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Michael Friend - One of the best experts on this subject based on the ideXlab platform.
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Reduced survival of lambs from maiden Ewes exposed to mature Ewes pre-lambing
Small Ruminant Research, 2017Co-Authors: Susan Robertson, Mb Allworth, Michael FriendAbstract:Abstract The suboptimal survival of new-born lambs is a major source of reproductive inefficiency, is often lower in maiden (first-lambing) compared with multiparous Ewes, and this may be associated with poor maternal behaviour due to inexperience. This study examined whether the survival of lambs from maiden Ewes could be increased by exposing maiden Ewes to multiparous lambing Ewes in the month before lambing. Pregnant maiden Merino Ewes (n = 446) which had been mated at 18 months of age were allocated to three replicates of two treatments. During the month prior to the maidens lambing, control groups were grazed in paddocks each with 30 multiparous mature (5.5 and 6.5 years of age) Merino Ewes which were due to lamb at the same time as the maiden Ewes. The exposed treatment groups also grazed with 30 mature Ewes, during which time the mature Ewes lambed. All mature Ewes and lambs were removed and the groups of maiden Ewes grazed in separate 5.3 ha paddocks from 10 days before the maidens were due to lamb. The survival of lambs to marking age was lower (P = 0.035) from maidens exposed to mature lambing Ewes (0.73) compared with those that grazed only with pregnant mature Ewes (0.81). The number of lambs reared per ewe lambing was not lower (P = 0.274) from the exposed (0.92) compared with the control (0.98) Ewes. This study showed that the survival of lambs from maiden Ewes was reduced by exposing them to mature lambing Ewes, and it is recommended to avoid grazing lambing mature Ewes in the same paddock with maiden Ewes in the month prior to the maiden lambing.
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Survival of lambs from maiden Ewes may not be improved by pre-lambing exposure to mature lambing Ewes
Animal Production Science, 2017Co-Authors: Susan Robertson, Mb Allworth, Michael FriendAbstract:The survival of lambs born to Ewes at their first (maiden) lambing is generally lower than for those born to Ewes which have previously lambed, and poor maternal behaviour is a contributing factor. This study examined whether pre-lambing exposure of maiden Ewes to multiparous lambing Ewes would improve the survival of lambs born to maiden Ewes. Pregnant maiden (n = 333, 2 years of age) Merino Ewes were allocated to three replicates of two treatments: exposed – maidens were grazed with multiparous Merino Ewes (n = 111, 5 or 7 years of age), which were due to lamb during the 2 weeks before the start of maiden lambing, with mature Ewes comprising 50% of the mob size; and non-exposed – maiden Ewes grazed in paddocks without mature Ewes. The total number of Ewes per paddock (74), number of Ewes per hectare (14.0) and paddock size were the same in both treatments. The number of lambs born per ewe was similar between treatments, indicating a similar proportion of multiple births. The proportion survival of lambs from maiden Ewes exposed to adults (0.53) tended to be lower (P = 0.091) than the survival of lambs born to maiden Ewes grazing alone (0.61). The number of lambs marked per ewe lambing was similar (P = 0.284) in exposed (0.71) compared with non-exposed (0.78) maidens. The survival of lambs from maiden Ewes was not improved by lambing in the same paddock with adults, even where the adults had largely completed lambing before the maidens commenced.
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Ewe movement and ewe-lamb contact levels in shelter are greater at higher stocking rates
Animal Production Science, 2012Co-Authors: John Broster, Susan Robertson, David Rathbone, Belinda King, Michael FriendAbstract:This experiment used contact loggers and GPS collars to evaluate the effect of stocking rate during lambing on ewe movement and contact levels between animals. Twin-bearing Merino Ewes were placed in 0.5-ha paddocks sheltered with rows of hessian at stocking rates of 16 and 30 Ewes/ha for the low and high stocking rates, respectively. The Ewes did not spend more time in more sheltered areas of the paddock, and use of shelter was not influenced by stocking rate. Ewes at the high stocking rate travelled 11% farther per day but crossed through the hessian rows 37% less than Ewes at the low stocking rate. Stocking rate did not change the level of contact between Ewes, but higher levels of contact were shown between Ewes and their lambs at the high stocking rate. The results suggest that the interaction between Ewes and their lambs is modified by stocking rate and/or flock size for small groups lambing in shelter rows.
