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1.
The aim of this work was to determine the effect of vacuum level of machine milking on milk yield, milk composition, milking efficiency, somatic cells counts (SCC), and teat end thickness of the Greek mountain breed Boutsiko ewes. Seventy two ewes after a suckling period of 45 ± 5 days were divided into three equal groups of 24 animals for level of milk production, prolificacy and lactation number. The overall experiment lasted 14 weeks. All groups were milked with a pulsation rate of 120/min, pulsator ratio of 50/50, and three vacuum levels of 38, 44 and 50 kPa, respectively, were applied for the three groups. Every two weeks, in a.m. and p.m. milking, measurements were taken for machine milk (MM) and machine stripped milk (MSM), milk composition, SCC, milk emission characteristics (only in a.m. milking) and teat end wall thickness (TEWT) before and after milking. The results have shown that the lower vacuum level of 38 kPa increased (P < 0.05) the percentage of machine milk (82.9%). There were no significant differences among the groups for milk composition, milk flow rate and SCC, but there was a difference in log SCC (P < 0.05) between 38 and 50 kPa. The teat end wall thickness was lower at the lower vacuum level (38 kPa) after milking, and increased (P < 0.001) as the vacuum level was raised to 50 kPa. The findings of this study suggest that with a lower vacuum level of 38 kPa, the ewes are milked better than those with 44 or 50 kPa. Also, the irritation of teats is considerably reduced, while no differences were seen regarding the health of the udder. 相似文献
2.
P.E. Kendall C.B. Tucker D.E. Dalley D.A. Clark J.R. Webster 《Livestock Science》2008,117(2-3):130-138
The objective of this study was to investigate milking frequency as a potential stressor in Holstein–Friesian dairy cows managed in a pastoral farming system. The circadian body (vaginal) temperature rhythm was measured in cows milked twice-a-day (2x) or once-a-day (1x) in two experiments. The first experiment was conducted at peak lactation (50 ± 11 days in milk, DIM) and the second in response to a transition from 2x to 1x milking at mid-lactation (153 ± 21 DIM). At peak lactation, body temperature was continuously recorded for seven days in 40 dairy cows, milked either 2x (two groups, n = 10 per group) or 1x (two groups, n = 10 per group) from the time of calving. At mid-lactation, 60 dairy cows were milked either 2x (four groups, n = 5 per group), 1x (four groups, n = 5 per group) or switched from 2x to 1x on the afternoon of 156 DIM (2x:1x, four groups, n = 5 per group). Body temperature was measured in three of the five cows per group (36 cows in total) for 10 days from 153 to 162 DIM. Milk yield and total grazing time (Experiment 2 only) were recorded in all cows. At peak lactation cows milked 2x had a higher (P ≤ 0.051) mean body temperature between 1600 and 0000 h than 1x cows (38.6 vs. 38.4 °C; SED = 0.03 °C). At mid-lactation, mean body temperature was also elevated between 1600 and 2000 h in 2x cows compared to 1x cows (2x: 38.6 °C, 1x:38.4 °C, SED = 0.04 °C; P < 0.001) and tended (P = 0.083) to be higher in 2x cows between 2000 and 0000 h. On the day the milking frequency was switched from 2x to 1x (156 DIM), mean body temperature still tended to be higher (P = 0.087) between 1600 and 2000 h in cows continuing on 2x compared with 2x:1x and 1x cows. Body temperature in 2x:1x cows on 157 DIM was lower than 2x cows and similar to that of 1x cows, but there was no consistent effect of milking frequency on body temperature from 158 to 162 DIM. Cows milked 2x had a higher daily milk yield than 1x cows at peak lactation and at mid-lactation (peak lactation 2x: 28.1 ± 5.1, 1x: 24.5 ± 4.7 kg milk per day). Time spent grazing between 1600 and 2000 h was initially at least 22 min higher (P = 0.031) in 1x cows than in 2x:1x and 2x cows on 153 DIM but there were no differences (P ≥ 0.107) in the remaining days of the trial. Milk yield in 2x:1x cows declined rapidly on 156 DIM to be lower (P < 0.001) than both 2x and 1x cows but from 157 DIM began to follow the same pattern as 1x cows. In conclusion, milking frequency had an effect on the circadian body temperature rhythm, particularly in the late afternoon and evening. There was a decline in body temperature from 1600 h if milking frequency was reduced, but this change was not explained by treatment differences in time spent grazing during the same period. The alterations in the circadian body temperature rhythm with milking frequency were likely due to differences in metabolic activity and internal heat production associated with locomotor activity and relative milk production rather than physiological stress per se. 相似文献
3.
