Effects of supplementing fish oil in the drinking water of dairy cows on production performance and milk fatty acid composition

The objective of this study was to determine the effects of supplementing fish oil (FO) in the drinking water of dairy cows on production performance and milk fatty acid composition. Sixteen multiparous Holstein dairy cows (741 +/- 84 kg of BW; 60 +/- 2.3 d in milk, mean +/- SD) housed in a tie-stall facility were used in the study. The study was conducted as a completely randomized design with repeated measurements. The cows were blocked by days in milk and allocated to 1 of 2 treatments: 10 g of menhaden FO/kg of DM top-dressed on the total mixed ration (FOT), and 2 g of menhaden FO/L delivered in the drinking water (FOW). The trial lasted for 5 wk: a 1-wk pretreatment adjustment period and 4 wk of treatment. The animals were fed and milked twice daily (feeding at 0830 and 1300; milking at 0500 and 1500) and had unlimited access to water. Dry matter intake (21.3 kg/d for FOT vs. 22.7 +/- 0.74 kg/d for FOW), milk yield (38.2 kg/d for FOT vs. 39.5 +/- 1.9 kg/d for FOW), and water intake (101 L/d for FOT vs. 107 +/- 4.4 L/d for FOW) were not affected by treatment. The mode of delivery of FO had no effect on milk fat percentage, but milk fat percentage declined linearly with time. The fatty acid contents of 7:0; 8:0; 9:0; 10:0; 12:0 in the milk of FOT cows were lower than for FOW cows, whereas 18:1 trans-12; 18:1 trans-13 and 14; 18:1 trans-16; and trans-9, trans-11 plus trans-10, trans-12 CLA were greater for FOT than for FOW. The contents of 24:1 in the milk of FOW cows were 48% greater than for FOT cows, although the concentrations were low in both groups. There was a tendency for the contents of 14:0 and 22:5n-6 to be greater in FOW cows than FOT cows and for the contents of iso-18:0 to be lower for FOW cows than for FOT cows. Although it appears that the amount of FO added in the study did not bypass the rumen as hypothesized, these results suggest that drinking water can be an alternative for supplementing FO to dairy cows without decreasing feed or water intake relative to cows fed FO in the diet.     

Feed handling of lactating crossbred cows maintained in a semi‐arid region during the hot season: physiological parameters,ingestive behavior and performance

The effects of time of feed delivery (14.00 hours; 14.00 and 20.00 hours; 16.00 and 18.00 hours) on the physiological parameters, ingestive behavior, nutrient intake and production of lactating cows maintained in a semi‐arid region during the hot season were evaluated. Regardless of treatment, all animals received the first feeding supply at 06.00 hours. Eight cows with an average body weight of 600 kg, average milk yield of 20 kg/day and 80 days in milk were utilized. The rectal temperature, respiratory rate and sweating rate were not affected (P > 0.05), with average values of 38.5°C, 53.8 movements/min and 104 g/m²/h respectively. There was no effect (P > 0.05) on the eating time (314 min/day), ruminating time (564 min/day), drinking time (61 min/day) and idle time (502 min/day). Similarly, the intake of nutrients and performance of lactating cows were not affected (P > 0.05), with average dry matter intake of 19.8 kg/day, 4% fat‐corrected milk of 20.6 kg/day and milk fat concentration of 4.03 g/100 g. Since the behavior and performance have not altered, any times of feed delivery evaluated could be used to crossbred Holstein × Zebu cows maintained on a feedlot in semi‐arid regions during the hot season.     

Effect of feeding sorghum ergot (Claviceps africana) to sows during mid‐lactation on plasma prolactin and litter performance

Diets containing 3% sorghum ergot (16 mg alkaloids/kg, including 14 mg dihydroergosine/kg) were fed to 12 sows from 14 days post‐farrowing until weaning 14 days later, and their performance was compared with that of 10 control sows. Ergot‐fed sows displayed a smaller weight loss during lactation of 24 kg/head vs. 29 kg/head in control sows (p > 0.05) despite feed consumption being less (61 kg/head total feed intake vs. 73 kg/head by control sows; p < 0.05). Ergot‐fed sows had poorer weight gain of litters over the 14‐day period (16.6 kg/litter vs. 28.3 kg/litter for controls; p < 0.05) despite an increase in consumption of creep feed by the piglets from the ergot‐fed sows (1.9 kg/litter compared with 1.1 kg/litter by the control; p > 0.05). Sow plasma prolactin was reduced with ergot feeding after 7 days to 4.8 μg/l compared with 15.1 μg/l in the control sows (p < 0.01) and then at weaning was 4.9 μg/l compared with 8.0 μg/l (p < 0.01) in the control sows. Two sows fed ergot ceased lactation early, and the above sow feed intakes, body weight losses with litter weight gains and creep consumption indirectly indicate an ergot effect on milk production.     

