Vitamin and trace element supplementation in grazing dairy ewe during the dry season: effect on milk yield,composition, and clotting aptitude

A study was carried out to evaluate the influence of vitamin and trace mineral supplementation on milk production and composition in grazing dairy ewes during the dry season. Ewes (n = 50) were assigned at weaning to blocks and treatments. Ewes were daily conducted (8 h/day) on a pasture based on Italian ryegrass (Lolium multiflorum). At fold, ewes received a basal diet composed by ad libitum oat hay and a definite amount of a pelleted concentrate. Dietary treatments included: (1) the control concentrate containing background of vitamin and trace mineral only, and (2) the experimental concentrate containing the premix supplement (10 g/kg of dry matter). Vitamin and trace mineral supplementation did not affect ewes’ body weight. Milk, fat- and protein-corrected milk, fat percentage, and clotting properties were improved in ewes fed supplemented concentrate. There was a week × treatment interaction (P < 0.05) for yield of milk and corrected milk that was greatest at peak production in ewes fed the premix. Our findings indicate that in grazing dairy ewe, the dietary vitamin and trace mineral supplementation during dry season led to an increase of milk production and quality, with positive improvement in milk clotting aptitude.     

Comparative study between sheep and goats on rumenic acid and vaccenic acid in milk fat under the same dietary treatments

A number of studies have shown that the rumenic acid (RA = cis-9 trans-11 C_18:2 CLA) content of milk fat is usually higher in sheep than in goats, due partly to different dietary regimens. An experiment was conducted with 12 lactating dairy ewes and 12 goats with the objective to compare the two animal species (sheep/goats) fed diet with the same forage/concentrate (F/C) ratio, on their milk fatty acids (FA) profile with emphasis on RA and vaccenic acid (VA) production. The experiment was carried out in three consecutive phases, lasted 3 weeks each, immediately after weaning of lambs and kids. In phase I, the ewes and the goats were fed according to their maintenance and lactation requirements, with 14 kg alfalfa hay, 4 kg wheat straw and 12 kg concentrate the 12 ewes (F/C ratio = 60/40), and with 14 kg alfalfa hay, 4 kg straw and 24 kg concentrate the 12 goats (F/C ratio = 43/57). In phase II, 14 kg alfalfa hay, 4 kg straw and 14 kg concentrate were offered daily to each group of sheep and goats, with a F/C ratio = 56/44. In phase III, all ewes and goats were fed individually with 0.8 kg alfalfa hay, 0.2 kg wheat straw and 0.8 kg concentrate daily with a F/C ratio = 56/44. The results showed that the different F/C ratio between sheep and goats diets, in phase I, changed significantly the milk FA profile, with no significant difference in RA and VA milk fat content between sheep and goats in phase I. In phases II (group feeding) and III (individual feeding), where sheep and goats fed with the same amount of food of the same F/C ratio, the sheep milk fat had higher RA and VA content compared to goats. In conclusion, these findings support the hypothesis that there are species differences, as RA and VA production concerns, which needs further investigation.     

Herbage intake and milk yield in Comisana ewes as effect of 4 vs 7 h of grazing during late lactation

Thirty-two Comisana ewes at late lactation were used in two trials carried out during late spring in 2 consecutive years, with the aim to evaluate the effect of the duration of grazing on herbage intake and performance. In each trial, 16 pluriparous Comisana lactating ewes were equally divided into two groups which grazed in two separate areas of natural pasture from 11:00 to 15:00 h (group 4H) or from 10:00 to 17:00 (group 7H). A concentrate mixture (500 g/day) was also offered to each ewe. The mean maximum temperature was, respectively, 23.5 ± 3.8 °C during experiment 1 and 27.0 ± 3.1 °C during experiment 2. Probably as a consequence of the differences in climatic conditions, the results on herbage intake and milk production were different during the two trials. Herbage dry matter intake was not affected by the duration of grazing during trial 1, whereas it was significantly lower in 4H group compared to that in 7H group (0.67 vs 1.02 kg/day; P < 0.001) during trial 2. It could be hypothesised that while with lower environmental temperature (trial 1), the 4H ewes were able to reach good intake levels despite grazing during the hottest hours; with higher temperatures throughout the trial (trial 2), the 4H ewes reduced ingestion. Milk production was higher in 4H group during trial 1 (778 vs 707 g/day; P = 0.006), whereas it was not affected by the number of hours of grazing during trial 2, despite the higher intake levels reached by the 7H group. In conclusion, 3 extra hours of grazing for ewes at late lactation on a low quality pasture could be nullified in terms of yield response.     

