Attainment of puberty and reproductive performance in Clun Forest ewe lambs

1972 ◽  
Vol 78 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Ó. R. Dýrmundsson ◽  
J. L. Lees
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Breeding Season ◽  
Reproductive Performance ◽  
First Year ◽  
Cyclic Activity ◽  
Breeding Activity ◽  
Ewe Lambs ◽  
Wide Range ◽  
The Mean

SUMMARYCertain aspects of puberal development and reproductive performance in Clun Forest ewe lambs with a wide range of birth dates were investigated during the two seasons 1969–71. Of 33 ewe lambs born in the spring of 1969, 26 exhibited their first oestrus at a mean date of 8 November 1969 ± 2·5 days, the mean age being 228·3 ± 2·4 days and the mean body weight 36·3 ± 0·9 kg. The lambs which failed to breed in their first year, together with lambs born in the autumn of 1969, attained puberty during the autumn of 1970. Twenty-three ewe lambs carried foetuses to term in the spring of 1970 and had a mean lambing rate of 113·0 ± 7%. Of 84 ewe lambs born in the spring of 1970, 73 attained puberty in the first year of life at a mean date of 11 November 1970 ± 2·7 days, the mean age being 223·7 ± 3·0 days and the mean body weight 32·2 ± 0·5 kg. Cyclic activity of ewe lambs born in 1970 was recorded throughout their first breeding season. They experienced their last oestrus of the season at a mean date of 24 January 1971 ± 2·2 days, the mean age being 296·9 ±3·9 days and the mean body weight 32·4 ± 0·6 kg. The mid-breeding season was 18 December 1970, coinciding with the shortest days, and the mean number of heats exhibited throughout the season was 5·15 ± 0·24 per lamb.Marked individual variation existed in age and body weight at puberty and in breeding activity, largely due to differences in date of birth and growth rate during rearing. Ewe lambs born early tended to experience their first oestrus earlier in the season than late born lambs but they did so at a higher age and heavier body weight. Fast growth rate and earliness of puberty were associated with extended duration and enhanced regularity of cyclic activity. Time of birth was clearly of fundamental importance in relation to the onset and duration of breeding activity in the ewe lambs included in the present study.Adult rams of three breeds were found to vary consistently in the proportion of ewe lambs which they detected in oestrus, rams of the lambs' own breed being most efficient.

Studies on the breeding season of Icelandic ewes and ewe lambs

1978 ◽  
Vol 90 (2) ◽  
pp. 275-281 ◽  
Author(s):  
Ø. R. Dýrmundsson
Keyword(s):  
Breeding Season ◽  
Individual Variation ◽  
First Year ◽  
Cyclic Activity ◽  
Breeding Activity ◽  
Ewe Lambs ◽  
The Mean ◽  
Considerable Individual Variation ◽  
A Minor ◽  
First Year Of Life

SummaryThe paper reports on a study, conducted in four successive seasons, of sexual development and breeding activity in females of the Iceland breed, the only breed of sheep kept in the country. The ewe lambs normally attained puberty in their first year of life, on average at 7 months of age, with marked individual variation in both age and body weight at first oestrus. Ewe lambs always showed oestrus on average slightly later than mature ewes (2–9 years), the mean date of onset of the breeding season of the latter being 8 December, however, with considerable individual variation. Furthermore, ewe lambs had a shorter breeding season (1–4 months) than ewes (4–6 months) and they appeared to experience more silent heats resulting in less regular cyclic activity. There seemed to be a minor increase in the duration of the oestrous cycle with age and ewe lambs clearly exhibited shorter oestrus (heat) than ewes. With seasonal breeding activity ranging from November to May the mid-breeding season occurs some 4–7 weeks after the shortest day.