The effect of protein-feeding strategy during lactation on performance of primiparous dairy cows fed total mixed ration

Fifty primiparous Finnish Ayrshire cows were used in 2×2 factorial study. The factors were the protein-feeding strategy: constant (cCP) or variable (vCP) protein content in concentrate during lactation and the use of a commercial health product from 2 weeks pre- to 8 weeks postpartum. On treatment cCP, the CP content of the concentrate was 180 g/kg in dry matter (DM) throughout the lactation, and on vCP treatment, the CP content was 210, 180 and 150 g/kg DM during lactation days 0-100, 101-200 and 201-305, respectively. The concentrate blends included barley, oats, rapeseed meal, molassed sugar beet pulp and minerals and vitamins. Grass silage and ensiled wet sugar beet pulp (100 g/kg DM in TMR) were used as forage. The forage-to-concentrate ratio in TMR was 55:45 on both treatments. The experimental period was 305 days of the first lactation.The average daily milk yield (cCP: 26.3 kg/day vs. vCP: 27.5 kg/day) was higher (P<0.05) when feeding concentrate with decreasing protein content, but the effect was not seen in an energy-corrected milk (cCP: 28.1 kg/day vs. vCP: 29.0 kg/day). Milk composition was not affected by the protein-feeding strategy. Protein-feeding strategy had no effect on DM intake (cCP: 18.5 kg/day vs. vCP: 18.9 kg/day). The efficiency of CP utilization (milk protein/CP intake) was higher (0.327 vs. 0.301; P<0.05) on vCP treatment during the last 100 days of lactation, but during the first 200 days of lactation, no significant difference was found. The average efficiency of CP utilization throughout the lactation was 0.32 with no difference between treatments. The protein-feeding strategy had no effect on the development of body condition scores of the cows. In mid-lactation, the cows on cCP treatment gained more weight than the cows on vCP treatment. The health product had no significant effect on production or feed intake. The results suggest that only small benefits can be obtained from feeding TMR to primiparous cows differing in CP content at various stages of lactation.     

Effects of feeding and animal performance on nitrogen, phosphorus and potassium excretion by Holstein cows

Thirty‐four Holstein dry cows and 16 lactating cows were used in balance trials to identify the effects of feeding and animal performance on nitrogen (N), phosphorus (P) and potassium (K) excretion by dairy cows, and to develop prediction models for these excreta. Orchard grass silage, corn silage, alfalfa silage or timothy hay were offered to dry cows. Orchard grass silage or alfalfa silage, and concentrates were offered to lactating cows. In the statistical analysis, the independent variables were bodyweight (kg), dry matter (DM) intake (kg/day), milk yield (for lactating cows only, kg/day), water intake (free water plus water in feed, kg/day), intake (g/day) of N, P and K and dietary contents (% of DM) of crude protein, P and K. The dependent variables were N, P and K excretion (g/day) in feces and urine. In both dry and lactating cows, intake of N, P and K had large effects on corresponding excretion. The results indicated that a decrease in the intake of N, P and K could decrease the corresponding excretion. Further research by path analysis showed that K intake positively affected urinary N excretion in dry cows indirectly, through water intake and urine volume.     

Oats (Avena strigosa) as winter forage for dairy cows in Vietnam: an on-farm study

In North Vietnam, during winter, alternative forage resources are needed to balance the feed ration of dairy cows. The objective of this study was to investigate the effect of oat forage as a component of traditional winter roughage diets on feed intake, milk production and feeding cost in dairy cows. The study was conducted on-farm using 24 mid-lactation Holstein–Friesian cows. The feeding experiment consisted of two successive periods and two dietary treatments per period. Traditional basal diets included fresh tropical grasses, maize silage and hay. The oat forage had no effect on the dry matter intake of the basal diet, but the total crude protein intake was higher in cows fed with oat diets than in those fed with control diets. The yield of butterfat-corrected milk (FCM) was not significantly different between diets during period 1, but there was a trend (P?=?0.078) of higher FCM yields in cows fed with the oat diet compared to those with control diet during period 2 (17.3 vs. 16.3 kg/day). The decline rate in milk yield was significantly higher (P?<?0.001) in cows fed with control diets than in those fed with oat diets in both experimental periods. The total feeding cost of cows fed with oat diets was on average 12 % lower than those fed with control diets (P?<?0.01). So, the oat forage is an important winter resource for cows in North Vietnam allowing higher milk yield whilst reducing feeding cost, compared to traditional roughage diets.     