Susan Robertson - One of the best experts on this subject based on the ideXlab platform.
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Reduced survival of lambs from maiden Ewes exposed to mature Ewes pre-lambing
Small Ruminant Research, 2017Co-Authors: Susan Robertson, Mb Allworth, Michael FriendAbstract:Abstract The suboptimal survival of new-born lambs is a major source of reproductive inefficiency, is often lower in maiden (first-lambing) compared with multiparous Ewes, and this may be associated with poor maternal behaviour due to inexperience. This study examined whether the survival of lambs from maiden Ewes could be increased by exposing maiden Ewes to multiparous lambing Ewes in the month before lambing. Pregnant maiden Merino Ewes (n = 446) which had been mated at 18 months of age were allocated to three replicates of two treatments. During the month prior to the maidens lambing, control groups were grazed in paddocks each with 30 multiparous mature (5.5 and 6.5 years of age) Merino Ewes which were due to lamb at the same time as the maiden Ewes. The exposed treatment groups also grazed with 30 mature Ewes, during which time the mature Ewes lambed. All mature Ewes and lambs were removed and the groups of maiden Ewes grazed in separate 5.3 ha paddocks from 10 days before the maidens were due to lamb. The survival of lambs to marking age was lower (P = 0.035) from maidens exposed to mature lambing Ewes (0.73) compared with those that grazed only with pregnant mature Ewes (0.81). The number of lambs reared per ewe lambing was not lower (P = 0.274) from the exposed (0.92) compared with the control (0.98) Ewes. This study showed that the survival of lambs from maiden Ewes was reduced by exposing them to mature lambing Ewes, and it is recommended to avoid grazing lambing mature Ewes in the same paddock with maiden Ewes in the month prior to the maiden lambing.
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Survival of lambs from maiden Ewes may not be improved by pre-lambing exposure to mature lambing Ewes
Animal Production Science, 2017Co-Authors: Susan Robertson, Mb Allworth, Michael FriendAbstract:The survival of lambs born to Ewes at their first (maiden) lambing is generally lower than for those born to Ewes which have previously lambed, and poor maternal behaviour is a contributing factor. This study examined whether pre-lambing exposure of maiden Ewes to multiparous lambing Ewes would improve the survival of lambs born to maiden Ewes. Pregnant maiden (n = 333, 2 years of age) Merino Ewes were allocated to three replicates of two treatments: exposed – maidens were grazed with multiparous Merino Ewes (n = 111, 5 or 7 years of age), which were due to lamb during the 2 weeks before the start of maiden lambing, with mature Ewes comprising 50% of the mob size; and non-exposed – maiden Ewes grazed in paddocks without mature Ewes. The total number of Ewes per paddock (74), number of Ewes per hectare (14.0) and paddock size were the same in both treatments. The number of lambs born per ewe was similar between treatments, indicating a similar proportion of multiple births. The proportion survival of lambs from maiden Ewes exposed to adults (0.53) tended to be lower (P = 0.091) than the survival of lambs born to maiden Ewes grazing alone (0.61). The number of lambs marked per ewe lambing was similar (P = 0.284) in exposed (0.71) compared with non-exposed (0.78) maidens. The survival of lambs from maiden Ewes was not improved by lambing in the same paddock with adults, even where the adults had largely completed lambing before the maidens commenced.