Effect of autumn shearing on breeding activity in Clun Forest ewe lambs

1972 ◽  
Vol 79 (3) ◽  
pp. 431-433 ◽  
Author(s):  
Ó. R. Dýrmundsson ◽  
J. L. Lees
Keyword(s):  
Body Weight ◽  
Field Conditions ◽  
First Year ◽  
Cyclic Activity ◽  
Natural Field ◽  
Group Iii ◽  
Breeding Activity ◽  
Ewe Lambs ◽  
Stage Of Development ◽  
The Mean

SUMMARYSeventy-two Clun Forest ewe lambs were randomly stratified into three groups (I, II and III) of 24 each according to date of birth and body weight at 6 October 1970. The ewe lambs of Groups I and II were shorn on 15 and 30 October, respectively, and Group III acted as unshorn control. The ewe lambs were reared under natural field conditions but supplementary feeding and shelter were provided during the winter months.A large proportion (94%) of the ewe lambs attained puberty in their first year and differences between the three groups in the number of ewe lambs reaching this stage of development were small and not significant. Autumn shearing of ewe lambs was associated with a very slight but statistically wholly insignificant delay in the mean date of puberty whereas the duration of cyclic activity in these lambs was not affected by such treatments.

Effect of prolonged undernutrition on the recovery and reproductive performance of maiden Merino ewes

1967 ◽  
Vol 7 (24) ◽  
pp. 7 ◽  
Author(s):  
P McInnes ◽  
TJ Grainger ◽  
MD Smith
Keyword(s):  
Body Weight ◽  
Reproductive Performance ◽  
New South ◽  
New South Wales ◽  
The Other ◽  
First Year ◽  
Treatment Groups ◽  
South Wales ◽  
Feeding Trials ◽  
The Mean

Data are presented on the recovery and reproductive performance of 2 1/2-year-old maiden Merino ewes after a prolonged period of undernutrition. The 217 sheep had been hand-fed on a submaintenance ration in pen feeding trials at Glenfield, New South Wales. During the seven months of the trials they had lost 6 kg (28 to 22 kg) body weight. They were transported to Condobolin in south-western New South Wales, divided into two treatment groups and run on good quality pastures. One group was joined immediately (May 1959) and again ten months later, and the other group was mated after six months at Condobolin (in October 1959) and again 12 months later. The ewes recovered rapidly. The mean weight of both groups had reached 30 kg within six weeks and 40 kg within six months. In the first year 73 of the 100 May-mated ewes bore lambs, but only 38 of these lambs were weaned. Ewes bearing lambs had a higher body weight at the start of joining and gained more during joining than the barren ewes. At the other three joinings (October 1959, May 1960, October 1960) lambing percentage was from 86-89 and weaning percentage from 62-69-both normal for the district. The proportion of twin lambs (3-6 per cent) was low. Wool weight in 1959 was not affected by time of mating or by pregnancy.

Effect of body weight on the attainment of puberty and reproductive performance of Galway and Fingalway female lambs

1979 ◽  
Vol 28 (3) ◽  
pp. 297-307 ◽  
Author(s):  
J. F. Quirke
Keyword(s):  
Body Weight ◽  
Breeding Season ◽  
Litter Size ◽  
Conception Rate ◽  
Restricted Feeding ◽  
Ewe Lambs ◽  
Younger Age ◽  
Body Weights ◽  
The Mean ◽  
Ad Libitum

ABSTRACTGroups of spring-born Galway (G) and Fingalway (F) ewe lambs were fed a concentrate diet either ad libitum (H) or at a restricted level (L) during the period 25 July to 16 October 1974 in order to induce differences in body weight at the start of the breeding season. The mean live weights of the GL, GH, FL and FH groups on 16 October 1974 were 37·8 ± 1·3, 44·6 ± 1·3, 35·1 ± 1·1 and 41·9 ± 1·2 kg respectively. More than 95% of the lambs in all four groups attained puberty before 28 February 1975. Galway ewe lambs reached puberty later in the breeding season and were older and heavier at puberty than Fingalways. Animals fed ad libitum were heavier at puberty and attained puberty earlier in the season and at a younger age than those on the restricted feeding regime.Both conception rate and litter size were lower in Galways than Fingalways. There was no evidence of any effect of the nutritional treatments on conception rate or litter size. The mean body weights at puberty for ewes which lambed and those which were barren were 41·9 ± 0·49 and 41·5 ± 0·78 kg respectively. The birth weight and growth rate of the progeny of the ewe lambs was similar for the two breeds and was not influenced by the previous nutritional treatment of the dams. The total lamb mortality between birth and weaning was 40·3%, and 72% of all deaths occurred within 48 h of birth. Losses among twins (48%) were particularly heavy.

