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The current study investigated the effects of growing ewe lambs to a heavier live weight at breeding on their subsequent reproductive performance and live weight at two and three years of age, and ...

Ewe lamb live weight at first mating (7 months of age) is positively associated with reproductive performance and led to the recommendation of a minimum mating live weight of 40 kg. This experiment...

This study investigated potential carry-over effects of increased growth rates prior to breeding at seven months of age on mammary glands of two-year-old ewes bearing one or two lambs, and examined the association between ewe mammary structures and the growth of their progeny. Ewe live weight and mammary ultrasound measures were recorded at 119 days of pregnancy, 29 days of lactation (L29), and weaning of the progeny (L79) in 64 two-year-old ewes selected from two treatments. The heavy group (n = 32) was preferentially fed prior to their first breeding at seven months of age, achieving an average live weight of 47.9 ± 0.38 kg. The control group (n = 32) weighed an average of 44.9 ± 0.49 kg at breeding. Lambs (n = 74) were weighed at birth, L29 and L79. Udder ultrasound measures did not differ (p &gt, 0.10) between treatments, indicating no carry-over effects of treatments on mammary glands of two-year-old ewes. The association between ultrasound measures and lamb growth seemed to differ depending on lamb birth rank. More research is needed to further investigate these associations and determine whether ultrasonography could be used to identify ewes whose progeny would have greater growth rates based on birth rank.

Monitoring activity patterns of animals offers the opportunity to assess individual health and welfare in support of precision livestock farming. The purpose of this study was to use a triaxial accelerometer sensor to determine the diel activity of sheep on pasture. Six Perendale ewe lambs, each fitted with a neck collar mounting a triaxial accelerometer, were filmed during targeted periods of sheep activities: grazing, lying, walking, and standing. The corresponding acceleration data were fitted using a Random Forest algorithm to classify activity (=classifier). This classifier was then applied to accelerometer data from an additional 10 ewe lambs to determine their activity budgets. Each of these was fitted with a neck collar mounting an accelerometer as well as two additional accelerometers placed on a head halter and a body harness over the shoulders of the animal. These were monitored continuously for three days. A classification accuracy of 89.6% was achieved for the grazing, walking and resting activities (i.e., a new class combining lying and standing activity). Triaxial accelerometer data showed that sheep spent 64% (95% CI 55% to 74%) of daylight time grazing, with grazing at night reduced to 14% (95% CI 8% to 20%). Similar activity budgets were achieved from the halter mounted sensors, but not those on a body harness. These results are consistent with previous studies directly observing daily activity of pasture-based sheep and can be applied in a variety of contexts to investigate animal health and welfare metrics e.g., to better understand the impact that young sheep can suffer when carrying even modest burdens of parasitic nematodes.

Aims: To examine a range of udder and teat traits in Romney ewes and to describe the frequency with which different scores occur, and to investigate associations between lamb survival to weaning an...

Aims: To investigate associations between lamb growth to weaning and dam udder and teat scores measured at pre-mating, pre-lambing, docking and weaning.Methods: Mature Romney ewes (n = 1,009) were ...

Simple Summary Mammary internal structures were associated with milk yield in mature dairy ewes and lamb growth in ewe lambs. This experiment was designed to examine the association between mammary ultrasound measurements and milk yield in ewe lambs and the accuracy of using mammary ultrasound measurements to predict single lamb growth rates to weaning. Mammary internal structures were measured in 45 single-bearing ewe lambs at day 110 of pregnancy, week three (W3), five (W5), and seven (W7) of lactation and at weaning (L69). The ewe lambs were milked once at W3, W5 and W7 and the single lambs were weighed at birth, W3, W5, W7, and L69. The predictions of milk yield were moderate, and the predictions of lamb growth were high to moderate, indicating that mammary ultrasound was more accurate in predicting lamb growth than milk yield. Further investigations are required to identify better indicators of milk yield in ewe lambs. Abstract Mammary cistern size was positively correlated with milk yield of mature dairy ewes, but the association in ewe lambs is unknown. This experiment aimed to examine the associations between mammary ultrasound measurements and the milk yield of ewe lambs at one year of age and to determine the accuracy of using maternal mammary ultrasound to predict single lamb growth rates. Single-bearing ewe lambs (n = 45) were randomly selected and 30 were milked once at weeks three (W3), five (W5), and seven (W7) of lactation. Mammary ultrasound scans were performed at day 110 of pregnancy, W3, W5, W7, and weaning (L69). Single lambs (n = 30) were weighed at birth and at each mammary scanning event. Udder measurements explained 26.8%, 21.4%, and 38.4% of the variation in milk yield at W3, W5 and W7, respectively, and 63.5% and 36.4% of the variation in single lamb growth to W3 and to L69. This ultrasound technique was more accurate in predicting single lamb growth to W3 than milk yield and may enable the identification of pregnant ewe lambs whose progeny would have greater growth rates. More research is needed to identify accurate indicators of superior milk yield and determine whether ultrasound could be used to select ewe lambs.

