Lambing Rate Research Articles

Heterogeneity of variance components for preweaning growth in Romane sheep due to the number of lambs reared

BackgroundThe pre-weaning growth rate of lambs, an important component of meat market production, is affected by maternal and direct genetic effects. The French genetic evaluation model takes into account the number of lambs suckled by applying a multiplicative factor (1 for a lamb reared as a single, 0.7 for twin-reared lambs) to the maternal genetic effect, in addition to including the birth*rearing type combination as a fixed effect, which acts on the mean. However, little evidence has been provided to justify the use of this multiplicative model. The two main objectives of the present study were to determine, by comparing models of analysis, 1) whether pre-weaning growth is the same trait in single- and twin-reared lambs and 2) whether the multiplicative coefficient represents a good approach for taking this possible difference into account.MethodsData on the pre-weaning growth rate, defined as the average daily gain from birth to 45 days of age on 29,612 Romane lambs born between 1987 and 2009 at the experimental farm of La Sapinière (INRA-France) were used to compare eight models that account for the number of lambs per dam reared in various ways. Models were compared using the Akaike information criteria.ResultsThe model that best fitted the data assumed that 1) direct (maternal) effects correspond to the same trait regardless of the number of lambs reared, 2) the permanent environmental effects and variances associated with the dam depend on the number of lambs reared and 3) the residual variance depends on the number of lambs reared. Even though this model fitted the data better than a model that included a multiplicative coefficient, little difference was found between EBV from the different models (the correlation between EBV varied from 0.979 to 0.999).ConclusionsBased on experimental data, the current genetic evaluation model can be improved to better take into account the number of lambs reared. Thus, it would be of interest to evaluate this model on field data and update the genetic evaluation model based on the results obtained.

Worm control practice against gastro-intestinal parasites in Norwegian sheep and goat flocks.

BackgroundAnthelmintic treatment is the most common way of controlling nematode infections in ruminants. However, several countries have reported anthelmintic resistance (AR), representing a limitation for sustainable small ruminant production. The knowledge regarding worm control management represents a baseline to develop a guideline for preventing AR. The aim of the present study was therefore to improve our knowledge about the worm control practices in small ruminant flocks in Norway.MethodsA questionnaire survey regarding worm control practices was performed in small ruminant flocks in Norway. Flocks were selected from the three main areas of small ruminant farming, i.e. the coastal, inland and northern areas. A total of 825 questionnaires, comprising 587 sheep flocks (return rate of 51.3%) and 238 goat flocks (52.6%) were included.ResultsThe results indicated that visual appraisal of individual weight was the most common means of estimating the anthelmintic dose used in sheep (78.6%) and goat (85.1%) flocks. The mean yearly drenching rate in lambs and ewes were 2.5 ± 1.7 and 1.9 ± 1.1, respectively, whereas it was 1.0 (once a year) in goats. However, these figures were higher in sheep in the coastal area with a rate of 3.4 and 2.2 in lambs and ewes, respectively. Benzimidazoles were the predominant anthelmintic class used in sheep flocks (64.9% in 2007), whereas benzimidazoles and macrocyclic lactones were both equally used in dairy goat flocks. In the period of 2005-2007, 46.3% of the sheep flocks never changed the anthelmintic class. The dose and move strategy was practiced in 33.2% of the sheep flocks.ConclusionsThe present study showed that inaccurate weight calculation gives a risk of under-dosing in over 90% of the sheep and goat flocks in Norway. Taken together with a high treatment frequency in lambs, a lack of anthelmintic class rotation and the common use of a dose-and-move strategy, a real danger for development of anthelmintic resistance (AR) seems to exist in Norwegian sheep and goat flocks. This risk seems particularly high in coastal areas where high treatment frequencies in lambs were recorded.

High mortality in Leccese inbred lambs

The following investigation arose out of the observation of a high mortality rate in lambs belonging to a “closed” flock of Leccese sheep reared in Apulia region. The most common cause of death in the flock (34 out of 42 lambs) was enterotoxaemia caused by Clostridum perfringens. Due to the high inbreeding level in this population, the aim of this study was to determine whether inbreeding in Leccese lambs decreases their resistance to clostridial enterotoxaemia. All the animals were initially grouped into two classes (outbred, inbred) on the basis of their inbreeding coefficient. The percentage of dead lambs in outbred class was significantly different if compared to that found in inbred class (7.14% vs. 71.43% respectively, P < 0.001). No significant difference was observed by comparing animals with different inbreeding coefficient ( F < 10% vs. F ≥ 10%).