The objective of the experiment reported here was to establish the effect of canola meal supplements of different protein degradability on the performance of grazing dairy cows with different body condition scores (BCS) in early lactation, and to compare this with feeding a cereal grain supplement instead. The experiment included a total of 72 cows in six treatments in a 2 * 3 factorial design, incorporating two BCS at calving (4.1 and 5.6 units on an 8-point scale), and three early lactation pelleted supplements. The three pelleted supplements were 100% wheat (wheat supplement), 50% wheat and 50% untreated mechanically extracted canola meal (a rumen degradable protein supplement), and 50% wheat and 50% canola meal that had been subjected to additional heat and pressure (a rumen undegradable protein supplement). It was hypothesised that fat cows would perform best with the treated canola meal supplement, which provided most rumen undegradable protein, whereas the type of protein would not be important for thin cows, and neither would the type of supplemental energy. Cows grazed pasture after calving at a daily pasture allowance of 35–40 kg DM/cow and were offered 6 kg concentrates each day. Cows were fed these diets for 92 days on average, from calving until three weeks into the mating period. Both canola meal-based supplements resulted in higher (P < 0.05) daily milk production than the wheat supplement (33.3 and 34.0 v. 30.5 kg/cow) in both thin and fat cows. Body condition score at calving positively (P < 0.05) affected average milk yield (31.6 v. 33.7 kg/cow), however, there was a time × BCS × supplement interaction whereby the fatter cows benefited from the use of either of the canola meal supplements for a longer period than did the thin cows. Average milk fat concentrations were greater (P < 0.05) where the canola meal supplements were fed (39.3 and 39.6 v. 35.6 g/kg), and in fat cows relative to thin cows (40.0 v. 36.3 g/kg). Serum urea concentrations were significantly (P < 0.05) lower in cows fed wheat than in those fed either of the canola meal supplements (3.1 v. 4.3 and 4.2 mmol/L). Serum β-hydroxybutyrate concentrations were lowest (P < 0.05) where wheat pellets were fed, and highest (P < 0.05) where treated canola meal pellets were fed, and plasma glucose concentrations were highest with wheat and lowest with the treated canola meal pellets. Thus, the hypothesis was not supported by the results of this experiment. 相似文献
4.
Sixty-eight multiparous grazing dairy cows were randomly allocated to two precalving pasture allowances to achieve differential dry matter intakes (DMI) for 29 ± 7.7 d precalving (Low or High DMI; 4.8 or 11.9 kg DM). At calving, cows within each precalving treatment were randomly allocated to one of two levels of feeding (Low or High DMI; 8.6 or 13.5 kg DM) for 35 d postcalving in a completely randomized design and a 2 × 2 factorial arrangement of treatments. Following treatments all cows grazed together and were fed pasture and pasture silage. Daily milk yields were recorded, and fat, protein and lactose concentrations determined weekly for 15 weeks. Blood was sampled weekly pre- and postcalving and analysed for indicators of energy status, growth hormone (GH) and insulin-like growth factor-1 (IGF-1). Body condition score (BCS) at calving was reduced by precalving restriction (P < 0.001; 2.8 and 3.0 for precalving Low and High treatment groups, respectively). Precalving restriction reduced milk fat production by 8.4% during the first 5 weeks postcalving, but differences were not significant subsequently. Postcalving feed restriction reduced yield of fat corrected milk (FCM), fat and protein by 23, 21 and 28%, respectively, during the first 5 weeks postcalving. Decreased (P < 0.05) yields of FCM, fat and protein (11, 10 and 9%, respectively) were also evident for 10 weeks after the feed restriction finished. There was a tendency (P < 0.1) for a precalving × postcalving DMI interaction in milk protein yield during the first 5 weeks of lactation with no effect of precalving level of feeding in cows that were restricted postcalving. The plasma concentrations of non-esterified fatty acids (NEFA), β-hydroxybutyrate (BOH) and GH were elevated in restricted cows precalving, and IGF-1 concentration was reduced. Plasma NEFA and BOH concentrations were elevated postcalving in restricted cows, but no effect of postcalving DMI on GH or IGF-1 concentration was evident. Results suggest that under grazing systems milk production responses to precalving DMI are small, but energy restrictions in early lactations result in significant carryover effects in milk production. 相似文献
5.
Calcium (Ca) requirement increase rapidly by pregnant ewes at late gestation as a result of high fetal growth. Furthermore, Ca deficiency results in poor growth and bone development in growing newborn lambs. The aim of this study was to evaluate the effect of calcium supplementation (Calcium carbonate–CC) and vitamin AD3E injection (75,000 IU/shot) to pregnant Awassi ewes at late gestation (− 45 days prepartum) on their mineral levels and performance of their newborn lambs. Forty pregnant Awassi ewes at late gestation (65 ± 6.1 kg) were selected before parturition (− 45 days; using hormonal sponges for estrus synchronization) and randomly divided to 4 dietary treatments. The treatments were: group 1 Control (1.4% CC); group 2 (2.4% CC); group 3 (1.4% CC + 2 shots vitamin AD3E at − 45 and − 21 days prepartum); group 4 (2.4% CC + 2 shots vitamin AD3E at − 45 and − 21 days prepartum). Blood samples were collected from ewes (− 45, 0 days prepartum: 30 and 60 days postpartum) and lambs (0, 30 and 60 days old). Average milk yield and samples were collected. Body weights of lambs were taken at birth, 30 and 60 days old. Blood serum and milk samples were prepared and analyzed by AAS for Ca, Mg, Co, Mn and Cu concentrations.Calcium concentrations in bloods serum of ewes, 0 and 60 days postpartum, and lambs at weaning (60 days old) from group 4 were significantly (P < 0.05) higher compared to other groups. No significant effect (P > 0.05) of treatment on Co, Mg and Cu in blood serum of ewes and lambs except for Cu concentration in ewes. Moreover, a significant increase (P < 0.01) in milk inorganic% (30 and 60 days samples) in ewes from group 2 when compared with other groups. The average milk yield (AMY) of ewes from group 2 and 4 at late stage of lactation (45–60 days) were significantly higher (P < 0.05) compared to groups 1 and 3. In addition, Ca% in colostrums samples from ewes in groups 2 and 4 were significantly higher (P < 0.01). The average daily gain (ADG) and total body gain for lambs up to weaning (60 days old) were significantly higher (P < 0.05) in groups 1 and 2 compared with the other groups.In conclusion, increasing level of Ca intake in feed of Awassi ewes at late gestation, with or without vitamin AD3E injections, improve the calcium concentration in colostrums and blood serum of ewes and their lambs without negative effect in their health and performance. 相似文献
6.