Estimation of Milk Production from Smallholder Dairy Cattle in the Coastal Lowlands of Kenya

A study was carried out on 92 smallholder farms in Kwale district in Coast Province of Kenya to estimate the milk yield. The effect of concentrate feed supplementation on milk yield was also evaluated. Data were collected during a one-year observational longitudinal study. Analysis was done for 371 observations following 63 calving events. The mean annual milk offtake was estimated at 2021 kg/cow. Forty-nine (77.8%) of the lactating cows were supplemented with concentrate feeds at varying rates of 0.5-3.0 kg/cow per day. Supplementary feeding of lactating cows led to a significantly higher mean daily milk yield compared to non-supplemented cows throughout the year (p < 0.05). The mean annual milk offtake from supplemented cows (2195 kg/cow) was 18.6% more than offtake from non-supplemented cows, a difference that was statistically significant (p < 0.05). Therefore, supplementary feeding of commercial feed concentrates was a rational management practice. It was also concluded that milk production from smallholder dairy cows in the coastal lowlands of Kenya was comparable to that from similar production systems but lower than national targets.     

Effect of diet on preweaning performance of Sahiwal calves

The objective was to study the growth potential of Sahiwal calves given milk or milk replacer with or without concentrates. For this purpose, forty-eight Sahiwal calves were divided into four groups of 12 animals each with equal sex ratio. In each group, the calves were offered either milk or a milk replacer (MR) at a rate of 10% of their body weight adjusted weekly. In addition to this, calves were fed either a starter ration plus Egyptian clover hay (SR + H) or hay only (H) until the end of trial. The milk or MR was withdrawn gradually from day 56 until animals were weaned completely by day 84. Calves offered milk grew faster than those offered MR (357 ± 9 vs. 162 ± 9 g/day; p < 0.05) and displayed higher weaning weights (51.6 ± 0.8 vs. 35.2 ± 0.8 kg; p < 0.05). The calves offered SR + H grew faster (311 ± 9 vs. 208 ± 9 g/day; p < 0.05) and displayed higher weaning weights (48.7 ± 0.8 vs. 38.1 ± 0.8 kg; p < 0.05) than those fed H alone. Calves offered milk plus SR + H showed the highest growth rate and weaning weights (401 ± 13 g/day and 56.3 ± 1 kg, respectively). The lowest growth rate and weaning weights were observed in calves offered MR and H only (115 ± 13 g/day and 30.3 ± 1 kg, respectively). Calves offered the MR had higher number of scour days than those offered milk (13.5 vs. 3.3). The feeding of whole milk in combination with the starter ration and hay resulted in superior growth rates, higher weaning weights, and healthier calves than the other feeding regimens.     

Effect of feeding Bacillus subtilis natto fermentation product on milk production and composition, blood metabolites and rumen fermentation in early lactation dairy cows

This experiment was conducted to determine the effect of Bacillus subtilis natto fermentation product supplementation on blood metabolites, rumen fermentation and milk production and composition in early lactation dairy cows. Thirty-six multiparous Holstein cows (DIM = 29 ± 6 days, parity = 2.8 ± 1.1) were blocked by DIM and parity and then randomly assigned to three treatments (12 per treatment) in a 9-week trial. Cows in control, DFM1 and DFM2 were fed TMR diets supplemented with 0, 6 and 12 g of B. subtilis natto solid-state fermentation product per day per cow respectively. Plasma non-esterified fatty acids were lower (p = 0.03) in DFM1 and DFM2 compared with control cows (633 and 639 vs. 685 μm). Ruminal propionate increased (23.9 vs. 26.3 and 26.9/100 mol, control vs. DFM1 and DFM2 respectively) and acetate decreased (64.2 vs. 62.7 and 62.1/100 mol, control vs. DFM1 and DFM2 respectively) with increasing B. subtilis natto fermentation product supplementation. DMI of the cows in three treatments was not affected by B. subtilis natto fermentation product supplementation, but milk yield was 3.1 and 3.2 kg/day higher for DFM1 and DFM2 than that for control cows on average across the 9-week trial, and significant differences were observed during weeks 5-9 of the trial, which resulted in 9.5% and 11.7% increase in feed efficiency. B. subtilis natto fermentation product supplementation did not affect milk fat percentage and protein yield but increased (p < 0.05) milk fat yield and lactose percentage (p < 0.01) and tended to decrease protein percentage (p = 0.06). The findings show that B. subtilis natto fermentation product was effective in increasing lactation performance of early lactation dairy cows possibly by altering the rumen fermentation pattern without any negative effects on blood metabolites.     