Alternative feedstuffs and their effects on performance of Awassi sheep: a review

Fat-tailed sheep (FTS) is a group of breeds characterized by large (fatty) tails that it is commonly distributed in Africa, Middle East, Pakistan, and to a lesser extent in other countries. Awassi, a common FTS breed in many Mediterranean countries, is adaptive and suitable to live in harsh conditions of the arid and semiarid areas. One of the main constraints for sheep industry in those areas is the limited supply and variable quality and quantity of feedstuffs. Using several alternative feedstuffs (AF) has been a common practice to decrease production cost of Awassi sheep industry in those areas. The appropriate AF to be used is determined by several animal and feed factors. These AF includes, but not limited to, unconventional feedstuffs, agricultural byproducts, and agro-industrial byproducts. A good body of literature about the use of AF and the effects of such use on performance of Awassi sheep is available. Some of these AF have been shown to be safely used in Awassi diets with no detrimental effects on sheep performance or health and, thus, recommended to lower the production cost. Other AF has controversial effects and recommendations. This paper reviews the effects of using AF on performance of Awassi ewes and lambs. Effects on intake, nutrient digestibilities, growth rate, and carcass characteristics of lambs and on intake, nutrient digestibilities, body weight change, milk yield, and milk composition of ewes will be emphasized. Recommendations and limitations for using AF will also be briefly discussed.

Economic weights of production and functional traits for Merinolandschaf, Romney, Romanov and Sumavska sheep in the Czech Republic

Economic weights of production and functional traits were estimated for the dual-purpose sheep breeds Romney (RY), Merinolandschaf (ML), Romanov (RV) and Sumavska (SA). A bio-economic computer model simulating the profit function for production systems with one lambing per year was used for the calculations. First, marginal economic values were calculated which were defined as partial derivatives of the profit function with respect to the average level for each trait. Applying gene-flow methodology, absolute and relative economic weights for direct and maternal components of the traits were then estimated for pure-bred production systems and systems which included partial terminal cross-breeding. The following traits were evaluated: birth weight, daily gain till weaning and during rearing, mature weight, dressing percentage, fleece weight, conception rate of ewe lambs and ewes, litter size at lambing (total number of lambs born per ewe lambing), survival rate of lambs at birth and till weaning and productive lifetime of ewes. Standardized economic weights were calculated as the product of the economic weight and the genetic standard deviation of each trait or trait component. The total economic importance was defined as the sum of the absolute (not taking into account the sign) standardized economic weights over all traits and trait components, and relative economic weights were then computed as the standardized economic weights expressed as percentages of total economic importance. The direct components of survival rate at birth and till weaning, the direct component of daily gain till weaning and litter size had the highest relative economic weights (greater than 10%) in pure-bred systems in all four breeds. In ML and RV, the maternal component of lamb survival rate till weaning also had a relative economic weight exceeding 10%. In systems with partial terminal cross-breeding for all four breeds, relative economic weights of maternal traits and trait components were slightly larger than in pure-bred production systems, particularly for litter size. Based upon comparison of relative economic weights of traits among breeds, separate breeding goals for RY and RV are recommended, whereas a common breeding goal is deemed appropriate for ML and SA.

Good quality sheep embryos produced by superovulation treatment without the use of progesterone devices