The objectives of this study were to investigate the effects of genetic capacity on abomasal and intravenous infusions of wheat starch or glucose (CHO) or a mixture of amino acids (AA) on milk production, nitrogen utilization efficiency, plasma metabolites and hormones of dairy cows in early and late lactation. Eight cows from two genetic lines selected for low (L) and high (H) milk production were used in a 4 × 4 Latin square design. The mean differences in pedigree index between the two groups were 1639 kg milk and 55 kg protein yield based on 305 days lactation. Infusions were: 1) starch in the abomasum (SP), 2) glucose in the blood (GB), 3) AA in the abomasum (AP), and 4) AA in the blood (AB). The experiment was conducted in early lactation (start: 57 ± 4 and 52 ± 2 days postpartum, 31.3 ± 2.8 and 34.7 ± 1.4 kg milk for L and H cows, respectively) and repeated with the same animals and treatments in late lactation (start: 168 ± 4 and 163 ± 2 d postpartum, 21.0 ± 1.9 and 23.8 ± 0.7 kg milk for L and H cows, respectively). Daily amounts infused were on average 354 and 258 g in early and late lactation, respectively. The cows were restrictively fed a basal diet consisting of concentrate mixture and grass silage (55:45 on DM basis). Differences in milk yield and ECM between the genetic groups were 3.7 and 3.3 kg in early lactation and 2.9 and 2.0 kg in late lactation, respectively, but the difference was not significant (P > 0.10). Minor effects of genetic group were found in milk production and plasma metabolite concentrations. However, the extraction rates of EAA, BCAA, NEAA and TAA were higher (P < 0.05) in H cows than in L cows in early lactation but not in late lactation. OM and CP digestibility and hormones were affected by genetic group or genetic group × treatment interaction. It is concluded that genetic capacity is important for digestion and metabolism of nutrients, and particularly, how hormone levels are influenced by different nutrient supply. 相似文献
7.
Energy balance, milk production and reproduction in grazing crossbred cows in the tropics with and without cereal supplementation 总被引：2，自引：0，他引：2
Carlos Aguilar-Prez Juan Ku-Vera Fernando Centurin-Castro Philip C. Garnsworthy 《Livestock Science》2009,122(2-3):227-233
The aim of this work was to study the effect of parity order and reproductive management systems on rabbit production performance. A total of 73 rabbit does (I group) were submitted to a 35-day intensive rhythm [artificial insemination (AI) on day 4 post-partum (pp) and weaning at 25 days of lactation], and 108 rabbit does (SI group) were submitted to a 42-day semi-intensive rhythm (AI on day 11 pp and weaning at 35 days of lactation) during 9 months. Primiparous does had the lowest live body weight at parturition (P < 0.0001) and at 21 days of lactation (P < 0.0001). They also had lower milk production (P < 0.0001) than does with later parities. I group animals needed a higher number of AI than SI group to become pregnant (1.70 ± 0.03 vs. 1.39 ± 0.03; P < 0.0001: especially after the third). Prolificacy was not affected by the management system. Parturition interval (PI) was longer than expected in both groups [56.0 ± 1.4 and 50.9 ± 1.38 days in I and SI groups, respectively (P < 0.05)]. Mean productivity, estimated as number of weaned rabbits per female and year, was 12 kits higher in rabbit does of the SI group (P < 0.05). From the third parturition onward, an increase in live body weight of kits at different ages was observed. At 21 (P < 0.05) and 25 days of age (P < 0.01), kits from the I group rabbit does weighed more than those from the SI group; however, the latter showed a higher weight at 35 (P < 0.05) and 60 days of age (P < 0.05). Rabbit does with two or three parturitions had higher litter size at 21 and 25 days of age (P < 0.0001 and P < 0.001, respectively). Kit mortality between 21 and 25 days of age and between 35 and 60 days of age was not affected by treatments but was higher in the I group between 25 and 35 days (18.2 vs. 5.03% in the I and SI groups, respectively; P < 0.0001) and as age of does increased (P < 0.05). In light of these results, we could conclude that long term doe reproductive performance is negatively affected and litter viability decreased when using intensive compared to a semi-intensive reproductive management. 相似文献
8.