Relationship between feeding behaviour and feed intake of dairy cows depending on their parity and milk yield

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.     

Does body size of dairy cows,at constant ratio of maintenance to production requirements,affect productivity in a pasture‐based production system?

This study compared productivity of dairy cows with different body weight (BW), but a constant ratio of maintenance to production requirements in their first lactation, in a pasture-based production system with spring calving. Two herds, Herd L (13 and 14 large cows in 2003 and 2004 respectively; average BW after calving, 721 kg) and Herd S (16 small cows in both years; 606 kg) [Correction added after online publication 14 January 2011: 16 small cows in both years; 621 kg was changed to 16 small cows in both years; 606 kg], all in their second or following lactations, were each allocated 6 ha of pasture and rotationally grazed on 10 parallel paddocks with equal herbage offer and nutritional values. Winter hay, harvested from the same pastures, was offered ad libitum in the indoor periods in a tied stall barn. Each herd received, per lactation and year, approximately 2000 kg dry matter (DM) of concentrates and of fodder beets, equally distributed to every individual. Indoors, the L-cows ingested more DM than the S-cows (18.7 vs. 16.3 kg DM/cow per day; p < 0.01), but DM intake per 100 kg of metabolic BW was similar (13.0 vs. 13.1 kg DM/cow per day). Estimates based on the n-alkane technique gave similar results on pasture (17.9 vs. 15.5 kg DM/cow per day; p < 0.001). Roughage intakes per 100 kg of metabolic BW, at 13.5 kg DM/cow per day, were similar. Mean annual yield of energy-corrected milk (ECM)/ha was slightly higher for the S-herd than the L-herd (13,026 vs. 12,284 kg) but was associated with a higher stocking rate (on average +20%) for the S-herd. Feed conversion efficiency (1.2 vs. 1.3 kg ECM/kg DM intake) and overall milk production efficiency (45.3 vs. 47.3 kg ECM/kg metabolic BW) were similar in L- and S-cows. Thus, both dairy cow types were equally efficient in utilising pasture-based forage.     

Effect of several doses of zeolite A on feed intake,energy metabolism and on mineral metabolism in dairy cows around calving

The object of the present study was to determine the influence of different zeolite A doses on dry matter intake (DMI) and mineral metabolism, and to evaluate an optimum dosage for preventing hypocalcaemia. Eighty pregnant dry cows were assigned to four groups (I–IV). They were fed a total mixed ration (TMR) ad libitum. Groups II, III and IV received an average daily dose of 12, 23 and 43 g zeolite A/kg DM for the last 2 weeks prepartum. Individually DMI was recorded daily. Blood and urine samples were taken before, during and after zeolite A supplementation. Serum was analysed for Ca, Mg, P_i, K, non‐esterified fatty acids and β‐hydroxybutyrate (BHB). Urine was analysed for Ca, Mg, P_i, K and net acid‐base excretion (NABE). After calving, milk yield (fat corrected milk) and milk composition were determined. During zeolite A supplementation, mean DMI of Group IV (7.3 ± 1.3 kg/cow/day) was significantly lower compared to Groups I–III (10.1, 10.9, 9.5 kg/cow/day). The reduced feed intake of Group IV resulted in significantly increased BHB as well as decreased NABE after calving. Zeolite A supplementation in higher doses (III and IV) had a stabilizing effect on Ca metabolism around calving for older cows, whereas cows in Groups I and II showed a subclinical hypocalcaemia. The mean serum Mg concentration decreased significantly in older cows in Group IV at calving. The mean P_i concentration in cows of Group IV decreased into ranges of hypophosphataemia already 1 week after beginning of zeolite A feeding. The mean DMI postpartum as well as the milk yield was not affected by zeolite A supplementation. Feeding of 23 g zeolite A/kg DM TMR prepartum proved to be an adequate dosage for reducing subclinical hypocalcaemia frequency without significant effects on feed intake and P_i concentration in serum.     

