Effects of reduction of litter size on subsequent growth and reproductive performance in mice

1973 ◽  
Vol 16 (1) ◽  
pp. 1-6 ◽  
Author(s):  
David Machin ◽  
Sheila Page
Keyword(s):  
Litter Size ◽  
Reproductive Performance ◽  
Size Effects ◽  
Subsequent Growth

SUMMARYLitters that contained at least 13 mice were reduced at birth to 12, 8, or 4; and any natural litters of these sizes were also kept. The growth of these mice and their subsequent reproductive performance when mated at 6,10 and 14 weeks of age were recorded. All their offspring were weighed at weaning (4 weeks); some were weighed also at 12 days and 6 weeks of age.The amount of milk supplied was not fully adjusted to the size of the litters. This had lasting effects so that, even at the oldest age for mating, the mice from the small litters were noticeably the heaviest. Litter size effects extended to significant differences in fertility (numbers born) and less obviously to the numbers weaned. The mice that were mated at 14 weeks were the most fertile. There was little to distinguish the mice from natural and reduced litters of the same size.Small differences in weights of the offspring at 12 days, 4 weeks and 6 weeks of age bore no consistent relation to these factors.

THE ACCUMULATIVE EFFECT OF FINNSHEEP BREEDING IN CROSSBREEDING SCHEMES: REPRODUCTIVE PERFORMANCE

1988 ◽  
Vol 68 (1) ◽  
pp. 69-81 ◽  
Author(s):  
MOHAMED H. FAHMY ◽  
JACQUES J. DUFOUR
Keyword(s):  
Body Weight ◽  
Mortality Rate ◽  
Key Words ◽  
Litter Size ◽  
Reproductive Performance ◽  
Conception Rate ◽  
Ovulation Rate ◽  
Genetic Groups ◽  
Linear Regressions ◽  
Size At Birth

Reproductive performance and body weight were studied on 361 ewes, representing Finnsheep (F), DLS (a population of 1/2 Dorset, 1/4 Leicester, 1/4 Suffolk) and seven combinations ranging from 1/8 to 7/8 Finnsheep breeding. Conception rate in yearlings was 61.5% for DLS compared to 89.0% for F with the crosses being intermediate. Conception rate in older ewes was similar in the different genetic groups (avg. 94%). Ovulation rate and litter size at birth of DLS ewes were 1.72 and 1.44 lambs, which was less than half those of F ewes (3.51 and 2.86 lambs, respectively). Both traits increased progressively with an increase in F breeding in crosses and with advances in age. DLS ewes weaned 1.22 lambs compared to 2.03 lambs for F ewes and 1.84 lambs for 4/8 F ewes. The heaviest litters at weaning (31.7 kg) were raised by 4/8 F ewes, followed by 7/8 F (30.8 kg) while those raised by DLS ewes weighed 23.0 kg and F ewes 29.1 kg. Percentage of ova lost per ewe mated averaged 24% and ranged between 18% (DLS and 1/8 F) and 29% (6/8 F). About 3.6% of lambs were born dead and a further 13.8% died before weaning. Preweaning mortality rate was highest in F (22.9%) and lowest in 3/8 F (9.4%). Average kilograms of lambs weaned per ewe exposed was highest in 4/8 F (27.6 kg) followed by F (26.0 kg), whereas that of DLS was the lowest at 18.1 kg. The 4/8 F cross showed 25% heterosis in kg of lambs weaned per ewe exposed and 52.5% increase over DLS. Significant positive linear regressions were calculated for ovulation rate, litter size and preweaning mortality rate on proportion of Finnsheep breeding in crosses. The relation was quadratic for percent ova lost and lamb mortality at weaning. Yearling DLS females weighted 36 kg compared to 44 kg for F yearlings. However, at 5 yr of age DLS ewes weighed 62 kg, 5 kg heavier than F ewes. The heaviest ewes at all ages were the 4/8 F (45 kg at 1 yr, 65 kg at 5 yr). Key words: Reproduction, DLS sheep, Finnsheep, crossbreeding, heterosis, repeatabilities

scholarly journals Effects of cooling on the reproductive performance of gilts

2016 ◽  
Vol 20 (2) ◽  
pp. 357-361
Author(s):  
J.O. Oyedeji ◽  
G.O. Imagbenikaro
Keyword(s):  
Birth Weight ◽  
Litter Size ◽  
Reproductive Performance ◽  
Feed Intake ◽  
Cooling System ◽  
Large White ◽  
Feed Cost ◽  
Randomized Design ◽  
Significant Difference ◽  
Level Of Significance