Multiple ovulation and embryo transfer (MOET) is a very important tool for the genetic improvement and preservation of endangered livestock. However, the success of a MOET programme highly depends on the number of transferable embryos in response to a superovulation treatment. Thus, the aim of this study was to compare the number and quality of embryos produced during natural oestrus under porcine FSH treatment without the use of progesterone devices to more traditional protocols. Forty Sarda sheep were divided into 2 groups: without sponges (WS) (n = 20) and with sponges (S) containing 40mg FGA for 12 d (n = 20) (control group); 350 I.U. of porcine FSH per sheep was administered in eight decreasing doses twice daily starting four days after estrus was detected (Day 0) in group WS and 48 h before sponge removal in group S. A single i.m. dose of 125 μg of cloprostenol was administered on Day 6 after estrus in group WS to induce luteolysis. Sheep were naturally mated 24 h after cloprostenol injection or sponge removal. Seven days after mating, an inguinal laparotomy was performed and the number of corpora lutea (CL) recorded. Embryos were recovered surgically by flushing each uterine horn. A total of 38 fresh and 22 vitrified embryos were transferred in pairs into 3 groups of recipients seven days after estrus detection: fresh embryos from group S (S-F) (n = 9), fresh embryos from group WS (WS-F) (n = 10) and vitrified embryos from group WS (WS-V) (n = 11). Data on the number of corpora lutea (CL), recovered ova and embryos (OER), and quality 1–2 and 3 embryos (EQ 1-2, EQ 3) per ewe were analyzed by ANOVA. Recovery (RR), fertility (FR) and quality 1–2 embryo (Q 1-2R) rates per treatment were analyzed by a Chi Square analysis. A Chi Square analysis was also applied to pregnancy rate (PR), lambing rate (LR) and twinning rate (TR) of fresh and vitrified embryos in order to analyze embryo transfer results. Among all superovulation variables analysed, results show statistically significant differences in mean number of CL/ ewe (9.3 ± 3.9 vs 7 ± 3.2), RR (67% vs 80 %) and FR (100% vs 80%) (P < 0.05) between WS and S groups respectively. There were no significant differences in PR (78%, 70% and 82%), LR (67%, 60% and 59%) and TR (71%, 71% and 44.4%) among S-F, WS-F and WS-V groups respectively. In conclusion, it is possible to produce a good number of transferable embryos during natural oestrus avoiding the use of sponges.

The effect of forage species on performance and gastrointestinal nematode infection in lambs

An experiment was designed to determine the effect of forage species on growth rate and gastrointestinal nematode infection in lambs. Southdown lambs ( n = 20; 26 ± 4.28 kg initial BW) stratified by weight, sex and FAMACHA© score were assigned to graze either bermudagrass [BG; Cynodon dactylon (L.) Pers.] or chicory [CH; Cichorium intybus L.]. Lambs grazed for 80 d from July 7, 2009 to September 25, 2009. Lambs were weighed and FAMACHA© scored every 14 d. Fecal samples were taken on d 14, 42, 56, and 69 for modified McMaster fecal egg counts. Ultrasound measures of subcutaneous fat thickness (FT) over the 12th and 13th rib and longissimus dorsi muscle depth (MD) were taken on d 80. Lambs grazing CH had lower ( P < 0.01) FAMACHA© scores by d 69 than lambs grazing BG (2.4 ± 0.43 and 3.1 ± 0.59, respectively). By d 80 FAMACHA© scores were 2.0 ± 0.22 and 3.9 ± 0.64 ( P < 0.01) for CH and BG, respectively and fewer ( P < 0.01) CH lambs than BG lambs required anthelmintic treatment (0/10 and 7/10, respectively). CH lambs also exhibited lower ( P < 0.01) FEC than BG lambs. Average daily gain was greater ( P < 0.01) in lambs grazing CH than those grazing BG (0.28 ± 0.04 and 0.08 ± 0.02 kg/d, respectively). At the end of 80 d, weights were 49.2 ± 3.53 and 33.1 ± 3.82 kg ( P < 0.01) for CH and BG, respectively. On d 80, FT and MD were greater in CH lambs than those grazing BG ( P < 0.01). Lambs grazing CH had increased performance and reduced GIN infection compared to those grazing BG.