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Ewe movement and ewe-lamb contact levels in shelter are greater at higher stocking rates
Animal Production Science, 2012Co-Authors: John Broster, Susan Robertson, David Rathbone, Belinda King, Michael FriendAbstract:This experiment used contact loggers and GPS collars to evaluate the effect of stocking rate during lambing on ewe movement and contact levels between animals. Twin-bearing Merino Ewes were placed in 0.5-ha paddocks sheltered with rows of hessian at stocking rates of 16 and 30 Ewes/ha for the low and high stocking rates, respectively. The Ewes did not spend more time in more sheltered areas of the paddock, and use of shelter was not influenced by stocking rate. Ewes at the high stocking rate travelled 11% farther per day but crossed through the hessian rows 37% less than Ewes at the low stocking rate. Stocking rate did not change the level of contact between Ewes, but higher levels of contact were shown between Ewes and their lambs at the high stocking rate. The results suggest that the interaction between Ewes and their lambs is modified by stocking rate and/or flock size for small groups lambing in shelter rows.
Rodolfo Ungerfeld - One of the best experts on this subject based on the ideXlab platform.
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Close contact with spontaneously cycling Saint Croix Ewes triggers cyclic activity in seasonally anestrous Suffolk Ewes
Animal Production Science, 2016Co-Authors: Agustín Orihuela, Neftalí Clemente, Rodolfo UngerfeldAbstract:In domestic goats, oestrous activity may be induced by close contact with cyclic females. As tropical breeds of sheep show light seasonality or are even unaffected by season, the purpose of this study was to examine the hypothesis that cyclic activity may be induced in anestrous Suffolk Ewes by close contact with spontaneously cycling Saint Croix Ewes. The experiment was conducted with 17 anestrous Suffolk Ewes that were assigned to one of two groups. Although Suffolk Ewes in the Control group (n = 9) remained isolated, those of the treated group (n = 8) were joined (Day 0) and maintained in close contact with 20 Saint Croix Ewes for 38 days. Serum progesterone concentration was measured in all Ewes in blood samples collected on Days –8, –2, 8, 13, 18, 23, 28, 33 and 38. Before Day 0, 17/20 Saint Croix Ewes were cycling, but no Suffolk ewe had luteal levels of progesterone. By Day 13, more treated than Control Suffolk Ewes had progesterone luteal concentrations (8/8 vs 1/9; P = 0.0004). It was concluded that spontaneously cycling Saint Croix Ewes induce cyclic activity in anestrous Suffolk Ewes.
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Reproductive response in suckling Corriedale Ewes to the ram effect during the non-breeding season: effect of postpartum condition and the use of medroxyprogesterone priming.
Tropical animal health and production, 2006Co-Authors: Leticia Silva, Rodolfo UngerfeldAbstract:The response to the ram effect and the use of progestagen priming was studied in postpartum suckling Corriedale Ewes. Two experiments were carried out during the non-breeding season. In experiment 1, the effectiveness of the ram effect to induce fertile oestrus in postpartum Ewes was determined. While no significant differences in the frequency of Ewes in oestrus were found, the overall conception rate was significantly higher in Ewes that were weaned at least 6 months before the study started (63.3%) than in 60–90 days postpartum Ewes (45.3%, p < 0.01). In experiment 2, the influence of medroxyprogesterone acetate priming on the response to the ram effect in suckling Corriedale Ewes was determined. The frequency of Ewes in oestrus and conception rate between Ewes that remained unprimed and 6-days-primed Ewes were similar. We conclude that it is possible to induce oestrus in postpartum suckling Corriedale Ewes using the ram effect during the non-breeding season and that the use of progestagen priming seems to be ineffective in improving the response of postpartum Ewes to the ram effect.