The effect of including high or low tannin forage peas as an alternative to soyabean meal on performance and N efficiency was investigated using 18 dairy cows in two Latin square design studies. Two varieties of forage pea; Racer (coloured flowers; high tannin) and Croma (white flowers; low tannin), were ensiled 12 weeks post sowing. The in situ degradability characteristics of the pea silages were determined using 4 cannulated sheep. The low tannin forage had a higher soluble N (a) fraction and a greater extent of degradation (a + b), resulting in a greater amount of N being predicted to be released in the rumen than the high tannin forage. In experiment 1, cows were fed one of three treatments in each of 3 periods of 28 d duration in a Latin square design; grass silage/whole-crop wheat (0.50:0.50, DM basis) and 8 kg/d of a high protein concentrate (GWH); grass silage/whole-crop wheat/high tannin forage pea silage (0.25:0.25:0.50 respectively, DM basis) and 8 kg/d of a high protein concentrate (HTH) or 8 kg/d of a low protein supplement (HTL). The inclusion of forage peas increased (P < 0.05) DM intake by 1.2 kg DM/d, but there was no effect of dietary treatment on milk yield (average of 23.0 kg/d), composition or live weight change. The efficiency of use of dietary N (N output in milk/N intake) was highest (P < 0.001) in cows when fed GWH (0.289) and lowest in HTH (0.234). In experiment 2, cows were fed one of three treatments in each of 3 periods of 28 d duration in a Latin square design; grass silage/whole-crop wheat (0.50:0.50, DM basis) and 8 kg/d of a high protein concentrate (GWH); grass silage/whole-crop wheat/low tannin forage pea silage (0.25:0.25:0.5 respectively, DM basis) and 8 kg/d of a high protein concentrate (LTH) or 8 kg/d of a low protein concentrate (LTL). Compared with GWH, the inclusion of forage peas increased (P < 0.05) DM intake by 2.0 kg/d, but there was no effect of dietary treatment on milk yield (average of 24.5 kg/d). Milk fat content was highest (P < 0.05) in cows when fed LTL (45.7 g/kg) and lowest in LTH (41.9 g/kg), but there was no effect (P > 0.05) of treatment on daily fat yield or any other milk component. The efficiency of dietary N use was highest (P < 0.001) in cows when fed GWH (0.300) and lowest in LTH (0.234). It is concluded that either high or low tannin forage pea silages can replace approximately 1.1 kg/d of soyabean meal in the diet of mid-late lactation dairy cows without affecting animal performance, but N efficiency for milk production is decreased. 相似文献
9.
This study analysed feeding patterns and feed selective consumption by loose-housed lactating dairy cows fed diets based on maize silage (MS) with different particle length (PL) to establish its effects on overall dry matter intake (DMI) and productive performance. Twelve multiparous Holstein cows were offered a total mixed ration (TMR) with three different PL of MS at harvesting (i.e., long, medium, and short). Results demonstrated greater numbers of day-time meals (i.e., 07:30–19:00 h) when PL was decreased from long to medium (P < 0.05). Night-time (i.e., 19:00–06:30 h) changes in the feeding pattern included an increased amount of feed per meal (P < 0.05) and a tendency to increase eating time per meal (P < 0.10) in cows fed the short-PL diet. Lowering the PL of MS also lowered the selective consumption against physically effective fibre larger than 1.18 mm (peNDF> 1.18; P < 0.05) and in favour of fine particles (i.e., particles passing through 1.18 mm screen; P < 0.01). Decreasing PL of MS from long to medium and short increased daily DMI as well as the intake of energy and other nutrients contained in the diet including the amount of peNDF> 1.18 (P < 0.01). The decrease in the PL of the diet also was associated with increased milk protein and lactose yield and milk urea nitrogen (P < 0.05). The actual milk yield and fat-corrected milk were not affected by the diet (P > 0.10). Although lowering of the PL tended to increase daily milk energy output (P < 0.10), the ratio between energy milk output and the energy intake was linearly decreased (P < 0.01), indicating a lower milk efficiency for the lower-PL diets. In conclusion, particle length of MS in a TMR has the potential to modulate circadian feeding patterns, selective consumption of the feed, daily DMI, and milk composition in high-producing dairy cows. 相似文献
10.