Effects of two levels of feed allocation on IGF‐I concentrations and metabolic parameters in GnRH‐immunized boars

Immunocastration of boars leads to a maintenance of growth harmone (GH) and a loss of anabolic hormones [androgens, oestrogens, insulin‐like growth factor (IGF‐I)] but an increase of voluntary feed intake. The aim of the experiment was to clarify whether IGF‐I is increased by increasing feed supply in immunocastrated boars leading to improved anabolism. Two groups of six boars were given 2 or 3 kg of feed (13.5 MJ ME/kg) daily from 18–28 weeks of age. Because in boars feed intake is limited by gonadal hormones, a group with further increased feed supply could not be included. Until week 22 (second vaccination) gonadal steroids in blood were normal but dropped rapidly thereafter. Growth harmone levels did not change following vaccination. Pigs allocated 3 kg feed had 28% higher circulating IGF‐I after the second immunization compared with pigs fed 2 kg feed daily. Higher IGF‐I was associated with increased weight gain (682.4 g/day vs. 466.7 g/day; p < 0.01) and protein synthesis (¹³C‐leucine infusion; 405 g/day vs. 247 g/day, p < 0.01). Protein breakdown (urea) was not different. Body fat (D₂O) decreased in the low feed group from 15.2% (week 19) to 6.1% (week 25). In the high feed group it remained at the level found before second vaccination (13.7% vs. 15.0%). It is concluded that in the phase of reduced testicular steroids which inhibit appetite it is possible to increase feed intake which in turn increases IGF‐I and protein deposition without accumulating excessive fat.     

"特高"黑麦草饲喂泌乳牛试验

“特高”为四倍体一年生黑麦草，1998年从百绿集团引进。通过15d的奶牛饲喂试验，结果表明：在相同的精饲料供给条件下，日饲喂特高黑麦草(50kg／头)的奶牛日产奶2．4kg，比日饲喂青贮玉米(30kg／头) 野杂草(15kg／头)的奶牛高o．4kg，而每公斤牛奶的饲喂成本却降低了0．17元，效益显著。另外，试验中还发现，饲喂黑麦草特高能有效地减少奶牛乳房炎等病症。     

Allocation of feed based on individual dairy cow live weight changes: II: Effect on milk production

Based on individual cow live weight gain, feeding strategies were designed for individual feeding of dairy cows in loose-housing systems, and examined in a four-year production trial including 115 Danish Red (DR), 91 Danish Holstein (DH), and 93 Danish Jersey (DJ). The objective of the present paper was to examine the milk yield obtained in response to three feeding strategies. The interrelationship between feed intake and live weight changes is presented in a companion paper.Cows were stalled in a loose-housing system based on automatic milking, automatic recording of feed intake and automatic weighing of the cows. All cows had 3 kg of individually separately offered concentrate (ISC) in addition to a mixed ration (MR). Cows were either allowed a medium energy MR during whole lactation (strategy MR1) or a high energy MR during early lactation, which was reduced to a low energy MR either early or late (strategy MR2-E and MR2-L). The early and late changes were defined as a live weight gain after live weight minimum at 15 and 35 kg, respectively, for DR/DH and 11 and 25 kg, respectively, for DJ. When MR energy concentration was changed, cows on the MR2 strategies were offered 3 kg per day of extra concentrate. The total allowance of 6 kg ISC was stepwise reduced to 3 kg per day as live weight continued to increase until 50 and 35 kg for DR/DH and DJ, respectively.Compared to feeding the MR1 strategy, the analysis showed that feeding the MR2 strategies did not significantly affect milk yield within primiparous DR and DH or within any DJ, as total lactation feed energy intake within these groups of cows was not significantly affected by the feeding strategy. Results obtained for multiparous DH showed that it is possible to increase milk yield without reducing the milk:feed ratio, when MR2 strategies were applied compared to the MR1 strategy. Feeding high energy rations during early lactation caused a higher peak feed energy intake within multiparous cows of DH and DR, but only multiparous DH obtained higher peak ECM yield in response to higher feed energy intake in early lactation. Across breed the results suggested that cows offered the MR2-E strategy might obtain higher lactation ECM yield compared to cows offered the MR2-L strategy due to a higher ECM yield persistency obtained by cows offered the MR2-E strategy. Results on feed intake and live weight changes presented in a companion paper indicated, that cows offered the MR2 strategies obtained a lower extent of mobilization compared to cows offered the MR1 strategy, and feeding the MR2-E strategy significantly increased duration of the mobilization period, which might have increased MR2-E cows' ability to maintain a high milk production during mid lactation.     