Effects of Ca salt supplementation on milk yield and composition and on lamb growth rate of Awassi ewes

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.     

Reproductive performance of seasonal ewes and does fed dry fat during their postpartum period

This study was carried out to evaluate the effect of feeding a dry fat source to seasonal ewes and does on their postpartum reproductive performance. Forty five multiparous Awassi ewes (LW = 60.1 ± 3.2 kg) and 45 Shami does (LW = 49.6 ± 2.4 kg) were randomly assigned into 3 dietary treatments (n = 15/spp) for 60 days postpartum in a completely randomized design (CRD) set. Females were housed with their offsprings and fed one of three isonitrogenous total mixed rations (TMR) containing 0, 3, or 5% of dry fat. Blood samples were taken individually every 3 days to determine serum progesterone concentration levels starting one week postparturition via radioimmunoassay kits. Progesterone concentrations increased (P < 0.05) in ewes fed 3% fat addition but not for 5% level. Meanwhile, those of doe were not affected by adding supplemental fat. No differences were observed in days to 1st or 2nd postpartum ovulation in both species. Milk production was higher (P < 0.05) for fat treated ewes with no differences between the 2 fat levels, while it was not different among does groups. Final live weight of females in both species was also not affected by fat supplementation. However, live weight changes were higher (P < 0.05) for ewes with no differences between 3% fat level and control groups, and lower in does with increased fat level and with no differences between the 2 treatment groups. Weaning weight and average daily gain of the newborn in both species were not affected by fat supplementation. Litter weight was not different for ewes, but it was higher (P < 0.05) for treated does with no differences between 3% and 5% supplemented fat groups. Therefore, one can conclude that supplemental fat to ewes at 3% during their postpartum period might recover their cyclicity late in the breeding season, but not at high levels (5%), and can improve their milk production and affect live weight change during that period with no effect on weaning weight or litter weight of lambs. For does, supplemental fat is not capable of affecting their postpartum cyclicity, milk production, and weaning weight of their kids, but reduces their live weight change and litter weight.     

Milk fatty acid profile from cows fed with mixed rations and different access time to pastureland during early lactation

Milk fatty acid (FA) profiles were determined in Holstein cows (n = 27) fed total mixed rations (TMR) ad libitum (G0) or diet composed by TMR (50% dry matter [DM] offered) plus grazing of pasture with 6 hr of access time to paddock in one session (G1) or 9 hr in two sessions (G2) at 45 days in milk (DIM). Moreover, milk FA was determined at 65 DIM when G0 cows turned out to G1 diet without adaptation period (Post‐G0), G1 remained as controls. Milk FA was quantified using gas chromatography and mass spectrometry. Preformed FA at 45 DIM was greater (+27%) for G2 than G0 cows (p < .05). Stearic acid (C18:0) was 30% greater for G2 cows (p < .05). De novo FA was lowest for G2 cows (p < .05). Conjugated linoleic acid (CLA) did not differ (p < .12), while vaccenic acid (C18:1trans) was twofold greater for grazing treatments (p < .01). Linolenic acid [C18:3(n‐3)] was greatest for G2 and lowest for G0 cows (p < .01). Omega 6 FA was greater for G0 than grazing cows, mainly due to linoleic acid [18:2cis(n‐6); p < .05]. These results determined that n‐6/n‐3 ratio was almost threefold greater for G0 than grazing cows (p < .001). When diet of G0 cows changed to include pasture (Post‐G0), preformed FA increased (p < .05), explained mainly by the increase (p < .05) of stearic (C18:0) and C18:1trans, while de novo FA tended to decrease (p < .1). Moreover, the amount of CLA and C18:3(n‐3) tended to increase (p < .1) in Post‐G0 cows. Offering 50% of dietary DM from pasture modified milk FA profile in early lactation potentially beneficial for human health. When TMR‐fed cows were turned out to 50% pasture, milk FA profile reflected dietary change without need of an adaptation period.     