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response of anestrous Ewes to the ram effect after follicular wave synchronization with a single dose of estradiol 17 beta
Reproduction Nutrition Development, 2004Co-Authors: Rodolfo Ungerfeld, Ana Laura Dago, E Rubianes, M ForsbergAbstract:Anestrous Ewes respond to the introduction of rams with either an ovulation within 2- 3 days that may be followed by luteal phases of normal or short length, with delayed ovulations (5- 6 days later), or with the luteinization of follicles. The aim of this work was to study the relationship between the growth status of the largest follicle present when rams are introduced and the type of ovarian response in non-treated Ewes and in Ewes treated with estradiol-17β before ram introduction. Thirteen anestrous Corriedale Ewes were divided into 2 groups: E2 (n = 7) and C (n = 6). The E2 Ewes received a single dose of 50 µg estradiol-17β 5 days before the introduction of the rams to synchronize the onset of their follicle waves, while C Ewes remained untreated. When the rams were introduced, all E2 Ewes had the largest follicle in a growing stage in contrast with the C Ewes (3 out of 6; P < 0.05). Five C and 4 E2 Ewes ovulated after the introduction of the rams (Day 3.4 ± 0.4 for C vs. 4.8 ± 0.3 for E2 Ewes, respectively, P < 0.05). Only one ewe from each group developed a normal luteal phase; 4 C and 3 E2 Ewes had short luteal phases. One C ewe and 2 E2 Ewes had short luteal phases originating from follicles that did not ovulate. After the first luteal phase, all Ewes returned to anestrus without a second ovulation or luteal phase. The remaining E2 ewe did not ovulate or show any changes in progesterone serum concentrations. We conclude that the growth status of the largest follicle alone does not determine the ovarian responding pattern of anestrous Ewes to the ram effect. follicular dynamics / ultrasound / ram stimulus / ovulation / non-breeding season
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Response of anestrous Ewes to the ram effect after follicular wave synchronization with a single dose of estradiol-17$\beta$
Reproduction Nutrition Development, 2004Co-Authors: Rodolfo Ungerfeld, Ana Laura Dago, E Rubianes, M ForsbergAbstract:Anestrous Ewes respond to the introduction of rams with either an ovulation within 2-3 days that may be followed by luteal phases of normal or short length, with delayed ovulations (5-6 days later), or with the luteinization of follicles. The aim of this work was to study the relationship between the growth status of the largest follicle present when rams are introduced and the type of ovarian response in non-treated Ewes and in Ewes treated with estradiol-17$\beta$ before ram introduction. Thirteen anestrous Corriedale Ewes were divided into 2 groups: E2 (n = 7) and C (n = 6). The E2 Ewes received a single dose of 50 $\mu$g estradiol-17$\beta$ 5 days before the introduction of the rams to synchronize the onset of their follicle waves, while C Ewes remained untreated. When the rams were introduced, all E2 Ewes had the largest follicle in a growing stage in contrast with the C Ewes (3 out of 6; P < 0.05). Five C and 4 E2 Ewes ovulated after the introduction of the rams (Day 3.4 ± 0.4 for C vs. 4.8 ± 0.3 for E2 Ewes, respectively, P < 0.05). Only one ewe from each group developed a normal luteal phase; 4 C and 3 E2 Ewes had short luteal phases. One C ewe and 2 E2 Ewes had short luteal phases originating from follicles that did not ovulate. After the first luteal phase, all Ewes returned to anestrus without a second ovulation or luteal phase. The remaining E2 ewe did not ovulate or show any changes in progesterone serum concentrations. We conclude that the growth status of the largest follicle alone does not determine the ovarian responding pattern of anestrous Ewes to the ram effect.
Francisco G. Véliz-deras - One of the best experts on this subject based on the ideXlab platform.