Reproductive Behavior and Efficiency in Pelibuey Ewes Treated with FGA-PMSG and Bred by Mounting or Laparoscopic Intrauterine Insemination

Quintero-Elisea, J.A., Vázquez-Armijo, J.F., Cienfuegos-Rivas, E.G., Correa-Calderón, A., Avendaño-Reyes, L., Macías-Cruz, U., Lucero-Magaña, F.A. and González-Reyna, A. 2010. Reproductive behavior and efficiency in Pelibuey ewes treated with FGA-PMSG and bred by mounting or laparoscopic intrauterine insemination. J. Appl. Anim. Res., 38: 13–16. To evaluate the effect of 200 IU of PMSG on reproductive behaviour of hair sheep ewes were bred by 1) intrauterine artificial insemination by laparoscopy (IAIL) or 2) natural mount (NM) in Northeast Mexico, and subjected to an estrus synchronization protocol, with fluorogestone acetate sponges for 10 d (40 mg, FGA). Twenty four hours before sponge withdrawal, the ewes were randomly assigned to one of two treatments, T1= 200 IU of PMSG (n= 40) IM or T2= 0 IU of PMSG (n=20). Ewes showing estrus, were divided in two groups, to be served by 1) MN or 2) by IAIL. The PMSG treatment reduced(P<0.0001)hours to estrus (HE) (25.8 h vs 37.7 h). The conception rate (CR) was smaller(P<0.05)in the PMSG treated ewes. In addition, the lambing rate (LR) and the fecundity (Fc) were smaller (P<0.05) in the ewes of the control group. The CR was lesser (P<0.05) for the IAIL group. The LR was lesser (P<0.05) in the ewes of the NM group. PMSG reduced the hours to estrus and increased the lambing rate; however, it will be necessary to determine the effect of PMSG dose, on the reproductive efficiency of the ewes. It is recommended to use an FGA+PMSG treatment for inducing the estrus, accompanied with IAIL to increase reproductive rate in hair sheep ewes.

Effect of thermal stress, restricted feeding and combined stresses (thermal stress and restricted feeding) on growth and plasma reproductive hormone levels of Malpura ewes under semi-arid tropical environment

A study was conducted to assess the effect of thermal, nutritional and combined stresses (thermal and nutritional) on the growth, oestradiol and progesterone levels during oestrus cycles in Malpura ewes. Twenty-eight adult Malpura ewes were used in the present study. The ewes were randomly allocated into four groups, viz., GI (n=7; control), GII (n=7; thermal stress), GIII (n=7; restricted feeding) and GIV (n=7; combined stress). The animals were stall fed with a diet consisting of 60% roughage and 40% concentrate. GI and GII ewes were provided with ad libitum feeding while GIII and GIV ewes were provided with restricted feed (30% intake of GI and GII ewes) to induce nutritional insufficiency. GII and GIV ewes were kept in climatic chamber at 40°C and 55% RH for 6 h a day between 10:00 and 16:00 hours to induce thermal stress for a period of two oestrous cycles. Parameters studied were body weight, oestrus incidences, plasma oestradiol 17-β, plasma progesterone, conception rate, gestation period, lambing rate, and birth weight of lambs. The results indicate that combined stress significantly (p<0.05) reduced body weight, oestrus duration, birth weight of lambs, and oestradiol 17-β whereas significantly (p < 0.05) increased oestrus cycle length and progesterone. Furthermore, the results reveal that on comparative basis, ewes were able to better adapt in terms of growth and reproduction to restricted feeding than thermal stress. However, when restricted feeding was coupled with thermal stress it had significant (p<0.05) influence on body weight, average daily gain, oestradiol 17-β and progesterone concentrations. This showed that combined stress were more detrimental for these reproductive hormones in Malpura ewes under a hot semi-arid environment.

Modulation of Baroreflex Sensitivity by Endogenous Angiotensins in Lamb Solitary Tract Nucleus

We and others find that within the nucleus of the solitary tract (NTS) of the rat endogenous Ang II attenuates while Ang‐(1–7) facilitates the baroreflex sensitivity (BRS) in the control of heart rate. It is not known whether this same relationship exists in the sheep NTS. Therefore, we performed microinjection studies in 6 wk old sheep (n = 5) under chloralose‐urethane anesthesia (35/750 mg/kg) which maintains both increases and decreases in BRS for heart rate control. To assess the effects of blockade of either the AT1 or Ang‐(1–7) (AT7) receptors, we tested BRS before and after bilateral NTS injection of the AT1 antagonist candesartan (CV, 200 pmol/200 nl at 4 injection sites) and retested the reflex again after the AT7 antagonist D‐Ala7‐Ang‐(1–7) (D‐Ala, 10 pmol/200 nl at 4 injection sites). BRS was tested using various doses of phenylephrine to determine the slope of the relationship between changes in mean arterial pressure (MAP) and pulse interval as ms/mm Hg. Resting BRS was 0.3 ± 0.2 ms/mm Hg and MAP was 81 ± 7 mm Hg. NTS injection of CV increased BRS to a new baseline of 1.0 ± 0.2 ms/mm Hg, (p&lt;0.05). From this elevated level D‐Ala significantly reduced BRS back to baseline. There was no effect of either agent on MAP. These data suggest that baseline baroreceptor reflex control of heart rate in lambs is regulated by Ang II and Ang‐(1–7) in the NTS in an opposite manner. Support: HD‐047584, HD‐017644, HL‐51952.

