows on large plots grazed longer and expended more energy on grazing activity. It is suggested that on larger plots cows could select herbage of better quality than when grazing smaller plots.

The study was conducted to determine the role of browse in the nutritional status and performance of beef cattle grazing on Mediterranean woodland. Measurements of the botanical intake composition (using N-alkane control release capsules and profile) and of the energy expenditure (EE) and balance (using the heart rate method) were carried out on six pregnant cows in the late summer, and on the same cows when nursing in winter and after weaning in late spring. Broiler chicken manure (poultry litter, PL) was given freely during late summer and in winter. Throughout the three periods the metabolizable energy (ME) concentrations of the consumed diet were 6.23, 8.78, 7.65 MJ/kgDM, respectively and the intakes were 8.59, 9.60, 7.92 kgDM/day, respectively; the ME intake, the EE and the retained energy (all in units of kJ/(kgLW0.75⁎day) were 583, 524 and 58, respectively, in late summer; 960, 634 and 326, respectively, in winter; and 665, 475 and 190, respectively, in late spring. The proportions of woody plants in the consumed diet were 63%, 15% and 59% in the respective periods. The proportion of PL supplement in the diet was 37% in late summer and 35% in winter. We conclude that browse can provide 60% of the MEI, and thus the performance of cows grazed on woodland was comparable with that of cows grazed on herbaceous ranges in this region.

This study with grazing beef cows on the range was designed to explore the possibility of determining incremental energy expenditure (EE) in standing, traveling, and grazing relative to that in lying down, by means of continuous monitoring of EE, location, and activity by the heart-rate method, with Global Positioning System (GPS) collars, and by motion sensors in the GPS collars, respectively. Cows were observed on Mediterranean foothill rangeland covered with herbaceous vegetation through 4 seasons of the year. There were 2 stocking rate treatments, and 14 statistical models were evaluated, including one that was a stepwise model. Total daily EE (TEE) was affected by many interdependent factors apart from activity, including season, stocking rate, herbage quality, standing biomass, and reproductive state of the cow. Each model included all activity variables, plus some of the other factors. Across seasons and treatments TEE, in kJ/(kg of BW(0.75) . d), ranged from 469 in densely stocked, nonlactating cows in June to 1,092 in sparsely stocked, lactating cows in April. The cows' daily vertical and horizontal movements ranged from 75 to 174 m and from 1.5 to 4.2 km, respectively. Within a day, time spent traveling (without grazing) ranged from 0 to 32 min, and grazing time ranged from 4.4 to 12.1 h. Cows spent less time grazing (P < 0.001) in the summer, when herbage quality was low, than in winter and spring. Relative to the baseline EE while lying down, the daily increment incurred by grazing ranged from 13 to 48 kJ/(kg of BW(0.75) . d), and that incurred by grazing, standing, and traveling combined ranged from 38 to 74 kJ/(kg of BW(0.75) . d) or 5.8 to 11.4% of TEE. In conclusion, the estimates of activity costs yielded by 11 of the models were similar to one another, whereas those yielded by the stepwise model and the remaining 2 models were 20% smaller. The cost of grazing activity was estimated to be 6.14 J/(kg of BW(0.75) . m), and that of locomotion during grazing was 6.07 J/(kg of BW(0.75) . m), which agree with values obtained for animals and humans by means of a treadmill. The experimental and statistical approach tested here yielded fairly reliable estimations of energy costs of activities in grazing cows.