The experiment aimed to examine the impacts of an increased growth rate of ewes between three and seven months of age on udder development using ultrasound and to establish whether ultrasonography could be used to identify ewe mammary structures that may be indirect indicators of singleton growth to weaning. Udder dimensions, depths of gland cistern (GC), parenchyma (PAR) and fat pad (FP) were measured in late pregnancy (P107), early lactation (L29), and at weaning (L100) in 59 single-bearing yearling ewes selected from two treatments. The ‘heavy’ group (n = 31) was preferentially fed prior to breeding achieving an average breeding live-weight of 47.9 ± 0.38 kg at seven months of age. The ‘control’ group (n = 28) had an average breeding live-weight of 44.9 ± 0.49 kg. Udder dimensions, GC, PAR and FP did not differ between treatments. Lamb growth to L100 was positively associated (p &lt, 0.05) with PAR at P107 and GC at L29. There was no evidence of negative effects of the live-weight gain treatments on udder development of yearling ewes as measured by ultrasonography. The results suggest that this ultrasound method has the potential to identify pregnant yearling ewes which would wean heavier singletons.

Currently, 30–43% of New Zealand sheep farmers breed their ewe lambs, but few retain the offspring as replacements for their flock. No difference in lamb production as a yearling among singletons and twins born to ewe lambs and twins born to mature ewes has been reported, provided the ewe lambs had reached the 60–65% of their likely mature weight prior to breeding at seven to eight months of age. The aim of this experiment was to determine the lamb production from singletons and twins born to ewe lambs and twins born to mature ewes during their first two years of lambing. The experiment included 8-month-old ewes born as twins to mature ewes (M2, n = 135), singletons born to ewe lambs (L1, n = 135), and twins born to ewe lambs (L2, n = 88), bred during the same period to the same rams, over two years. The efficiency of lamb production (total litter weight at weaning divided by the pre-breeding weight of the ewe, for all ewes presented for breeding) after two years of production was not significantly different (p &gt, 0.05) among the groups (0.40 ± 0.02, 0.39 ± 0.02, and 0.39 ± 0.03, for M2, L1, and L2, respectively).

Twin sets of lambs were randomly allocated to one of six treatments: (1) lambs born and managed on ryegrass&ndash, clover-based pasture until conventional weaning approximately at 99 days of age (Grass&ndash, GrassCW), (2) lambs born on ryegrass&ndash, clover-based pasture and early weaned onto a herb&ndash, clover mix at ~45 days of age (Grass&ndash, HerbEW), (3) lambs born on ryegrass&ndash, clover-based pasture, transferred with their dam onto a herb&ndash, clover mix at ~45 days of age until conventional weaning (Grass&ndash, HerbCW), (4) lambs born on ryegrass&ndash, clover mix at ~15 days of age and early weaned onto a herb&ndash, HerbD15EW), (5) lambs born and managed on herb&ndash, clover mix until conventional weaning (Herb&ndash, (6) lambs born on herb&ndash, clover mix and weaned early onto a herb&ndash, clover mix at ~45 days of age (Herb&ndash, HerbEW). In both years, Herb&ndash, HerbCW lambs had greater (p &lt, 0.05) growth rates than lambs in other treatments. The liveweight gains and rumen papillae development of Herb&ndash, HerbEW, Grass&ndash, HerbD15EW and Grass&ndash, HerbEW lambs did not differ (p &gt, 0.05). The weight of the empty digestive tract components at either early weaning or conventional weaning did not differ (p &gt, 0.05) between treatments. Exposing early-weaned lambs to the herb mix for a prolonged period, prior to early weaning, does not improve their subsequent growth.

Liveweight gain of lambs weaned early at a minimum live weight of 14 kg, at ~50 days of age, onto a herb-clover mix was compared with lambs that remained unweaned on a grass-predominant pasture or a herb-clover mix until conventional weaning (at ~99 days of age). Over two years, twin sets of lambs that had a minimum live weight of 14 kg were randomly allocated to one of three treatments: (1) Early weaning of lambs onto a herb-clover mix (HerbEW), (2) ewes and lambs grazing a herb-clover mix until conventional weaning (HerbCW), and (3) ewes and lambs grazing a grass-predominant pasture until conventional weaning (GrassCW). HerbEW lambs had slower (p &lt, 0.05) growth rates than GrassCW lambs between early weaning and conventional weaning in 2016 and were 800 g lighter (p &lt, 0.05) at conventional weaning. In 2017, however, both HerbEW and GrassCW had similar (p &gt, 0.05) growth rates and did not differ (p &gt, 0.05) in live weight at conventional weaning. HerbCW lambs had a greater (p &lt, 0.05) growth rates than both HerbEW and GrassCW lambs in both years. Lambs weaned early onto a herb-clover mix have the potential to achieve live weights similar to lambs unweaned on grass-predominant pasture. Further research, however, is required to understand conditions under which early-weaned lambs can achieve similar live weights.