Effect of breed type and ionophore supplementation on growth and carcass characteristic in feedlot hair lambs

The effects of supplementing feedlot diets with ionophores and breed type were assessed on growth rate and carcass characteristics in hair lambs. Twenty four intact males, 12 Pelibuey × Dorper (PDo) and 12 Pelibuey × Damara (PDa) lambs, 17.9 ± 3.7 kg initial weight, were housed in individual pens for a 60-d feeding trial. The lambs were assigned randomly into four diets: control without additives (C); 25 µg/g monensin (M); 28 µg/g salinomycin (S); 28 µg/g S for 20 d, and 25 µg/g M for the next 40 d (SM). Each diet was supplied to six lambs. Data were analyzed as a randomized complete block design in a 4 × 2 factorial arrangement, with four diets and two breed types of hair lambs (PDo and PDa). All diets were formulated to contain 14% CP and 2.6 Mcal ME/kg dry matter. At the end of the feeding trial carcass images were recorded in the last intercostal space (12th and 13th ribs) using ultrasound equipment to measure the Longissimus dorsi muscle area and subcutaneous fat (SF). The average daily gain (ADG), daily dry matter intake, feed:gain ratio, subcutaneous fat and Longissimus dorsi area were not affected by ionophore supplementation.. The Pelibuey × Dorper group tended to show better average daily gain than Pelibuey × Damara (262 g/d and 235 g/d, respectively). Daily dry matter intake, feed:gain ratio and subcutaneous fat were not affected by breed type. The Pelibuey × Dorper lambs had greater Longissimus dorsi area (16.74 cm²) than the Pelibuey × Damara (14.29 cm²) lambs. The growth rate was not influenced by the inclusion of ionophores. Pelibuey × Dorper lambs showed better average daily gain and carcass characteristics than Pelibuey × Damara lambs.

Factors Affecting the Fertility of Ewes after Intrauterine Insemination with Frozen-Thawed Semen During the Non-Breeding Season

In this study, two successive field trials were conducted during the non-breeding season to investigate various factors affecting on fertility of Suffolk ewes after intrauterine insemination with frozen-thawed semen. In the first year (Experiment 1), three sperm numbers per insemination dose (0.25, 0.5 and 1 million sperm) and five sheep farms were used, and in the second year (Experiment 2), parity, age, body weight, body condition score (BCS) and postpartum days were investigated to compare pregnancy and lambing rates. High pregnancy and lambing rates (70.6 and 70.6%, respectively) were obtained with 0.25 million sperm per dose. There were no significant differences in the pregnancy and lambing rates among the five farms, but there was a tendency for one farm to have higher pregnancy (75.8%, P=0.065) and lambing (72.7%, P=0.077) rates than those (46.7-53.3% and 45.2-53.3% for the pregnancy and lambing rates, respectively) of the other farms. In Experiment 2, ewe age significantly affected both the pregnancy and lambing rates. Nulliparous ewes had a higher lambing rate (72.0%) than that (44.2%) of multiparous ewes, but a significant difference was not revealed. Regardless of body weight, BCS tended to be an important factor influencing on fertility of ewes. Body weight and the postpartum days did not affect the fertility of ewes. It was concluded from these results that the fertility of Suffolk ewes after intrauterine insemination with frozen semen was significantly influenced by sperm number per dose and ewe age. Nulliparous ewes at less than three years of age and with a BCS of more than 3.0 are expected to have higher fertility than other ewes.