To investigate the relationship between the parameters of feeding behaviour and feed intake, 70 lactating dairy cows (23 primiparous and 47 multiparous) were monitored from the 2nd to 15th week of lactation. Data were collected by using an automatic feeder and electronic identification of individual cows from 10 July 2005 to 16 January 2006. The resulting data of the cows in primiparous and multiparous condition were categorised into groups based on the mean of their milk yield over the first 15 weeks of lactation: primiparous cows with below-average milk yield (LP) and above-average milk yield (HP) with an average of 28.44 and 34.31 kg energy-corrected milk (ECM) per day, respectively, and multiparous cows with below-average milk yield (LM) and above-average milk yield (HM) with an average of 38.70 and 44.49 kg ECM per day, respectively. The parameters of feeding behaviour were calculated based on the estimated meal criterion from pooled data. Parity, level of milk yield, and day had significant effects on some of characteristics of feeding behaviour and feed intake parameters. There was no significant difference in meal duration either between primiparous and multiparous cows or between LP and HP. However, a significant difference between LM and HM was observed. Cows in HM had shorter feeding times but a larger meal size, higher DMI, and feeding rate. Moreover, these cows displayed a stronger correlation between meal duration, daily mealtime and daily feed intake (r = 0.37 and 0.50, P < 0.001, respectively) than any other cow or group of cows of the study. Meal duration, daily mealtime, meal size and daily DMI increased on average about 32%, 20%, 35%, and 22% respectively, considering all milk yield groups from the 2nd to 15th week of lactation. 相似文献
11.
A. Summer R. Saleri M. Malacarne S. Bussolati V. Beretti A. Sabbioni P. Superchi 《Livestock Science》2009,124(1-3):107-111
In sows, a strong relationship exists between body condition and reproductive efficiency and milk yield. Leptin may act as a metabolic gate which permits the activation of reproductive axis: in the sow, serum concentration of leptin was positively correlated with adiposity at farrowing. An interesting aspect useful to clarify the biology of leptin, was the discovery that the placenta expresses the ob gene, the ob receptor gene and it is a site of leptin production, suggesting a possible role of the hormone in fetal growth; after birth, the placenta functions were taken over from milk, especially to the delivery of maternal hormones and growth factors to the neonate. The exact role of maternal leptin in the physiology of neonatal piglets remains to be determined. Our aim was to evaluate if maternal leptin levels at the beginning of lactation and at weaning could predict the resumption of cycle activity and/or the piglet gain. Thirty-eight Large White × Landrace pregnant sows (16 nulliparous and 22 pluriparous) were used. Blood samples were taken from sows and piglets at d 5 and d 21 after farrowing; in the same days, milk samples were taken after oxytocin injection by means of complete manual milking of all mammary glands of one side. On the basis of the blood leptin at d 5, sows were divided into 3 groups (Low: < 2.3 ng/ml; Medium: 2.3 to 2.6 ng/ml; High: > 2.6 ng/ml). Our results show a correlation at d 5 between backfat thickness and blood leptin (r = 0.342; P < 0.05). The resumption of the cyclic activity was faster in sows with a leptin level at d 5 greater than 2.3 ng/ml (P < 0.01). Milk composition at d 5 and 21 was not affected by parity and leptin. Piglet ADG was significantly (P < 0.05) influenced by sow leptin groups (0.180 kg day− 1 for piglets from Low group and 0.224 for High group). Piglets weaned by High group sows have shown a greater blood leptin content at weaning (P < 0.01) than other groups. In conclusion we have found a significant correlation between leptin and productive and reproductive performances of pigs. This paper underlines the pleiotropic actions exerted by leptin in the productive sow. 相似文献
12.
Supplementation of dairy cows with a fish oil containing supplement and sunflower oil to increase the CLA content of milk produced at pasture 总被引：1，自引：0，他引：1
It has been shown that the cis 9, trans 11 isomer of conjugated linoleic acid (CLA) can be increased in milk by supplementation with fish oil and vegetable oils. Feeding a high level of oil, however, can impact negatively on gross milk composition. The principal aim of this study was to determine if relatively low levels of fish oil or sunflower oil, either alone or in combination, offered to dairy cows on pasture would increase the C18:2 cis 9, trans 11 CLA concentration in milk. Forty autumn-calved cows on a diet of grazed grass were assigned to 4 supplementation treatments: (i) No supplement (P), (ii) 255 g/day of sunflower oil (SO), (iii) 255 g/day of sunflower oil + 52.5 g/day of fish oil (SOFO), and (iv) 105 g/day of fish oil (FO). The fish oil was supplied in a proprietary product called Omega-3 Supplement which is a mixture of marine oils and an extracted oilseed meal and contains 500 g/kg of oil. The oils were fed in a concentrate mixture, which was offered at a rate of 3.0 kg/cow per day. The production of the cows was measured for 54 days and the milk fatty acid composition was determined on day 0 (immediately before the supplements were introduced) and on days 14, 28 and 42 after the treatments were imposed. Supplementation increased the yield of milk (P < 0.01), protein (P < 0.05) and lactose (P < 0.001), decreased milk fat (P < 0.05) and protein (P < 0.01) concentrations and increased (P < 0.01) lactose concentration. Type of oil did not significantly affect any production variable. The concentration of C18:1 trans 9 + C18:1 trans 11 (mainly C18:1 trans 11) (P < 0.001) and C18:2 cis 9, trans 11 CLA (P < 0.01) were greater on supplemented treatments than on P and the concentration of both were greater (P < 0.05) on FO than on SO. The results confirm that the concentration of C18:2 cis 9, trans 11 CLA can be increased further, from an already relatively high concentration in milk from pasture, by offering supplements containing a low level of fish oil either alone or in combination with sunflower oil. 相似文献
13.