scholarly journals ​Production, Reproduction Performance and Cost Economics of Nellore Brown Lambs Reared under Different Systems of Rearing

2021 ◽  
Author(s):  
B. Rangamma ◽  
A. Sarat Chandra ◽  
N. Rajanna ◽  
M. Gnana Prakash ◽  
M. Venkateswarlu ◽  
...  
Keyword(s):  
Body Weight ◽  
Reproductive Performance ◽  
Live Weight ◽  
The Body ◽  
Research Station ◽  
Net Income ◽  
Reproductive Parameters ◽  
Ewe Lambs ◽  
The Mean ◽  
The Cost

Background: To know the production and reproductive performance of Nellore brown lambs under three systems i.e. intensive, semi-intensive and extensive system of rearing and which system of rearing was beneficial for the farmer community in terms of cost economics. Methods: 36 Nellore brown lambs of 3 months age from Livestock Research Station, Mamnoor, Warangal district were randomly allotted to three rearing systems i.e. Intensive (G1), Semi-intensive (G2) and Extensive (G3) system of each 12 animals. The body weight and ADG of lambs in the three systems were recorded fortnightly and calculated the cost economics. The reproductive parameters of ewe lambs were recorded. Result: From 3-9 months age, the mean gain in body weight (kg) in the G1 group was significantly (P less than 0.01) higher followed by G2 (10.95 ± 0.18) and G3 (9.33 ± 0.09) groups. The mean ADG (gm) was significantly (P less than 0.01) higher in G1 group (75.14 ± 1.56) than G2 (60.83 ± 1.02) and G3 (51.81 ± 0.47) groups. Significant (P less than 0.05) difference was observed in the mean age at puberty of ewe lambs in the three groups. The mean age at first service was lowest in G1 (329.50 ± 6.99) followed by G2 (360.17 ± 6.56) and G3 (385.17 ± 5.60) groups. The net income (Rs.) obtained from each lamb was 1870.8, 1406.7 and 1217.3, respectively in G1, G2 and G3 groups. The cost per kilogram live weight gain was higher in the G1 group followed by G2 and G3 group.

Effect of rams on the onset of breeding activity in Clun Forest ewe lambs

1972 ◽  
Vol 79 (2) ◽  
pp. 269-271 ◽  
Author(s):  
Ó. R. Dýrmundsson ◽  
J. L. Lees
Keyword(s):  
Body Weight ◽  
Breeding Activity ◽  
Ewe Lambs ◽  
Group A ◽  
The Mean ◽  
Group B ◽  
High Degree ◽  
Sudden Introduction

SUMMARYFifty Clun Forest ewe lambs with uniform birth dates were randomly stratified into two groups (A and B) of 25 each according to date of birth and body weight at 23 August 1971. On 26 August Group A (control) was joined with rams whilst Group B remained completely isolated from any contact with rams until 18 October.The sudden introduction of rams to ewe lambs in the transition from non-breeding to breeding activity resulted in a high degree of synchronization of first matings in Group B. However, it did not affect the mean date of onset of oestrous activity.