Minerals management in silvopastoral system of karst pasture

A survey of mountain pasture topsoil was undertaken first to set up field experiment in karst region on effects of applied P on minerals concentration in herbage. Content of SOM, C, N, CEC of soil and its base saturation are presented in the article. Great variability in depth, pH value and K level was found in soil. Low base saturation and high deficit of P was more common for all soil samples. Six different plant species presenting a great portion of herbage available for grazing and browsing at different occasions during grazing season were sampled and analysed for macro- and some microminerals. Concentration of P was very low in perennial grasses (1.1 g P kg−1 of DM). In leaves of common hazel (Corylus avellana L.) and common beech (Fagus silvatica L.) the concentration of P was identical as in white clover (Trifolium repens L.) and the level was high enough to cover animal needs when intake of herbage was sufficient. Leaves of woody plants were high in Mn concentration, but still below the levels that reduced growth rate in lambs. Application of P fertilizer had only small effect on increase of P in herbage, but large one on decrease on concentration of Ca in herbage. There was not clear effect of added P on concentration of Zn, Mn, Fe and Cu. Higher yield of DM induced with added fertilizer had not have any dilution effect on concentration of those minor elements in herbage.

Effect of feeding different types of roughage on the performance of pregnant Awassi ewes

This experiment was designed to study the performance of Awassi pregnant ewes fed different types of roughage (green, hay and silage) during late pregnancy. Twenty four Awassi ewes (initial weight 47.01 ± 0.9 Kg) aged 2-3 years mated in mid June were used in a three treatments completely randomized design. Animals were housed and grouply penned 8 weeks before lambing. Treatment 1 (G1) consisted of alfalfa green roughage, Treatment 2 (G2) was fed whole crop maize silage and treatment 3 (G3) was fed dried alfalfa hay. All treated ewes were fed roughages ad libitum pluse 200 g/day concentrate. Types of roughage had no significant effect on ewes body weight changes (changes from the start of the experimental feeding to 24 hours post lambing).Ewes fed green roughage (G1) had heavier post-lambing weight than G2 and G3. lambs born from group 1 were heavier (P<0.01) than G2 and G3. Similar results were obtained for growth rate and weaning weight of lambs.

Calculating economic values for growth and functional traits in non‐dairy sheep

A bio-economic model including a computer program was developed where a large number of parameters can be modified to describe a great variety of production systems. Economic values for up to 27 traits can be calculated. Seasonal feeding is considered and protein requirement in addition to net energy may be taken into account when calculating feed requirement. Furthermore, the model allows for the evaluation of individual parts of the growth curve. The model was applied to the Czech Suffolk breed used in pure-breeding. An extensive pasture system with spring lambing and sale of surplus progeny for slaughter after weaning or after a finishing period was assumed. The economic values (in Euro cent per ewe, per year and per genetic standard deviation of the trait) were as follows: 9.9 for birth weight, -72.6 for mature weight, 142, 32.1 and 16.9 for growth rates till weaning, in rearing of breeding animals and in fattening, respectively, 19.9 and 101 for conception rate of female lambs and ewes, respectively, 690 for litter size per ewe lambing, 172 for productive lifetime of ewes, 402 and 503 for survival rate of lambs at lambing and till weaning, respectively, and 16.5 for fleece weight.

Economic Values for Dairy Sheep Breeds in Slovakia

Economic values of 14 production and functional traits for two Slovak dairy sheep breeds (Improved Valachian and Tsigai) were calculated. Semi-extensive production systems with one lambing per year were simulated using a bio-economic deterministic computer model. The marginal economic value of a trait was defined as the partial derivative of the profit function with respect to that trait. The relative economic value expressed the percentage proportion of standardized economic value (marginal economic value×genetic standard deviation) of a trait in the sum of the absolute values of the standardized economic values over all traits. Milk yield was of highest relative importance (26% and 32% in Improved Valachian and Tsigai) followed by productive lifetime and conception rate of ewes (16% and 15% in Improved Valachian and Tsigai, in both traits). Conception rate of female lambs and litter size had nearly the same relative economic importance in both breeds (9% to 11%). Survival rate of lambs at lambing and till weaning reached slightly lower economic values (4% to 7%). The economic importance of all remaining traits was less than 4%. (Key Words : Dairy Sheep, Economic Weights, Milk Production, Functional Traits, Improved Valachian, Tsigai)