Influence of the calf presence during milking on dairy performance,milk fatty acid composition,lipolysis and cheese composition in Salers cows during winter and grazing seasons

The milking of Salers cows requires the presence of the calf. The removal of the calf would simplify the milking routine, but it could also modify the milk yield and the milk and cheese composition. Therefore, the aim of this experiment was to evaluate the effect of calf presence during milking during sampling period (winter or grazing periods), on dairy performance, milk fatty acid (FA) composition, lipolysis and cheese yield and composition. Nine and 8 Salers lactating cows were milked in the presence (CP) or absence (CA) of their calves respectively. During winter, the cows were fed a hay‐based diet and then they only grazed a grassland pasture. Calf presence during milking increased milk yield and milk 16:0 concentration and decreased milk fat content and milk total odd‐ and branched‐chain FA (OBCFA) concentrations. Calf presence only increased initial lipolysis in milk collected during the winter season. Milk from CP cows compared to CA cows resulted in a lower cheese yield and ripened cheeses with lower fat content. Milk from the grazing season had lower saturated medium‐chain FA and OBCFA concentrations and higher 18:0, cis‐9‐18:1, trans‐11‐18:1 and cis‐9, trans‐11‐CLA concentrations than that from the winter season. Initial milk lipolysis was higher in the winter than in the grazing season. These variations could be due to seasonal changes in the basal diet. Furthermore, the effect of calf presence during milking on milk fat composition was lower than that on dairy performance, cheese yield and composition. Removing the calf during the milking of Salers cows seems feasible without a decrease in milked milk, and with a positive effect on cheese yield and fat content, under the condition that we are able to select cows having the capacity to be milked easily without the calf.     

Discrimination of “grazing milk” using milk fatty acid profile in the grassland dairy area in Hokkaido

Milk produced by the grazing system, referred to as “grazing milk” contains many components required for human health. The milk fatty acid (FA) profile is strongly associated with the diet on the farms. In the present study, based on the FA profile of farmer's bulk milk, we determined how to discriminate between milk produced on grazing and on a confinement system. A field survey was conducted four times (grazing and confinement season) in the Konsen (29 farms) and Okhotsk (25 farms) area in Hokkaido. Farmer's bulk milk samples and details of feeding management were collected and the FA profile of milk was measured. Milk produced during the grazing season contained less C16:0 and cis‐9 C16:0, and more C18:0, cis‐9 C18:1, trans‐11 C18:1, cis‐9,12 C18:2, cis‐9,trans‐11 C18:2 and cis‐9,12,15 C18:3 than milk produced during the confinement season. Discrimination analysis using 16 FA revealed that almost all milk samples were discriminated correctly (confinement season: 90% correct and 10% borderline, grazing season: 88% correct, 9% borderline and 3% incorrect). For farmers that were categorized incorrectly and were considered borderline in the grazing season, the dependency on pasture was low compared with that for farmers correctly discriminated. Therefore, to claim “grazing milk”, a high dependency on pasture is required for grazing dairy farmers.     

Milk production responses to pre- and postcalving dry matter intake in grazing dairy cows

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.     