The use of alternative herbage types such as herb-clover mixes and lucerne can improve the weaning weight of twin and triplet lambs born to mature ewes and single lambs born to ewe hoggets. The aim...

Objective Triplet-born lambs are less likely to survive to weaning than twin-born or single-born lambs. Appropriate ewe-lamb bonding behaviours and lamb vigour behaviours are necessary for survival of lambs. The aim of this experiment was to determine whether maternal nutrition during late pregnancy influenced behaviour of the ewe and her lambs soon after birth, and to determine whether mid-pregnancy body condition score (BCS) influenced any behavioural response. Methods The experiments included ewes that were in BCS 2.0, 2.5, or 3.0 in mid-pregnancy and were fed either ad libitum or to pregnancy-maintenance requirements in late-pregnancy (day 115 until 136 in experiment one, and day 128 until 141 in experiment two). The time taken for lambs to stand, contact dam, suck from dam and follow dam was recorded three to 18 h after birth. The number of high- and low-pitched bleats emitted by the ewe and lambs was recorded, along with maternal behaviour score (MBS) of the ewe. Lambs in experiment two underwent a maternal-recognition test at 12 or 24 h. Results There were significant effects of feeding treatment on bleating behaviour of ewes and lambs, but these were inconsistent among BCS groups and between experiments. Lamb vigour behaviours were not affected by feeding treatment. In experiment one, there was no effect of feeding treatment or BCS on MBS, but in experiment two, ewes in BCS3 in mid-pregnancy had greater MBS than ewes in BCS2 in mid-pregnancy (MBS 3.1/5 vs MBS 2.1/5; p Conclusion Given there were no repeatable effects on behaviour of ewes and lambs, ad libitum feeding rather than feeding for pregnancy-maintenance requirements cannot be used to improve behaviours soon after birth of triplet-bearing ewes in BCS 2-3 and their lambs in extensive pastoral conditions.

This experiment investigated the feasibility of using herb-clover mixes to enable early weaning of lambs at ∼60 days of age. Over two years, twin lambs weighing more than 16 kg were allocated to th...

Lamb growth to weaning has important implications for the profitability of farms producing lambs for meat. Alternative forage crops such as chicory, plantain, red clover and white clover have the potential to increase lamb growth rates to weaning percentage sold to slaughter at weaning. A study was conducted over two years to examine the growth of single-born lambs offered either pasture or herb-mix (chicory, plantain, white clover and red clover) from birth to weaning. Each year, 80 single-bearing ewes were allocated to either a pasture or herb-clover mix. In 2014, ewes and lambs that were offered the herb-clover mix had greater live weights at weaning than those grazed on ryegrass pasture. In 2015, however, no differences in lamb weaning weight was observed. In both years of the study, lambs reared on the herb clover mix had growth rates in excess of 400 g/day, from birth to weaning.

Made available in DSpace on 2018-11-26T15:44:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-06-01 International Sheep Research Centre and Massey University National Research Centre for Growth and Development Over a three year period the performance of lambs being finished on three sward treatments were compared. The three treatments included (i) 'Grass-clover mixture'; perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens) (ii) 'Plantain-clover mixture'; plantain (Plantago lanceolata), white clover and red clover (Trifolium pratense) (iii) 'Chicory-plantain-clover mixture'; plantain, chicory (Cichorium intybus L.), white- and red-clover. Each year was divided into five grazing periods namely; winter, early spring, late-spring, summer and autumn with only the Grass-clover mixture being utilised in the winter due to the growth profile and management requirements of the herb species. Over the three year period, a total of 3353 kg live weight per ha was produced on the Grass-clover mixture, which was less (P < 0.05) than the 3838 kg/ha produced with the Plantain-clover mixture or 3768 kg/ha on the Chicory-plantain-clover mixture. Similarly over the three year period, 1270 kg of carcass weight gain per ha was produced on the Grass-clover mixture, which was less (P < 0.05) than the 1706 kg/ha produced with the Plantain-clover mixture or 1732 kg/ha with the Chicory plantain-clover. This indicates that farmers aimed at lamb finishing can have some confidence that when utilising these herb-clovers mixtures they can increase lamb and meat productivity for at least three years. Massey Univ, Int Sheep Res Ctr, Inst Vet Anim & Biomed Sci, Private Bag 11-222, Palmerston North 4442, New Zealand Sao Paulo State Univ, Dept Anim Sci, Sao Paulo, Brazil Coconut Res Inst, Bandirippuwa Estate, Lunuwila, Sri Lanka Sao Paulo State Univ, Dept Anim Sci, Sao Paulo, Brazil