Body weight and blood parameters of Old Norse Sheep grazing coastal heathland

This study describes development in body weight and blood parameters of Old Norse Sheep grazing coastal heathland throughout the year without supplementary feeding. A group of approximately 80 ewes were observed for five years. The average body weight in October was 23.0 kg for lambs and 31.9 kg for ewes two years and older. The growth rate of lambs was 150–200 g/day during the first four months from birth but decreased to 51 g/day from August to October. The autumn weight increased the first five years of life. Ewes displayed weight loss and low levels of serum protein during winter, indicating moderate undernutrition. The weight loss was positively related to age and initial weight. The levels of vitamin B12 were higher than normally found in sheep on cultivated pasture. The serum levels of Ca, Mg and Cu were within the reference values, whereas the levels of inorganic P was slightly below the reference values.

Effect of individual or paired housing during post-weaning on feed intake, growth rate and behaviour of lambs

The aim of this study was to compare the behaviour and weight gain of weaned lambs penned either in pairs or alone, with visual and tactile contacts between pens. A 2 × 2 factorial experiment was conducted over seven weeks. Forty-eight Dorset lambs (twenty-five females and twenty-three males) were randomly distributed among pens. All pairs were non-twin lambs of the same sex. They were fed haylage (48.9% of DM) and a commercial pelleted feed both provided ad libitum. Weight of lambs was recorded at d0 and then weekly until d49. Consumption of dry matter and average daily gain (ADG) were also recorded. Lamb postures, activities and total bleats were directly observed in the morning and in the afternoon on six different days (d1, d2, d5, d12, d19, d26). On d1, observations were done only in the afternoon. For paired lambs, data were averaged by pen. Lambs penned alone were less active, slept more ( P < 0.03) and walked less ( P < 0.001) than paired lambs. Total bleats were not affected by housing treatment or sex, but were significantly higher for the first two days ( P < 0.0001). Lamb growth performance was unaffected by the type of housing ( P > 0.05). There was a significant difference in ADG ( P < 0.001), total gain ( P < 0.001), kg concentrate kg −1 gain ( P < 0.05) and final body weight ( P < 0.05) in favor of males as compared to females. Our results suggest that a housing system in which individually raised lambs are allowed visual, tactile, and auditive contact with each other, compared to lambs housed in pairs, does not impact negatively on their growth and behaviour.

Age dependent effects of haemorrhage on the arterial baroreflex control of heart rate in conscious lambs

Previously, we showed that arterial pressure decreased after moderate haemorrhage in conscious lambs, whereas a compensatory increase in heart rate occurred only in newborns. These findings provided evidence to suggest an age‐dependent effect of haemorrhage on the arterial baroreflex control of heart rate. Therefore, in the present study, the arterial baroreflex was assessed in conscious lambs aged 14±1 days (G I, N=4) and 43±7 days (G II, N=6) before (control, C) and at 30 and 60 min after haemorrhage (30% of calculated blood volume). The following parameters governing the arterial baroreflex were evaluated: Heart rate range (P1), slope coefficient (P2), systolic arterial pressure at midpoint (P3), minimum HR (P4), and maximum gain (Gmax). Values are mean±SEM; *p&lt;0.05 compared with C; †p&lt;0.05 compared with G I.Predominant effects of haemorrhage were: a decrease in P1 which was greater in G I than G II, and a decrease in Gmax which was greater in G II than G I. Therefore, severe haemorrhage alters several parameters governing the arterial baroreflex control of heart rate, these effects being developmentally regulated.This research was supported by the Canadian Institutes of Health Research (CIHR).

Effects of different levels replacement of ensiled pistachio epicarp with corn silage on fattening parameters and lamb performance

There is about 430000 hectares of pistachio garden in Iran and annual dry pistachio production is 688000 tones. There are some problems with this by-product are including: 1) deterioration in less than 24 hours so it could not stored for long term. 2) Pistachio epicarp contains high level of tannins and other phenolic compounds, and there is little information about its effects in ruminants. 3) This by-product is potentially an environmental pollutant and cost effective for disposal. A study was conducted to investigate possibility of different levels replacement of ensiled pistachio epicarp (EPE) with corn silage and its effects on growth rate and carcass composition of lambs.