Performance and grazing behaviour of Churra Tensina sheep stocked under different management systems during lactation on Spanish mountain pastures

Thirty-six adult ewes rearing single male lambs were randomly allocated to three paddocks (n = 12) grazing permanent Pyrenean pastures in spring (0.5 ha/lot). Treatments were rationed grazing (Rat-Gr) in which lambs remained indoors and ewes grazed during 8 h/day (08:00–16:00 h) and were supplemented 0.5 kg/day of barley meal; continuously grazing ewes rearing non-supplemented lambs (Gr) and continuously grazing ewes rearing supplemented lambs in creep feeders at pasture (Gr + S). Grazing behaviour was registered at weekly intervals by direct observation during the outdoor time in Rat-Gr and from dawn to dusk in Gr and Gr + S.

Sward height of Rat-Gr became higher than the rest (P < 0.05), resulting in a greater dry matter and a lower crude protein content of this pasture (P < 0.05). Ewe live-weight, body condition score and lumbar fat thickness were similar across treatments (P > 0.05), while milk yield was higher in Gr + S (P < 0.05). Lambs from Rat-Gr and Gr + S presented a higher average daily gain than Gr treatment (P < 0.05). Grazing behaviour records showed that all treatments spent grazing similar percentages of daylight time at pasture (average 52%; P > 0.05). Ewes biting rate was greater in Gr (P < 0.05) and it was higher after noon in all treatments (P < 0.001). Gr and Gr + S showed an extended peak of grazing (min/h) in the evening. Lambs followed the grazing pattern of dams since 3 weeks old. It was concluded that in contrast with the traditional indoor system of managing production of light lambs both spring continuous grazing systems allowed producing Ternasco lambs (18–24 kg LW, younger than 90 days old). Lambs supplemented suckling their mothers and grazing until slaughter showed similar performance to those obtained in indoor system. Dietary supplementation of lambs at pasture did not impair ewes milk yield and grazing time but reduced their biting rate and the offspring grazing time.     

The effect of high calcium intake by pregnant Awassi ewes at late gestation on minerals status and performance of ewes and newborn lambs

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.     

农牧交错带人工草地放牧对奶牛生产性能的影响

研究不同放牧制度和强度对在“多年生禾草+紫花苜蓿(Medicago sativa)”人工草地上放牧奶牛的采食量、产奶量、乳成分及体重和体况分的影响。结果表明:轮牧制奶牛的采食量低于连续放牧制,中度放牧低于轻度放牧。轻度轮牧有较高的体增重和较小的体况分损失,连续放牧则相反。轮牧制奶牛的产奶量显著高于连续放牧制,中牧高于轻牧。不同放牧处理对乳成分的影响不显著,轻度轮牧的乳脂率低于中度轮牧和连续放牧,轻度轮牧的乳蛋白最高,乳糖和乳干物质含量则无显著变化。     

The effects of allowance and frequency of allocation of autumn-saved pasture, when offered to spring lambing ewes in mid pregnancy, on ewe and lamb performance and subsequent herbage yield

The effects of (i) frequency of herbage allocation and (ii) herbage allowance on ewe and subsequent lamb performance, when autumn-saved (extended grazed, deferred grazed) pasture is grazed (between 28 Nov and 30 Jan) by spring lambing ewes during mid gestation, were studied in Experiment 1. This involved 72 crossbred ewes from days 41 to 104 of gestation allocated to one of four treatments; two herbage dry matter (DM) allowances (1.0 and 1.8 kg per ewe) by two frequencies of herbage allocation (daily or twice weekly). From day 105 of gestation to parturition all ewes were housed and offered grass silage (ad libitum) plus a total of 19 kg concentrate. Increasing herbage allowance improved ewe body condition score (P < 0.01) and live weight (P < 0.01) at the end of deferred grazing, and tended to increase herbage intake (P = 0.08) during deferred grazing. Reducing the frequency of herbage allocation increased lamb birth weight (P < 0.05). Otherwise frequency of herbage allocation did not alter (P > 0.05) forage intake or utilization, or ewe or subsequent lamb performance. In Experiment 2, the effects of herbage allowance (1.0 or 1.8 kg DM per ewe), frequency of allocation (daily, twice weekly) and grazing date (28 Nov. to 4 Dec., 12 to 18 Dec., 2 to 8 Jan. and 23 to 29 Jan.) during deferred grazing on herbage yield and composition at four subsequent harvest dates (4, 18 and 25 Apr., and 25 May) were evaluated in a split-plot design consisting of 128 plots. Delaying grazing date reduced herbage yield (P < 0.05) and the concentrations of neutral detergent fibre (NDF; P < 0.01) and acid detergent fibre (ADF; P < 0.01). Delaying harvest date increased herbage yield (P < 0.001) and reduced (P < 0.001) the concentrations of NDF, ADF and metabolisable energy. Increasing herbage allowance at grazing increased (P < 0.05) subsequent herbage yield. Frequency of herbage allocation during deferred grazing did not affect (P > 0.05) subsequent herbage yield. There was a significant interaction (P < 0.001) between grazing date and harvest date for herbage yield. It is concluded that to maximise stock carrying capacity and reduce labour requirement a herbage DM allowance of 1 kg per ewe per day, allocated twice weekly, is sufficient for ewes on deferred grazed pasture in mid pregnancy.     