Animals suffering from parasitism typically display altered grazing behaviour and a voluntary reduction in feed intake. These changes are potentially important as indicators of disease. Recent advances in sensor technologies provide the opportunity to objectively measure animal activity while on pasture. Tri-axial accelerometers measure body movement in terms of acceleration, which can then be used to estimate physical activity over time. This study investigated if tri-axial measures of overall activity can be used to assess the impact of gastrointestinal nematode (GIN) infection in young sheep. To address this, the overall activity, faecal nematode egg count (FEC) and body weight of two treatment groups of Romney X Suffolk ram lambs were compared. Animals were monitored for four days using tri-axial accelerometer sensors mounted on a ram mating harness after 42-days grazing on contaminated pasture. On Day 0, all lambs were given anthelmintics. Subsequently, a Suppressive Treatment Group (n = 12) was treated with anthelmintics every two weeks. An Untreated Group (n = 12) did not receive further anthelmintics. Overall activity levels were monitored from Day 42 – 46. Activity level was calculated as vectorial dynamic body acceleration (VeDBA). Anthelmintic treatment had a significant effect on FEC but there was no evidence found for a treatment effect on body weight growth over the 42-day period. An effect of treatment and lamb starting weight on overall activity was found (beta = –0.74, 95 % CI –1.17 to –0.30, p = 0.002), identifying a negative impact of parasitism on activity in heavier animals. These results highlight the usefulness of this approach in assessing the effect of GIN parasitism on sheep monitored remotely. If a threshold value of activity could be determined, it could provide a useful tool for farmers and managers that serves as an early indicator of parasitism in sheep.

Objective: An experiment was designed to determine if behaviour traits expressed by twinand triplet-bearing lambs and their dams at 3 to 18 hours of age (after the immediate ewelamb bonding had occurred) were associated with lamb survival to weaning.Methods: The behaviour of twin and triplet lambs and their dams was assessed in the paddock at 3 to 18 hours after birth. Observations were made of the number of high- and low-pitched bleats, time to stand, make contact with dam, suck from dam and follow dam were recorded for each lamb. The maternal behaviour score of each dam was assessed. A random sub-sample of lambs were assessed during a maternal-recognition test at 12 or 24 hours of age. Traits included time spent standing, sitting, walking, time taken to reach the ewes and time spent with the ewes as well as the number of high- and low-pitched bleats emitted by the lamb.Results: In the paddock, for each additional second required for twin-born lambs to follow their dam, lambs were 1.004 (95% confidence interval [CI] 1.000 to 1.008) times more likely to survive to weaning (p

Sheep liveweight and liveweight change are vital tools both for commercial and research farm management. However, they can be unreliable when collection procedures are not standardized or when there are varying time delays between sheep removal from grazing and weighing. This study had two stages with different objectives: (1) A liveweight loss study to determine the effect of herbage availability (Low and High) on the rate of liveweight loss of ewes at different pregnancy stages (approximately 100 days of pregnancy: P100 and 130 days: P130) and ranks (single and twin), (2) A follow-up liveweight loss study to develop and validate correction equations for delayed liveweights by applying them to data sets collected under commercial conditions. Results from each stage showed that the rate of liveweight loss varied by herbage availability and stage of pregnancy (p &lt, 0.05) but not pregnancy-rank (p &gt, 0.05). Further, the rate of liveweight loss differed by farm (p &lt, 0.05). Applying liveweight correction equations increased the accuracy of without delay liveweight estimates in P100 ewes by 56% and 45% for single-bearing and twin-bearing ewes, respectively, when offered the Low-level diet. In ewes offered the High-level diet, accuracies of without delay liveweight estimates were increased by 53% and 67% for single-bearing and twin-bearing ewes, respectively. Among P130 ewes, accuracy was increased by 43% and 37% for single-bearing and twin-bearing ewes, respectively, when offered the Low herbage level and by 60% and 50% for single-bearing and twin-bearing ewes, respectively, when offered the High herbage level. In conclusion, a short-term delay of up to 8 hours prior to weighing, which is commonly associated with practical handling operations, significantly reduced the liveweight recorded for individual sheep. Using delayed liveweights on commercial farms and in research can have consequences for management practices and research results, thus, liveweight data should be collected without delay. However, when this is not feasible, delayed ewe liveweights should be corrected and, in the absence of locally devised correction equations, the ones generated in the current study could be applied on farms with similar management conditions and herbage type.