Effects of malic acid on feed intake, milk yield, milk components and metabolites in early lactation Holstein dairy cows 总被引：2，自引：0，他引：2
C. Wang Q. Liu W.Z. Yang Q. Dong X.M. Yang D.C. He K.H. Dong Y.X. Huang 《Livestock Science》2009,124(1-3):182-188
The objective of this study was to evaluate the effects of malic acid (MA) on feed intake, milk yield and composition, blood metabolites and energy balance in early lactation Holstein dairy cows from 1 to 63 day in milk (DIM). Twenty-eight multiparous Holstein dairy cows, blocked by lactation number, previous 305-d mature equivalent milk production, and expected calving date, were arranged into four groups in a randomized block design. Treatments were: control (without MA), LMA, MMA and HMA with 70, 140 and 210 g malic acid per cow per day, respectively. The supplement of food grade MA (99.8% of MA) was hand-mixed into the top one-third of the daily ration. Cows were fed ad libitum a total mixed ration consisting of equal proportion of forage and concentrate. Milk yield increased (P = 0.04), but feed intake and milk components were not affected (P > 0.05) by MA supplementation. The energy balance, expressed as the difference between energy input and output, tended to be higher (P = 0.08) for MA supplemented cows during the 63-DIM period MA and supplemented cows showed a trend (P = 0.07) toward less loss of BW during the 63-day period, especially during the first 21-day of lactation. Concentrations of plasma glucose and serum insulin were higher for cows fed LMA, MMA, and HMA relative to control and linearly (P < 0.01) increased with increasing MA supplementation. Concentrations of non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA) and urine ketones were lower for MA-supplemented cows at 7, 14 and 21 DIM of lactation and linearly (P < 0.01) decreased with increasing MA supplementation. Although feed intake was not affected, milk yield increased, MA-supplemented cows experienced higher concentrations of plasma glucose and serum insulin, lower concentrations of plasma BHBA and NEFA, and lower concentrations of urine ketones, suggesting that nutrient digestibilities and energy availability may have been improved. 相似文献
14.
The objectives of this study were to examine the effect of parity and days in milk (DIM) on dry matter intake (DMI) and actual milk yield (MYAct) of grazing spring calving dairy cows in early lactation (< 100 DIM) and to develop equations to predict DMI and milk yield for grass based systems of milk production. A dataset containing 335 observations from 134 Holstein Friesian dairy cows was assembled from two early lactation grazing studies. Observations were available for primiparous (n = 130) and multiparous (n = 205) cows during periods of DMI measurement using the n-alkane technique. Animal performance was divided into two classes of DIM: less than 50 DIM (< 50 DIM) or between 51 and 100 DIM (> 50 DIM). Parity and DIM had a significant effect on grass DMI (GDMI), total DMI (TDMI), MYAct and milk composition. TDMI increased with parity and DIM and ranged from 13.4 kg/cow per day (primiparous animals, < 50 DIM) to 20.1 kg/cow per day (multiparous animals, > 50 DIM). Actual MY increased with parity and decreased with DIM (range: 24.1 kg/cow per day (primiparous animals, > 50 DIM) to 33.0 kg/cow per day (multiparous animals, < 50 DIM)). Multiparous cows had greater bodyweight (BW) and lower BCS than primiparous cows. In the early lactation period a number of variables had a significant effect on GDMI, TDMI and milk yield. These predictor variables included BW, BCS, potential milk yield (MYPot), DIM, daily herbage allowance (DHA; > 4 cm), concentrate level and parity. The equations accounted for 79%, 83% and 86% of the variation in GDMI, TDMI and milk yield, respectively. Actual milk yield was always below the MYPot of the cows, the mean difference was 5.8 kg/cow per day. As DHA and concentrate level increased, the difference between MYAct and MYPot reduced. This study supports the concept that immediately post-calving offering a grass based diet with a medium level of concentrate supplementation is sufficient to support high milk production in grazing dairy cows. 相似文献
15.