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Appetitive and Consummatory Sexual Behaviors of Rams Treated with Exogenous Testosterone and Exposed to Anestrus Dorper Ewes: Efficacy of the Male Effect
Archives of Sexual Behavior, 2017Co-Authors: Luz M. Tejada, Cesar A. Meza-herrera, Raymundo Rivas-muñoz, Rafael Rodríguez-martínez, Evaristo Carrillo, Miguel Mellado, Francisco G. Véliz-derasAbstract:We determine whether Dorper rams treated with testosterone in the sexual resting season trigger both appetitive and consummatory sexual behaviors and sexual and reproductive outcomes in anestrous Ewes at 26° North during March–April. Dorper rams ( n = 12, 2.5 years) were randomly divided prior to mating in two groups: GT (treated group; n = 6), treated with testosterone propionate (25 mg i.m. every 3 days × 3 weeks) and GC (control group; n = 6), treated with saline. Thereafter, adult anovulatory Dorper Ewes ( n = 61) were exposed to the GT-rams while the other group ( n = 60) was exposed to the GC-rams. Ram’s appetitive sexual behavior was similar (50 %) in both groups, yet the GT-rams exerted 100 % of the consummatory sexual behavior. Sexual and reproductive outcomes of the anestrus females exposed to both male groups considered two phases: 0–15 and 16–25 days from exposure to males. Involved variables were: Ewes in estrus, Ewes ovulating, duration of estrus, pregnant Ewes, and lambed Ewes. All the average variables favored those Ewes exposed to GT-males: Ewes in estrus: 85 versus 40 %; Ewes ovulating: 80 versus 53 %; duration of estrus: 37 versus 25 h; pregnant Ewes: 60 versus 31 %, and lambed Ewes: 57 versus 31 %. Results confirm that adult Dorper rams treated with exogenous testosterone had improved consummatory sexual behavior and induced increased ovulation and pregnancy rates when exposed to anestrus Ewes. This feasible and inexpensive testosterone-based protocol through the male effect also enhanced both sexual and reproductive outcomes in previously anestrous Dorper Ewes during the natural out-of-season. Results are important to speed up reproductive performance of sheep during the natural anestrous season at this latitude, while also they embrace interesting outcomes from a comparative sexual behavior stand point.
Pierre-guy Marnet - One of the best experts on this subject based on the ideXlab platform.
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Effect of weaning system on milk composition and distribution of milk fat within the udder of east friesian dairy Ewes
Journal of Dairy Science, 2002Co-Authors: B.c. Mckusick, D.l. Thomas, J.e. Romero, Pierre-guy MarnetAbstract:We investigated whether the inhibition of milk ejection during and/or between machine milkings is responsible for the low milk fat observed in commercial milk obtained from dairy Ewes managed with a mixed system (MIX) of partial daily suckling (10 h) and once daily machine milking (after 14 h of udder filling). East Friesian crossbred dairy Ewes were randomly allocated postpartum to the MIX system (n = 9) or to exclusive twice-daily machine milking (DY1, n = 8). Following wk 4, MIX Ewes were permanently weaned from their lambs and milked twice daily. All Ewes were injected with saline, oxytocin, or an oxytocin-receptor antagonist prior to three morning milkings during wk 2, 4, and 6 of lactation to study cisternal and alveolar milk distribution. Overall milk yield (cisternal + alveolar) for MIX Ewes was 42% greater than for DY1 Ewes during wk 2 and 4, which demonstrates the beneficial effect of lamb suckling on milk production of dairy Ewes. However, during normal machine milking, only the cisternal fraction was obtained from MIX Ewes, confirming that milk ejection did not occur for as long as these Ewes remained in partial daily contact with their lambs. Although the volume of milk stored within the cistern, and its concentration of milk protein was similar for the two weaning systems, milk of MIX Ewes was significantly inferior in cisternal milk fat concentration and yield compared to DY1 Ewes. This provides evidence that not only is there inhibition of milk ejection during machine milking of MIX Ewes, there is additional inhibition of transfer of milk fat, but not milk protein, from the alveoli to the cistern during the evening when MIX Ewes are separated from their lambs. Following weaning of MIX Ewes, the majority of lactation traits studied were similar compared to DY1 Ewes.