The objective was to determine whether grazing lucerne for 7 days before breeding and for the first 7 days of breeding affected the reproductive performance of ewes with different body condition scores (average of 3.2 versus 3.7). This was compared with grazing a grass-based sward with a high proportion of dead herbage that was available at the time of breeding in a summer dry region (Wairarapa) in autumn 2016. The lucerne contained large amounts of fungal infected stem and dead herbage, which induced high levels of coumestrol (107 ± 15 mg/kg DM). By the end of the feeding period the grass and lucerne on offer were both of low quality (7.8 MJ ME/kg DM). Ewes that grazed lucerne for 7 days before breeding and for the first 7 days of the breeding period produced 18 fewer (P

Ewe lamb breeding is a means for farmers to further increase the number of lambs available for sale each year while concurrently increasing the ewe lamb’s lifetime productivity. This study included 7666 replacement ewe lambs from two commercial New Zealand sheep farms that were presented for breeding during their first breeding season (aged 7–8 months) and were subsequently identified as pregnant. Ewe lambs were weighed and body condition scored (BCS) immediately pre-breeding, at pregnancy diagnosis (PD) and immediately prior to lambing (set-stocking). Logistic regression models were developed to assess the effect of liveweight and liveweight changes (both conceptus adjusted and non-adjusted) and BCS at breeding, PD and set-stocking on the risk of failure to rear a lamb (dry) to tail removal and castration (docking) where lambs are three to six weeks of age. There was no effect (p > 0.05) of breeding weight on the risk of being dry. There was an effect (p

To investigate associations between changes in liveweight and fetal loss in ewe lambs and to determine whether fetal loss was associated with concentrations of progesterone in early and mid-gestation.Ewe lambs on two commercial sheep farms (Flock A; n=504 and Flock B; n=460) in the southern North Island of New Zealand were weighed, and body condition score was assessed, prior to breeding and throughout pregnancy. Pregnancy diagnosis was undertaken approximately 56 (PD1), 80 (PD2) and 110 (PD3) days after the start of breeding and fetal loss determined. Blood samples were collected from a cohort of 407 ewe lambs between 45-54 and 73-84 days of gestation. Those that subsequently were diagnosed with fetal loss (n=16) were matched with ewe lambs that maintained pregnancy (n=16), and concentrations of progesterone were measured in the plasma samples from these animals.Fetal loss was diagnosed in 55/472 (11.7%) pregnant ewes from Flock A and 14/378 (3.7%) from Flock B. In both flocks the change in conceptus-free liveweight (CFLW) between PD1 and PD2 differed between ewe lambs with and without fetal loss; in Flock A the mean change was -59.9 (95% CI=-80.1 to -39.7) g/day vs. -3.43 (95% CI=-9.8 to 3.0) g/day (p0.001), and in Flock B the change was -38.5 (95% CI=-78.9 to 1.94) g/day vs. 79.5 (95% CI=72.6-86.4) g/day (p0.001). Similarly in Flock A the mean increase in CFLW between PD2 and PD3 was lower in ewe lambs with fetal loss than in those that maintained pregnancy (25.8 (95% CI=-13.8 to 65.4) g/day vs. 181.9 (95% CI=175.1-188.7) g/day) (p0.001). There was no difference (p0.05) in early and mid-gestation mean concentrations of progesterone in plasma between ewe lambs that had fetal loss compared with those that maintained pregnancy.Ewe lambs with fetal loss had a marked reduction in CFLW in the 24-30 days leading up to the identification of the fetal loss compared with those that maintained pregnancy. Early and mid-gestation concentrations of progesterone in plasma were similar between ewe lambs who went on to have fetal loss and those that maintained pregnancy.

Sheep (Ovis aries) liveweight and liveweight change can contain errors when collection procedures are not standardized, or when there are varying time delays between removal from grazing and weighing. A two-stage study was conducted to determine the effect of herbage availability and season of year on the rate of liveweight loss during fasting and to develop and validate correction equations applied to sets of delayed liveweights collected under commercial conditions. Results showed that ewe lambs offered the Low herbage availability lost up to 1.7 kg and those offered the Medium or High herbage availability lost 2.4 kg during 8 h of delayed weighing without access to feed or drinking water. The rate of liveweight loss varied by season, herbage availability and farm (p &lt, 0.05). Applying correction equations on matching liveweight data collected under similar conditions, provided more accurate estimates (33–55%) of without delay liveweight than using the delayed liveweight. In conclusion, a short-term delay prior to weighing commonly associated with practical handling operations significantly reduced the liveweight recorded for individual sheep. Using delayed liveweights on commercial farms and in research can have significant consequences for management practices and research results globally, therefore, liveweight data should be collected without delay. However, when this is not feasible delayed liveweights should be corrected, and in the absence of locally formulated correction equations, the ones presented in this paper could be used.