An experiment was conducted to evaluate the effect of a Ca salt supplement on lactating Awassi ewes and their lambs. Ninety Awassi ewes (average BW = 55 kg ± 1.13) were allocated into three treatment groups of 30 each; 0%, 3%, or 5% Ca salt supplemented groups. The experiment started at lambing and lasted for 60 d. During this period, milk production and composition, final body weights, total feed intake, serum cholesterol and triglycerides, weaning weights of lambs, and milk fatty acid profile were tested. Milk production and energy corrected milk increased (P < 0.05) with Ca salt level in the diet. Milk fat content was higher (P < 0.05) at 3% treatment group compared to 0% and 5% treatment groups. However, no differences were detected in content of crude protein and total solids, and milk energy value. Milk fat yield (g/d) increased (P < 0.05) as Ca salt in the diet increased. Final body weight was higher (P < 0.05) for 5% group when compared to the 0% group with no differences between the 3% group when compared to 0% and 5% groups. No differences were observed in feed intake of ewes. Metabolizable energy intake was greater (P < 0.05) for the 3% and the 5% treatment groups when compared to the 0% treatment group. Feed to milk ratio increased (P < 0.05) when increasing the level of Ca salt in the diet. Serum cholesterol was greater (P < 0.05) in the 5% treatment group than the 0% and 3% treatment groups for ewes and lambs. Serum triglyceride was similar among treatment groups in ewes whereas serum triglyceride was greater (P < 0.05) for lambs in 5% treatment group than 0% and 3% treatment groups. However, serum triglyceride was similar in ewes among treatment groups. Weaning weights and average daily gain of male lambs were higher (P < 0.05) in lambs fed Ca salt (3% and 5%) when compared to 0% treatment group. No differences were detected in weaning weights and average daily gain of female lambs among treatment groups. However, milk conversion ratio was better (P < 0.05) for the 5% group lambs than the 0% and 3% treatment groups. Ca salt reduced (P < 0.05) short and medium-chain milk fatty acids and increased (P < 0.05) content of long chain and unsaturated ones. These results of this indicate that Ca salt supplementation can improve milk production of lactating ewes, the growth rate of their lambs, and produce healthy quality value milk. 相似文献
16.
C.P. Ferris J.P. Frost C.S. Mayne M.A. McCoy D.J. Kilpatrick 《Livestock Science》2008,114(2-3):305-314
Two experiments were undertaken to examine the direct and residual responses of late lactation (mean of 232 days calved) autumn calving dairy cows (Experiment 1), and late lactation (mean of 240 days calved) spring calving dairy cows (Experiment 2), to once-daily milking. Experiments 1 and 2 involved 50 and 44 Holstein–Friesian dairy cows respectively. In each of the two experiments, cows were milked either once daily (ODM) or twice daily (TDM), during the late lactation period (mean of 79 and 66 days in Experiments 1 and 2 respectively). Cows in Experiment 1 were managed within a grazing system, and were offered 3.0 kg of concentrate/day, while cows in Experiment 2 were housed, and offered grass silage supplemented with 6.0 kg concentrate/day. Forty-one cows from Experiment 1, and 32 cows from Experiment 2, completed the first eight weeks of the subsequent lactation on a twice-daily milking regime. Food intakes were not measured in Experiment 1, while treatment had no significant effect on dry matter intake in Experiment 2 (P > 0.05). In each of Experiments 1 and 2, total milk output was increased with twice-daily milking (P ≤ 0.05), while milk fat (P ≤ 0.01) and protein (P < 0.001) concentrations increased with once-daily milking. Somatic cell counts were higher with animals milked once daily in Experiment 1 (P < 0.001), while not being significantly affected by milking frequency in Experiment 2 (P > 0.05). Milking frequency had no significant effect on cow live weight or on cow condition score at the point of drying off in either Experiment (P > 0.05). Milking time per cow during morning milking was unaffected by treatment in either experiment, while total daily milking time per cow (morning and evening combined) was significantly longer with the TDM treatment (P < 0.001). In Experiment 1, milk flow rates during the morning milking were higher with animals on the ODM treatment, compared to those on TDM treatment (P < 0.001), while being unaffected by treatment in Experiment 2 (P > 0.05). Neither daily milk yield, milk fat content, milk protein content, or somatic cell count during the subsequent lactation, were affected by previous lactation milking frequency in either of Experiments 1 or 2 (P > 0.05). 相似文献
17.
This study was conducted to determine the effects of monensin or virginiamycin, or both on the performance of and some energy balance parameters in Holstein cows. Forty multiparous Holstein cows were used in a randomized complete block design experiment. The basal diet was a total mixed ration based on lucerne hay (38% of DM) and ground maize (34% of DM). The experimental treatments were (1) control diet (C); (2) control diet plus 15 ppm of monensin (M); (3) control diet plus 20 ppm of virginiamycin (V), and control plus M (15 ppm) plus V (20 ppm). Cows received 8 kg/d (as fed) of the experimental diets plus ad libitum Eragrostis curvula hay from 3 weeks prepartum and only the experimental diets from calving until 60 days postpartum. Cows were milked twice daily. Dry matter intake did not differ between treatments, but energy corrected milk production was increased (P < 0.10) by supplementing V + M (43.3 kg/d) when compared to treatments M (36.9 kg/d) and V (37.9 kg/d). Change in body weight tended (P = 0.11) to be lower for cows supplemented with V + M (− 8.1 kg/60 d) when compared to cows receiving the control diet (− 34.2 kg/60 d). Both treatments M and V respectively, decreased blood BHBA and treatment M increased blood glucose when compared to the control diet (P < 0.10). Results suggest a complimentary effect between the two additives monensin and virginiamycin when supplemented to early lactation cows. 相似文献
18.