Effect of a peri-parturient eprinomectin treatment of dairy cows on milk production

AIM: To quantify and economically evaluate the effect on milk production of peri-parturient treatment of dairy cows with eprinomectin. METHODS: On 3 farms in separate geographic areas of New Zealand, 849 first-calf heifers and multiparous cows were ranked and paired within parity, date of calving and expected milk production. Within pairs, cows were randomly allocated to treatment with either a commercial formulation of eprinomectin, applied at a dose rate of 500 mug/kg liveweight, or an equivalent volume of vehicle containing no antiparasitic agent and administered at the same dose volume, generally within the first week post-calving. On each farm, trial cows shared the same pasture. Over a single lactation, records were maintained of milk quantity and content. RESULTS: Trichostrongylid eggs were identified in pre-treatment faecal samples from all farms, verifying the presence of gastrointestinal parasites. Overall 25.5% of the cows sampled were positive for nematode eggs, but only 8% had counts 50 eggs per gram of faeces (epg). Daily milk volume, milk protein and milksolids (yield of milk fat + milk protein) were higher for eprinomectin-treated multiparous cows than for controls (milk volume: 20.36 l/day vs 19.76 l/day, p=0.005; milk protein: 0.700 kg/day vs 0.685 kg/day, p=0.012; milksolids: 1.613 kg/day vs 1.583 kg/day, p=0.031, respectively). The daily value of the increased production from eprinomectin-treated multiparous cows was estimated to be NZ0.034 dollar for milk fat (p=0.095) and NZ0.078 dollar for milk protein (p=0.012), equating to NZ0.104 dollars for milksolids (p=0.031), averaged over the whole lactation. No significant difference in milk production was detected between treated and control first-calf heifers. Averaged over the whole herd, the peri-parturient treatment of multiparous cows and first-calf heifers with eprinomectin increased daily milk volume and milk protein production of treated vs control cows (19.28 l/day vs 18.86 l/day, p=0.020, and 0.661 kg/day vs 0.650 kg/day, p=0.047, respectively). CONCLUSION: These data provide evidence that the use of a peri-parturient treatment of eprinomectin on multiparous cows can increase their production of fluid milk and milksolids.     

A novel nutritional strategy to prevent milk fever and stimulate milk production in dairy cows

AIMS: To assess the efficacy of a feed supplement designed to reduce the dietary availability of calcium when fed during the last 2-3 weeks of pregnancy, on the incidence of postparturient hypocalcaemia (milk fever) and on milksolids (MS) production in pasture-fed dairy cows in early lactation. METHODS: In Experiment 1, late-pregnant Holstein/Friesian cows, 4-10 years old, grazing pasture, were either fed the supplement (1 kg/cow/day) for 2-4 weeks prior to calving (n=11) or no supplement (n=10). Plasma calcium concentrations were measured immediately before and after a 20 h fast intended to induce hypocalcaemia at the end of this period, 1-7 days before the cows calved. In Experiment 2, mixed-breed dairy cows, 3-10 years old in 7 commercial dairy herds were fed the same supplement (1 kg/cow/day) for 1-3 weeks immediately prior to calving (n=565) or no supplement (n=614), and incidences of clinical milk fever and MS production at 6-9 weeks post calving were compared between groups. RESULTS: In Experiment 1, plasma calcium concentrations were higher (p=0.01) in supplemented than in non-supplemented cows after fasting, indicating reduced susceptibility to fasting-induced hypocalcaemia. In Experiment 2, the incidence of milk fever was lower (6.4% vs 17.1%, p=0.001) and MS production was higher (p=0.01) in supplemented than in non-supplemented cows. CONCLUSIONS: These preliminary results demonstrate that feeding a supplement designed to reduce dietary calcium availability for 2-4 weeks immediately prior to calving reduced the susceptibility of cows to fasting-induced hypocalcaemia, reduced the incidence of clinical milk fever and increased MS production in early lactation. CLINICAL RELEVANCE: The concept and product reported here have potential to provide dairy farmers with a practical means to prevent hypocalcaemia and improve milk production during early lactation.     