The body condition score (BCS) in sheep (Ovis aries) is a widely used subjective measure of body condition. Body condition score and liveweight have been reported to be statistically and often linearly related in ewes. Therefore, it was hypothesized that current BCS could be accurately and indirectly predicted using a ewe&rsquo, s lifetime liveweight, liveweight change, and previous BCS record. Ewes born between 2011 and 2012 (n = 11,798) were followed from 8 months to approximately 67 months of age in New Zealand. Individual ewe data was collected on liveweight and body condition scores at each stage of the annual cycle (pre-breeding, pregnancy diagnosis, pre-lambing, and weaning). Linear regression models were fitted to predict BCS at a given ewe age and stage of the annual cycle using a ewe&rsquo, s lifetime liveweight records (liveweight alone models). Further, linear models were then fitted using previous BCS and changes in liveweight, in addition to the lifetime liveweight records (combined models). Using the combined models improved (p &lt, 0.01) the R2 value by 39.8% (from 0.32 to 0.45) and lowered the average prediction error by 10% to 12% (from 0.29 to 0.26 body condition scores). However, a significant portion of the variability in BCS remained unaccounted for (39% to 89%) even in the combined models. The procedures found in this study, therefore, may overestimate or underestimate measures by 0.23 to 0.32 BCS, which could substantially change the status of the ewe, leading to incorrect management decisions. However, the findings do still suggest that there is potential for predicting ewe BCS from liveweight using linear regression if the key variables affecting the relationship between BCS and liveweight are accounted for.

This study determined the nature of the relationship between liveweight and body condition score (BCS) and assessed the influence of the stage of the annual cycle and pregnancy-rank on the relationship between liveweight and BCS in Romney ewes. Data were collected from the same ewes at different ages (8&ndash, 18, 19&ndash, 30, 31&ndash, 42, 43&ndash, 54, 55&ndash, 66 and &ge, 67 months), stages of the annual cycle (pre-breeding, at pregnancy diagnosis, pre-lambing and weaning) and pregnancy-rank (non-pregnant, single or twin). Linear regression was determined as being sufficient to accurately describe the relationship between liveweight and BCS. Across all data, a one-unit change in BCS was associated with 6.2 &plusmn, 0.05 kg liveweight, however, this differed by stage of the cycle, pregnancy-rank and ewe age (p &lt, 0.05). The average liveweight per unit change in body condition score increased with the age of the ewe and was greatest at weaning and lowest pre-lambing. Among pregnancy-ranks, the average liveweight per unit change was also greater during pregnancy diagnosis than pre-lambing and was greatest among single and lowest in non-pregnant ewes. The results support the hypothesis that the relationship between liveweight and BCS is affected by the interaction between stage of the annual cycle, pregnancy-rank and ewe age.

AIMS Firstly, to investigate associations between liveweight and body condition score (BCS) of two-tooth ewes (18-months-old at breeding) at breeding, pregnancy diagnosis (PD) and pre-lambing and the risk of being dry at docking, on commercial New Zealand sheep farms. Secondly, to investigate the association between previous reproductive outcomes as ewe lambs, and risk of being dry at docking as two-tooth ewes. METHODS Two-tooth ewes (n=9,006) were enrolled in four cohorts from three commercial sheep farms between 2010-14. Ewes were weighed and BCS assessed immediately pre-breeding, at PD (mid-pregnancy) and pre-lambing. At PD, ewes were identified as either non-pregnant, or having single or multiple fetuses. Palpation and examination of udders at docking was used to classify each ewe as either lactating or dry at docking. RESULTS Overall, 437/8,025 (5.4%) of ewes that were diagnosed pregnant at PD were dry at docking. The risk of being dry at docking decreased with increasing pre-lambing conceptus adjusted liveweight (CALW) on all farms (p≤0.002); for 2010-born ewes from Farm A the OR=0.87 (95% CI=0.81-0.92); for Farm B the OR=0.88 (95% CI=0.83-0.92) and for Farm C the OR=0.86 (95% CI=0.79-0.95). The risk of being dry at docking also decreased with increasing CALW gain from PD to pre-lambing for all farms (p≤0.003); for 2010-born ewes from Farm A the OR=0.89 (95% CI=0.84-0.94); for Farm B the OR=0.85 (95% CI=0.81-0.89) and for Farm C the OR=0.88 (95% CI=0.80-0.96). There was no association between BCS at breeding, PD or pre-lambing and the risk of being dry at docking for 2010-born ewes from Farm A, Farm B or Farm C (p0.05). For 2010-born ewes on Farm A, the risk of being dry at docking was greater for two-tooth ewes that were previously dry at docking as ewe lambs than those that were lactating at docking as ewe lambs (OR=1.7 (95% CI=1.1-2.8); p=0.018), but this difference was not observed for ewes on Farm B or Farm C (p0.5). CONCLUSIONS There were negative associations between ewe CALW pre-lambing, and CALW gain between PD and pre-lambing, and risk of being dry at docking. For all cohorts, heavier ewes and those that gained CALW were less likely to be dry at docking than lighter ewes or those that lost CALW, however these relationships varied between cohorts.