The study examined the effect of cooling on the reproductive performance of gilts using 27 Large White Experimental Gilts on a Completely Randomized Design (CRD) with 3 systems of cooling, namely Wallow Cooling (WC), Sprinkler Cooling (SC) and Zero Cooling (ZC). Gilts were weighed at the commencement of the experiment and thereafter fed ad libitum from service to farrowing. Feed intake till farrow, feed cost, gilt weight at farrow, date of farrow, litter size and weight were recorded. The feed/piglet weight, feed intake/litter, feed cost/litter and birth weight/piglet were derived. The results showed that feed intake per litter and feed per piglet weight were highest for gilts placed on WC(P< 0.05), followed by SC and least for sow placed on ZC; gilt weight before farrow was highest for sow placed on SC (69.78±0.92), followed by ZC (69.33±0.94) and least for gilts placed on WC (67.33±0.87); litter sizes of gilts placed under the WC and SC systems were similar (5.6±0.41) while that under the ZC system was comparatively smaller (5.4±0.40);while the date of farrow was lowest in the ZC system (113.8±0.32) followed by SC (114.0±0.33) and highest under the WC (114.1±0.33). However, the feed intake per litter, feed per piglet weight, litter sizes of gilts, birth weight per piglet of gilts and the average date of farrow among gilts placed on WC, SC and ZC were not statistically different at 5% level of significance. Though, there is no significant difference in the performance among gilts placed on WC, SC and ZC, temperature regulation through provision of efficient cooling system in piggery would help to increase litter size, improve feed intake per litter and reduce the average cost of feeding gilt per day in maximizing reproductive performances in pigs.Keywords: Cooling, gilts, service, farrow, piggery, litter size, piglet and birth weight

scholarly journals The influence of adding estradiol to semen on reproductive performance of sows

1991 ◽  
Vol 71 (2) ◽  
pp. 589-591 ◽  
Author(s):  
R. N. Kirkwood ◽  
P. A. Thacker
Keyword(s):  
Key Words ◽  
Litter Size ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Pregnancy Rates ◽  
And Control ◽  
Estradiol 17Β

One hundred gilts and one hundred mixed-parity sows of Yorkshire and Landrace breeding were inseminated with semen with or without an additional 10 μg estradiol-17β. Pregnancy rates of gilts receiving estradiol-supplemented and control semen were 90 and 79%, respectively (P < 0.09). The estradiol supplementation of semen did not improve the pregnancy rates or litter size in sows. Key words: Swine, artificial insemination, estradiol

scholarly journals Effect of parity on reproductive performance sows of different breeds

2020 ◽  
Vol 50 (3) ◽  
pp. 434-441
Author(s):  
R. Klimas ◽  
A. Klimienė ◽  
W. Sobotka ◽  
W. Kozera ◽  
P. Matusevičius
Keyword(s):  
Survival Rate ◽  
Litter Size ◽  
Reproductive Performance ◽  
Weaned Piglets ◽  
Large White ◽  
Litter Weight ◽  
Piglet Survival

The aim of this study was to determine the effect of parity on reproductive performance by sows of different breeds. The sows were raised on three farms, and had seven or more litters of not fewer than seven piglets. A total of 1511 litters from various parities of Lithuanian White (N =721), Large White (N = 162) and Landrace (N = 628) sows were contained in the data that were used in this study. Multiparous sows had larger litters than primiparous sows. Piglet survival rate declined from parity 7. An increase in litter size was observed until parity 5 in Large White and until parity 6 in improved Lithuanian White (P <0.05). In comparison with parity 1, Landrace sows up to parity 5 showed not only increased prolificacy, but also increased number and litter weight of piglets at 21 days old, and the number and litter weight of weaned piglets (P <0.01). The current findings indicate that sows of these breeds can be used effectively in breeding herds until parity 5 and parity 6.Keywords: Landrace, Large White, Lithuanian White, litter size