Performance of tropical dairy cows fed whole crop rice silage with varying levels of concentrate

The objective of this experiment was to evaluate the effect of concentrate/milk yield ratios on feed intake, nutrient digestibility, rumen fermentation efficiency, and milk production in dairy cows fed with a basal diet of whole crop rice silage (WCRS). Sixteen crossbred cows (75 % Holstein-Friesian (HF) and 25 % Thai cows) in mid-lactation were assigned to four dietary treatments in a completely randomized design. Treatments corresponding to four concentrate/milk yield ratios (0, 1:1, 1:2, and 1:3 (kg/kg)) were used. All cows were offered WCRS (with 1.5 % urea and 3 % molasses) ad libitum. Silage and concentrate were fed individually twice a day. Results revealed that dry matter intake (12.8–14.5 kg/day), nutrient digestibility (62.5–68.7 %), and rumen fermentation efficiency were not significantly affected by concentrate supplementation. Milk yield (10.2–11.5 kg/day) and milk composition were similar between cows fed with sole WCRS and those supplemented with concentrate mixture, although milk fat tended to increase in cows fed with sole WCRS. In conclusion, sole WCRS fed to dairy cows without concentrate supplementation resulted in similar feed intake, nutrient digestibility, rumen fermentation, and milk production as compared to those supplemented with concentrate in lactating dairy cows. These results suggest that in tropical areas where rice crop is surplus, WCRS could sustain reasonable levels of milk production among dairy cows with little or no concentrate supplementation provided that urea and molasses are included in the silage.     

The effect of monensin Na on the protein content of cow's milk and further performance criteria

In two feeding experiments with 10 dairy cows each the effect of 200 mg monensin Na per animal and day in rations either rich in roughage or in concentrate was studied. In principle, the reactions caused by monensin supplement did not differ between the two types of rations. Monensin supplements resulted in a slight reduction of feed intake, a significantly lower milk fat content and, as a tendency, also a lower milk protein, particularly casein, content and a diminished amount of fat corrected milk (FCM). The pattern of fatty acids in the rumen was shifted in favour of propionic acid and the live weight gain of the cows was higher in the monensin group. There were no improvements with regard to the expenditure of feed and energy per kg FCM.     

Influence of zeolite A supplementation during the dry period of dairy cows on feed intake, on the macro and trace element metabolism around calving and milk yield in the following lactation

The object of the present study was to determine the influence of zeolite A, a calcium binder from the group of the aluminosilicate, on feed intake, macro and trace element metabolism as well as the milk yield in the following lactation in dairy cows. 46 cows were allotted to 2 groups (A--control group and B--experimental group). They were fed a total mixed ration (TMR) ad libitum 2 weeks before calving. Additionally the cows in group B received 90 g zeolite A/kg dry matter (DM). The individually feed intake was registered daily. The serum was analysed for Ca, Mg, and Pi (inorganic phosphate), Fe, FFA (free fatty acid) and beta-HB (hydroxybutyrate) and the plasma for the trace elements Cu, Zn, and Mn. After calving the milk yield (FCM) and the milk composition (fat, protein, lactose and urea) were analysed. Feed intake of group B, amounting to 6.2 +/- 1.3 kg DM/d was around 48% lower as compared to 12.0 +/- 1.4 kg DM/d for group A. The zeolite addition into the TMR showed a stabilizing effect on the average Ca concentration in the serum around calving. This effect led to a significantly lower Mg concentration on the day of calving and 1 day post partum. The Pi concentration was significantly lower already after the 1st week of zeolite supplementation and on the day of calving as compared to group A. There was no essential effect of zeolite A on the trace element concentration. The depression of feed intake for group B led to a significant increase of FFA one week after beginning zeolite supplementation and of beta-HB around calving. The feed intake post partum as well as the milk yield were not affected by zeolite supplementation. Because decreased feed intake of group B after zeolite supplementation and the occurred hypophosphatemia, it is not acceptable to use zeolite A in the proved dose for preventing milk fever.