Variations in the time of onset of the breeding season in Clun ewes

1966 ◽  
Vol 67 (2) ◽  
pp. 173-179 ◽  
Author(s):  
J. L. Lees
Keyword(s):  
Ambient Temperature ◽  
Breeding Season ◽  
Cyclic Activity ◽  
Breeding Activity ◽  
The Mean ◽  
Limited Period

Variations in the time of onset of the breeding season in Clun ewes have been studied during the four years 1962-65. Differences within seasons were studied in 1963 and 1964 by scattering the lambing over the first 7 months of the year. The date of first service then appears to be very highly dependent on the date of previous lambing. Time of previous weaning appears to be less important.Very highly significant differences have been found between seasonal means and these differences have been shown to be significantly related to the mean ambient temperature during a limited period between mid-summer and the mean date for the resumption of cyclic activity in the ewes. The higher this temperature the later the onset of breeding activity. Over the years individual ewes have tended to breed consistently either early or late.

The effect of feed restriction on sexual maturity and initial reproductive performance of broiler pullets under different light treatments

1969 ◽  
Vol 9 (39) ◽  
pp. 417 ◽  
Author(s):  
RAE Pym ◽  
R Sledge
Keyword(s):  
Body Weight ◽  
Reproductive Performance ◽  
Sexual Maturity ◽  
Feed Restriction ◽  
Restricted Feeding ◽  
Egg Weight ◽  
Laying Performance ◽  
The Mean ◽  
The Difference ◽  
Lighting Systems

An experiment was conducted to examine the effect of restricted feeding under two lighting systems during the rearing period on the initial laying performance of broiler type pullets. The rearing treatments were imposed at nine weeks of age, removed at 22 weeks and the trial was discontinued at 36 weeks of age. The feeding treatments (restricted versus ad lib.) were arranged factorially with the lighting treatments (decreasing versus increasing). Birds reared on restricted feeding reached sexual maturity 16 days later than full fed birds, ate 17 per cent less feed to 22 weeks and gained seven per cent less in body weight to 24 weeks of age and ten per cent less to 36 weeks. Birds reared under the decreasing lighting regime reached sexual maturity at the same age as those reared under increasing lighting, ate five per cent more feed during the rearing and laying periods and gained five per cent more in body weight to 24 weeks. The mean weight of eggs laid between 24 and 34 weeks of age from pullets subjected concurrently to decreasing lighting and restricted feeding was approximately two grams heavier than that of the other three treatment combinations. Mean egg weight was one gram greater in the restricted than in the full fed group, although the difference was not statistically significant. Laying mortality was lower in the restricted fed group than in the full fed group.

Growth rate and growth composition of artificially reared piglets from specific pathogen free sows

1993 ◽  
Vol 56 (2) ◽  
pp. 217-223 ◽  
Author(s):  
M. W. A. Verstegen ◽  
W. van der Hel ◽  
F. J. M. Pijls
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Nitrogen Balance ◽  
Environmental Temperature ◽  
Specific Pathogen Free ◽  
Protein Deposition ◽  
Daily Rate ◽  
Specific Pathogen ◽  
Balance Technique ◽  
The Mean

AbstractHeat production, energy and nitrogen balances of artificially reared piglets from specific pathogen free sows, housed in a respiratory chamber, were measured over five successive periods of 7 days each from 4 to 39 days of age. The experiment was carried out at an environmental temperature decreasing from 33 to 27°C. The mean weight increased from 1·5 (at day 4) to 11·9 kg (at day 39). Daily rate of gain increased from about 100 g in periods 1 and 2 to 502 g per piglet in the fifth period.Daily protein deposition, as measured via nitrogen balance, increased from 17 to 96 g; fat deposition increased from about 0 to 100 g. Body composition at the start and end was determined by a comparative slaughter technique. Protein and fat content had a high correlation coefficient with body weight (R2 = 0·69 and 0·89, respectively). At birth these values were much lower, 0·24 and 0·01 for protein and fat, respectively.Nitrogen balance compared with slaughter technique led to an overestimation for protein deposition of proportionately 0·07. Fat gain measured from slaughter was proportionately 0·08 lower than that calculated from energy balance.Ratio of gain estimated from protein and fat gain with the balance technique relative to that measured ranged between 0·93 to 1·15 in various periods.

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