Objective The aim of the present study was to identify the impact of early weaning of lambs at approximately seven weeks of age onto a herb-clover mix on the liveweight gain of lambs and their dams. Methods In 2015, twin-born lambs that weighed a minimum of 16 kg (n = 134) were randomly allocated to one of three treatments: i) Early-weaned (58 days after the midpoint of lambing) onto an unrestricted allowance (>1,200 kg dry matter/ha) of herb-clover mix (HerbEW); ii) Lambs+dams unweaned onto an unrestricted allowance of herb-clover mix until conventional weaning (95 days after the midpoint of lambing) (HerbCW); iii) Lambs+ dams unweaned onto an unrestricted allowance of grass-clover pasture until conventional weaning (GrassCW). In 2016, twin-born lambs that weighed a minimum of 16 kg (n = 170) were randomly allocated to one of four treatments: i), ii), iii) (similar to 2015) and iv) Lambs+ dams unweaned onto a restricted allowance (0.05), but were greater than HerbEW lambs. In 2016, HerbCW lambs had greater (p0.05) but were greater (p

The objective of this study was to determine the relationships between ewe lamb live weight and body condition score immediately prior to breeding with fertility (ewes pregnant per 100 ewes bred) and reproductive rates (fetuses per 100 ewes bred). Over 2 years, ewe lambs on seven commercial sheep farms in the North Island of New Zealand were monitored during the breeding period until pregnancy diagnosis. Live weight and body condition score were recorded prior to breeding. Fertility rates increased with live weight up to 47.4 kg but did not increase above this (P > 0.05). Reproductive rate peaked for ewes in the 47.5–52.4 kg breeding live weight category at 138% (133%–143%). Ewe fertility peaked at a body condition score (BCS) of 3.5 (90% [88%–91%]) while reproductive rates peaked at a BCS of 3.0 (130% [127%–133%]). The apparent plateauing of the relationship indicates there is a point at which no further benefits are gained from increasing live weight or BCS.

The present study evaluated the effect of controlled ryegrass-white clover herbage availability from day 128 until day 142 of pregnancy in comparison to unrestricted availability, on the performance of twin-bearing ewes of varying body condition score (BCS; 2.0, 2.5, or 3.0) and their lambs. It was hypothesised that under conditions of controlled herbage availability, the performance of lambs born to ewes with a greater BCS would be greater than those born to ewes with a lower BCS. During the period that the nutritional regimens were imposed, the pre- and post-grazing herbage masses of the Control regimen (1,070±69 and 801±30 kg dry matter [DM]/ha) were lower than the ad libitum regimen (1,784±69 and 1,333±33 kg DM/ha; p0.05). The difference in ewe BCSs and back fats observed among body condition groups was maintained throughout pregnancy (p0.05). Ewe BCS group had no effect on lamb live weight at birth or weaning or on maximal heat production (p>0.05). Serum gamma glutamyl transferase concentrations of lambs born to BCS3.0 ewes were higher within 36 hours of birth than lambs born to BCS2.0 ewes and BCS2.5 ewes (51.8±1.9 vs 46.5±1.9 and 45.6±1.9 IU/mL, respectively [p0.05). Lamb survival was the only lamb parameter that showed an interaction between ewe nutritional regimen and ewe BCS whereby survival of lambs born to BCS2.5 and BCS3.0 ewes differed but only within the Control nutritional regimen ewes (p

Carcass attributes and meat quality characteristics of the Longissimus thoracis muscle were evaluated from 135 lambs from 9 commercial forage production systems (n = 15) on 3 farms. Wethers had greater eye muscle area and loin intramuscular fat percentage than cryptorchid lambs (P 0.05). Lambs that were processed at weaning had heavier carcasses and greater loin intramuscular fat percentage and shear force values than lambs slaughtered after further finishing on pasture or chicory (P

One of the limiting factors to the adoption of breeding 7-month-old ewes is that their lambs are lighter at birth and weaning than lambs born to mature ewes. The present study tested the hypothesis that the live weight and body condition score of 7-month-old ewes at breeding and during pregnancy would influence the live weight of their singleton-born lambs to weaning. Data was collected on one commercial sheep farm from 591 ewes across two years. In 2011 and 2012, during pregnancy the ewes gained 14.6 and 10.1 kg of total live weight, respectively. Multiple regression analysis indicated that live weight of ewes at breeding had a positive effect ( P P R -square of the model for lamb birth weight was small ( R 2 = 0.01) indicating, that live weight of the ewe was not a major contributor to the live weight of lambs at birth. The live weight of ewes in late pregnancy had a positive impact on both the live weight of lambs at approximately 18 days of age and at weaning ( P R 2 value for the multiple regression was small (0.01). Body condition score of the ewe at breeding and in mid-pregnancy had no effect ( P > 0.05) on lamb birth weight. In contrast ewes with body conditions scores of 3.5 and 4.0 or greater in late pregnancy gave birth to lighter lambs (4.9 ± 0.1 and 4.7 ± 0.2 kg, respectively) than ewes with body condition scores of 2.5 or less (5.3 ± 0.1 kg) or 3.0 (5.2 ± 0.1 kg, P P > 0.05) of ewe body condition score on lamb live weight at approximately 18 days of age or at weaning. Therefore, under the conditions of this study ewe live weight and condition score during pregnancy had a minimal effect of lamb live weight from birth to weaning.