Responses to condensed tannins of flowering sulla (Hedysarum coronarium L.) grazed by dairy sheep: Part 2: Effects on milk fatty acid profile

A grazing experiment was undertaken to evaluate the effect of PEG supplementation on the fatty acid composition of milk from Sarda sheep grazing sulla. Twenty-four late-lactating sheep (12 per group), were paired and split into two groups: group control (CON), dosed daily with a quenching gun with 200 ml of water, and group PEG, dosed with 200 ml of a 50/50 w/v water solution of PEG. The sheep grazed two 0.8 ha plots of sulla under a rotational grazing scheme.The contents of c-9, t-11 CLA and t-11 C18:1 in milk fat were on average 40% higher (P < 0.01) in the PEG group than in the CON group. This can be explained by the higher biohydrogenation activity of ruminal bacteria in the PEG group, due to the partial inactivation of the tannins. Odd-branched chain fatty acids (OBCFA) were higher in PEG than in the control group (+ 20%; P < 0.01) and this confirms the hypothesis that tannin in sulla reduced ruminal microbial activity. Both linoleic (C18:2 c-9 c-12) and linolenic (C18:3 c-9 c-12 c-15) fatty acids were lower (P < 0.05) in milk from PEG, than in the CON-group (− 12% and − 30% for linoleic and linolenic acids, respectively). The mitigating effect on tannins of PEG increased the ratio of ω6/ω3 by 24%; (P < 0.01) and total trans FA content in milk by 20% (P < 0.01). In conclusion, condensed tannins in sulla at flowering are conducive to lower c-9, t-11 CLA and t-11 C18:1 but also lower total trans FA, ω6/ω3 ratio and higher linoleic and linolenic acid.     

Milk production and fatty acid profile of dairy cows grazing four grass species pastures during the rainy season in small-scale dairy systems in the highlands of Mexico

The study evaluated small-scale dairy systems with continuous grazing of pastures based on three temperate grasses festulolium (FL), tall fescue (TF), and perennial ryegrass (RG), compared with subtropical kikuyu grass (KG). All pastures were associated with white clover (Trifolium repens L.). Twelve multiparous Holstein cows were assigned to a 4?×?4 Latin square replicated three times with 14-day experimental periods. Sampling and analyses of pastures, concentrates, and animal variables followed standard procedures. FL showed a significantly (p?<?0.05) higher mean sward height, but there were no differences (p?>?0.05) in net herbage accumulation. There were significant differences (p?<?0.05) among pastures for CP, NDF, ADF, in vitro digestibility of OM (IVOMD), and estimated metabolizable energy (eME). There were no differences (p?>?0.05) between treatments for milk yield and composition, live weight, or body condition score. There were significant differences (p?<?0.05) in fatty acid values for pastures in C14:0, C16:1, and C18:3n3. There were significant differences between treatments (p?<?0.05) in milk contents for C18:0, C18:1t11, and C18:2c9t11. Grazing FL, TF, RG, or KY pastures showed no differences in milk yields. Higher values for C18:0, C18:1t11, and C18:2c9t11 were detected in KY, RG, and TF. RG had significantly higher MUFA than FL and higher PUFA than TF. A value under 65% of SFA, a ratio of n-6/n-3 lower than 4, and an atherogenic index of 1.7 are indicators of milk with beneficial effects for human health.     