An experiment was performed on 113 heifers born during three successive autumns (1987, 1988, and 1989) and aimed to study the effect of rearing strategy on performances and longevity. From 4–12 mo of age, heifers were grazing (G) or fed indoors with two levels of a corn-silage based diet (CS) with a high (CSH) or low (CSL) level concentrate. Age at first calving was 24 months (AFC24), but, because of seasonal calving management, some animals calved at 36 months of age (AFC36). From 4–12 mo of age, average daily weight gain (ADG) of G, CSL and CSH heifers was 874, 736 and 890 g/d, respectively. G and CSH heifers had the same ADG from 4–12 mo of age, whereas G and CSL heifers had the same ADG from 4 mo of age until puberty. Puberty was detected for 106 heifers, occurring at 269 (SD = ± 28) d of age at a weight of 286 (± 36) kg. On average, CSH heifers were 28 d younger at puberty (P < 0.001). In AFC24 heifers, fertility after one insemination was higher for CS heifers than for G heifers (77 and 55%, respectively). When heifers were adults, it corresponded to 77 and 96%, respectively. During their 1st lactation, AFC24 (G and CSL) heifers tended to have a higher milk peak than CSH heifers (27.3, 28.8 and 24.7 kg/d, respectively). On average, each cow completed 2.64 lactations (range = 0–7), but this parameter varied significantly (P < 0.05): 2.81 (G), 2.67 (CSL), 2.30 (CSH). Productive life was 852 d long, with significant differences between groups (945, 890 and 663 d for G, CSL and CSH groups, respectively). Culling rate during the first four lactations was around 38%. A deleterious effect of an excessive growth rate between 120 and 300 d, corresponding to body weight varying between 150 and 260 kg, was noted. In practice, this indicates that growth rates should be controlled before puberty, but a high growth rate is possible between puberty and first insemination without major problems. 相似文献
19.
This study investigated the effects of dietary δ-aminolevulinic acid (ALA) on growth performance, nutrient digestibility, blood parameters and whether ALA improved the immune response of weanling pigs challenged with Escherichia coli lipopolysaccharide (LPS). Eighty pigs (body weight = 7.21 ± 0.51 kg) were allotted to four dietary treatments, with four pens per treatment and five pigs per pen. Basal diets were supplemented with 0, 5, 10, and 15 mg/kg ALA (as-fed basis) and fed for 35 days. At the end of the feeding period, 10 pigs were selected from both the 0- and 10-mg/kg ALA treatment groups; five were injected i.p. with LPS (50 μg/kg BW) and the other five pigs with an equivalent amount of sterile saline, resulting a 2 × 2 factorial arrangement. Blood sample and rectal temperature data were collected at 0, 2, 4 and 12 h after challenge. Growth performance was not affected by dietary treatments over the total experimental period. However, dry matter (DM) and nitrogen (N) digestibility was improved in the 15-mg/kg ALA treatment group at day 35 (P < 0.05). Serum hemoglobin (Hb) and iron levels were also increased, with the 10-mg/kg ALA treatment showing the highest concentration (P < 0.05). On day 35, red (RBC) and white blood cell (WBC) counts were elevated, with the 5- and 10-mg/kg ALA treatments having the highest counts (P < 0.05). During challenge, LPS injection elevated rectal temperature at 2 and 4 h postchallenge (P < 0.05). Plasma cortisol concentration was also increased by LPS injection at 2 and 4 h postchallenge and an ALA-alleviating effect was evident at 2 h postchallenge (P < 0.01). Concentration of plasma insulin-like growth factor-I (IGF-I) was increased in the ALA-supplemented treatments at 2 h postchallenge (P < 0.05). LPS injection increased plasma tumor necrosis factor-α (TNF-α) concentrations at 2, 4 and 12 h (P < 0.01), while an ALA-alleviating effect was observed at 2 and 4 h postchallenge (P < 0.05 and P < 0.10, respectively). Challenge with LPS decreased WBC counts at 2 and 4 h postchallenge (P < 0.01). At 12 h postchallenge, RBC, WBC and lymphocyte counts were affected by LPS challenge, while an ALA effect was only observed on WBC count (P < 0.05). In conclusion, dietary supplementation of ALA in weanling pigs can improve DM and N digestibilities, and iron status and have a beneficial effect on the immune response during inflammatory challenge. 相似文献
20.
This study determined colostrum production of lactating primiparous and multiparous Holstein dairy cows, as well as the predictability of full lactation milk yield based upon this colostrum production. Holstein cows that calved between December 18, 2006 and December 24, 2007 (n = 134) had their first two post-partum milkings weighed and assayed for density. Cows then entered normal production groups and were assessed for milk yield and milk components every 4 or 5 weeks for the duration of their lactation. Primiparous cows produced less colostrum (10.6 versus 13.6 kg; P = 0.02) and density adjusted (DA) colostrum (5.2 versus 8.5 kg; P < 0.01), but there were no differences in estimated 305 day mature equivalent (305ME) milk production (mean = 13,654 kg) or lactation lengths (mean = 301 days) between parities. Colostrum and DA colostrum were poor estimators of subsequent 305ME milk production within primiparous cows (r2 = 0.20 and 0.01 respectively) and multiparous cows (r2 = 0.18 and 0.12 respectively). Colostrum production of these high producing cows was somewhat lower than expected, highly variable among cows within parity, higher for multiparous versus primiparous cows, and was not a good estimator of subsequent 305ME milk production. 相似文献