Objective The present study aimed to determine the impact of ewe body condition score (BCS) (over a range of 2.0 to 3.0) and nutritional treatments (consisting of differing herbage masses) during very late pregnancy and lactation and their potential interaction on the performance of twin-bearing ewes and their lambs to weaning. Methods On day 142 of pregnancy, twin-bearing ewes with a BCS of 2.0, 2.5, or 3.0 were allocated to a “Moderate’ or ‘Unrestricted’ nutritional treatment until day 95 of lactation (weaning). The nutritional treatments aimed to achieve average herbage masses of 1,200 to 1,300 kg dry matter (DM)/ha (Moderate) and 1,500 to 1,800 kg DM/ha (Unrestricted). Results There were no three-way interactions between ewe BCS group, nutritional treatment and time for any ewe or lamb parameter. The nutritional treatments had no effect (p>0.05) on lamb birth or weaning weight. Lambs born to Moderate ewes had greater survival and total litter weight at weaning (p1,200 kg DM/ha during very late pregnancy and lactation.

Breeding ewe lambs is a management tool that can be used to increase farm profit. However, there are potential negative impacts on the liveweight of progeny at weaning and the liveweight of the ewe lamb at the following breeding. A potential method of minimising these impacts is through the provision of quality herbages such as lucerne or a herb mix containing chicory, plantain, and red and white clover. The aim of this 2-year study was to examine the impact of offering ewe lambs either a traditional ryegrass and white clover pasture (Pasture), Herb-mix or Lucerne throughout the lambing period and in lactation. During lactation in both years of the study, ewe lambs offered the Herb-mix or Lucerne treatments were heavier (P < 0.05) than those offered Pasture. In addition, progeny of ewe lambs offered the Herb-mix or Lucerne treatment were also heavier (P < 0.05) in lactation than those born onto ryegrass white clover. Interestingly, in one of the 2 years, the ewes and their progeny on the Lucerne treatment were heavier (P < 0.05) in lactation than those in the Herb-mix treatment. Combined, these results indicated that offering either Herb-mix or Lucerne increases the performance of the young dam and her progeny above that found on a ryegrass and white clover sward.

In sheep, maternal nutrition can affect the offspring’s milk production at its first lactation and the grand-offspring’s liveweight to weaning. However, this apparent developmental programming effect on milk production and grand-offspring liveweight has not persisted. Therefore, the aim of the present study was to determine if nutrition of the programmed ewe in mid- to late pregnancy affected this response. Developmentally programmed ewes (G1) that had been born from dams (G0) offered submaintenance, maintenance or ad libitum feeding levels from Day 21 to Day 50 of pregnancy and then either pregnancy maintenance or ad libitum to Day 140 were used for this study. These ewes were offered one of two pastoral-based pregnancy nutritional treatments (controlled vs unrestricted) from Day 76 of pregnancy until lambing. Pre- and post-herbage masses of the unrestricted treatment (2181 ± 47.6 and 1431 ± 24.6 kg DM/ha, respectively), were greater (P < 0.05) than the controlled treatment (1164 ± 31.6 and 819 ± 16.0 kg DM/ha, respectively). At Day 71 of pregnancy, there were no differences (P > 0.05) in G1 liveweight (70.2 ± 0.8 vs 70.3 ± 0.8 kg for controlled and unrestricted feeding, respectively), or body condition scores (2.5 ± 0.06 vs 2.5 ± 0.05) between pregnancy nutritional treatments. In late pregnancy, unrestricted G1 ewes were heavier (P < 0.05, 97.4 ± 1.0 vs 86.8 ± 1.0 kg) and had greater (P < 0.05) body condition scores (3.4 ± 0.06 vs 2.5 ± 0.06) and back-fat depths (8.0 ± 0.3 vs 5.9 ± 0.03 mm) than controlled nutritional treatment ewes. There were no interactions (P > 0.05) between grand-dam feeding levels and ewe nutritional treatment on lamb (G2) liveweights at birth or in lactation. This indicates that under the conditions of the present study, nutrition of the G1 ewe did not affect the expression of the developmental programming effect. Further studies might be warranted to determine the causes of this inconsistency in grand-offspring liveweight. Nutrition of the G1 ewe had a minor effect (P < 0.05) on G2 lamb birthweight and liveweight in early lactation but not (P > 0.05) in late lactation or on lamb survival. These findings indicate there is no little to no benefit to the lamb until weaning from offering ewes pre- and post-grazing masses above ~1200 and 800 kg DM/ha, respectively, in mid- to late pregnancy.