Influence of percentage of concentrate in combination with rolled canola seeds on performance, rumen fermentation and milk fatty acid composition in dairy goats

The effect of rolled canola seeds (RCS, 0% or 20% of the dry matter (DM) of the concentrate) combined with percentage of concentrate (45% (L) vs. 65% (H) of the diet DM) on rumen fermentation characteristics, production parameters and fatty acid (FA) profile of milk fat was studied in 20 entire goats and 12 goats fitted with ruminal and duodenal cannula. Goats were fed TMR ad libitum for 15 weeks with the final 12 weeks as the test period. Individual milk samples were taken in weeks 5 and 11 to determine the FA profile of milk fat. Feeding the H diets increased NE_L intake, raw milk yield and yield of fat, protein and lactose. Feeding RCS increased fat corrected milk, milk fat content and fat yield. Combination of RCS and high percentage of concentrate increased fat corrected milk and fat yield. Milk protein content was not affected by dietary factors. Feeding the H diets increased the proportion of short-chain FA (C4:0–C8:0), each isomer of trans-C18:1 and c9,t11-C18:2 in milk at the expense of medium-chain FA with 11 to 17 C units. Feeding RCS decreased the proportion of medium-chain FA with 10 to 17 C units in milk and it increased that of C18:0, all isomers of trans-C18:1, c9-C18:1 and c9,t11-C18:2. Goats fed the H diets, and those fed the RCS had lower c9-C18:1/C18:0 and c9,t11-C18:2/t11-C18:1 ratios. Combination of RCS and high percentage of concentrate produced the highest proportion of all isomers of trans-C18:1 and c9,t11-C18:2 in milk, with the highest variability among the four diets for these FA. This was possibly related to between-goats differences in ruminal fermentation and to individual difference in desaturase activity in the mammary gland. It is concluded that feeding a high-concentrate diet combined with rolled canola seeds had a synergistic effect on the milk production and fat yield without alteration in milk protein content in dairy goats. This combination also resulted in changes in FA profile that may differently affect the nutritional value of goat milk for human health.     

Behavioral, adrenal, immune, and productive responses of lactating ewes to regrouping and relocation.

The experiment involved 40 mid-lactating Comisana ewes. The animals were housed in straw-bedded pens and assigned to a control group (n = 10) and two test groups of 15 subjects each. Control ewes were never moved from their pen and peers throughout the experiment period, whereas test animals were subjected to either regrouping (RG) or regrouping and relocation (RGRL) three times at weekly intervals (d 7, 14, and 21 of the trial). Three behavioral recordings were conducted after each social and pen exchange over a 6-h period (1000 to 1600). Animals from groups RG and RGRL were bled immediately before each regrouping and relocation and 15 and 60 min afterward. The phytohemagglutinin skin test was performed at d 9, 16, and 23. Milk yield was recorded when the ewes were mixed and moved, and before and after each mixing and moving procedure. Individual milk samples were analyzed for composition, renneting parameters, and bacteriological characteristics; samples with more than 10(6) somatic cells/mL were cultured for mastitis-related pathogens. Control ewes spent more time lying than groups RG (P < 0.001) and RGRL (P < 0.01) and less time in ambulatory activities than RGRL sheep (P < 0.05). Moved and remaining ewes showed a higher number of aggressive interactions than control subjects (P < 0.001 and P < 0.01, respectively). Control sheep showed the highest cell-mediated immune response compared with both moved and mixed ewes (P < 0.001 and P < 0.01, respectively). The RGRL ewes gave lower yields of milk than did the control ewes on the days after the first (P < 0.05) and the second (P < 0.01) change of pen and peers. The RGRL ewes also had a lower fat content (P < 0.05) than control ewes in the milk yielded on the day of the first regrouping and relocation and a lower milk protein content (P < 0.05) on the following day. The RG treatment resulted in the ewes yielding milk with a lower fat content (P < 0.01) on the day of each mixing procedure as compared with controls and in a decreased milk protein content on the days after the first (P < 0.05) and the second regrouping (P < 0.01). One case of subclinical mastitis was recorded in both the RG and RGRL groups, whereas no cases were detected in control group. These findings suggest that regrouping and relocation may cause increased aggression, altered immune responses, and short-term effects on the production performance of lactating ewes. These practices should be performed by attempting to minimize their impact on animal welfare.     

Evaluating the effect of calcium,magnesium and sodium supplementation of Merino ewes on their lambs' growth

Our study aimed to investigate responses to supplementation of calcium (Ca), magnesium (Mg) and sodium (Na) to lactating ewes and lambs grazing barley forage from lamb marking to weaning. A 10-ha paddock sown to barley was subdivided into eight plots as four replicates of two treatments. Merino ewes (n = 104) with lambs at foot were stratified to the eight plots (13 ewes and 21 lambs/plot) based on number of lambs (twin or single) and ewes' weight. Supplemented groups had access to mineral supplements (30 g/ewe/day) supplying 12 g/ewe/day ground limestone, 12 g/ewe/day Causmag® and 6 g/ewe/day coarse salt in a ratio of 2: 2: 1 by weight (as fed) from day 0 (a day before lamb marking) after sample collection. Control groups were not supplemented with minerals. Blood, milk and urine samples from ewes and blood from lambs were collected at different time points, namely, a day prior to lamb marking (day 0), 14 days after the commencement of study (day 14), and 28 days after the commencement of study (day 28). Weight of the lambs was also recorded at each time point. We found that the concentration of the forage minerals (Ca, Mg and potassium (K)) was lower on day 28 than on day 0 (P < 0.025). Liveweight gain was greater in the first 14 days compared with the second weight gain period (P < 0.001). The interaction of time and treatment was significant for liveweight (P < 0.001). Due to the improvement in weight gain of supplemented lambs, we recommend that mineral supplementation during late lactation is beneficial considering the low cost of minerals, even though the mineral content of the forage was not deficient.     

Dairy cow defecation and urination frequency and spatial distribution in relation to time-limited grazing

The objective of this paper was to investigate the effect of limited grazing time on urination and defecation frequency, spatial distribution of excrement in the paddock, and the resulting nitrogen balance at animal and field level. During a 6-week period in early summer, 60 Holstein Frisian dairy cows (31.0 ± 5.4 kg ECM) were randomly allocated to three different treatments, with grazing at clover-grass pasture during daytime for 4, 6.5 or 9 h daily. Indoor feeding, with a mixture of roughage and concentrates (13% crude protein), was restricted for treatment 4 and 6.5 h to the amount the 9-h treatment could eat. Cows allowed grazing at pasture for 4 h moved more rapidly during pasture, moved longer distance per active hour and used a higher proportion of the time eating, both at pasture and indoor, than the cows allowed longer time at pasture. Limiting the grazing time had no influence on the urination (mean = 0.26) and defecation (mean = 0.37) frequency per cow per hour during pasture. Even though the proportion of time active (eating, drinking, standing or walking), and the actual time active during pasture was different for the treatments, the frequency of urination and defecation per active hour was also unaffected by the treatments. Urine and faeces were distributed in the pasture, without specific hot-spots. The estimated daily N-balance at animal level showed increased N excretion with time at pasture. Assuming that excretion follows the active periods during the day and 7000 kg DM foliage is available on yearly basis, this would result in total excretion at field level of 58, 86 and 108 kg N per ha respectively for treatment 4, 6.5 and 9 h. The results of this experiment show that it is possible to reduce the nitrogen excretion in a grazing system by restricting the grazing time of dairy cows together with restricted indoor feeding while maintaining high foliage intake.