Effects of nutrition and photoperiod on reproductive physiology of Microtus montanus

1965 ◽  
Vol 208 (4) ◽  
pp. 633-638 ◽  
Author(s):  
Aelita J. Pinter ◽  
Norman C. Negus
Keyword(s):  
Dietary Supplement ◽  
Litter Size ◽  
Reproductive Performance ◽  
Wheat Plant ◽  
Reproductive Physiology ◽  
The Other ◽  
Active Principle ◽  
Microtus Montanus ◽  
Artificial Illumination ◽  
Group D

A total of 140 pairs (one male, one female) of known-age virgin Microtus montanus was used in two experiments lasting 18 weeks each. Pairs were divided into two groups, one placed under 18 hr, the other under 6 hr of artificial illumination daily. Under each of the two photoperiods, half of the pairs received a dietary supplement of sprouted wheat every 3 days (G), the other half every 15 days (D). The G groups produced significantly more litters and offspring than did the D groups. Irrespective of diet, mean litter size was significantly larger under 18-hr than under 6-hr illumination. Any superiority in reproductive performance due to diet could be attributed solely to frequent (G) supplementation with sprouted wheat. "Plant estrogens" are tentatively postulated as the active principle. Diet and photoperiod interact in their influence on reproductive physiology (G-18 was the most productive group, D-6 the least productive).

The influence of purified porcine relaxin on the reproductive performance of sows following artificial insemination with fresh or frozen semen

1991 ◽  
Vol 71 (1) ◽  
pp. 237-239 ◽  
Author(s):  
P. A. Thacker ◽  
A. D. Gooneratne ◽  
R. N. Kirkwood
Keyword(s):  
Key Words ◽  
Pregnancy Rate ◽  
Litter Size ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Pregnancy Rates ◽  
Frozen Semen

Pregnancy rates and litter sizes following insemination of sows with fresh-extended and frozen-thawed semen averaged 71 vs. 53% and 10.6 vs. 4.4, respectively, and was not affected by the addition of 12.5 μg relaxin to semen. These results indicate no relaxin mediated effect on either pregnancy rate or litter size when sows are artificially inseminated with relaxin-supplemented semen. Key words: Artificial insemination, relaxin, sows

Breeding Australian crossbred ewes with Arabian fat-tailed rams for intensive lamb production

1996 ◽  
Vol 36 (1) ◽  
pp. 31
Author(s):  
RC Malik ◽  
MA Razzaque ◽  
S Abbas ◽  
T Al-Mutawa ◽  
N Al-Khozam
Keyword(s):  
Birth Weight ◽  
Litter Size ◽  
Reproductive Performance ◽  
Average Daily Gain ◽  
Survival Rates ◽  
Intensive Management ◽  
Season Of Birth ◽  
Genetic Groups ◽  
Sources Of Variation ◽  
Daily Gain

The reproductive performance under intensive management of Border Leicester x Merino (BLM), Dorset x Merino (DM), and Suffolk x Merino (SM) ewes imported from Australia, and local fat-tailed Naeemi (N) ewes mated to N rams was studied. Progeny performance for birth and weaning weights, average daily gain (ADG) and preweaning survival was also evaluated. BLM ewes showed the highest reproductive performance. They produced and weaned (at 8 weeks) significantly more lambs (P<0.05) than any of the other ewe genotypes. The reproductive performance of the BLM, N, DM and SM ewes, mated twice, 8 months apart, was 127, 85, 91 and 85 respectively for percentage of lambs born to ewes joined, 109, 72, 77 and 70 respectively for percentage of lambs weaned to ewes joined, and 17.8, 13.5, 12.1 and 11.6 kg respectively of lamb weaned per ewe joined over the period of 13 months from the first joining until last lambs weaned. The effect of season on ewe reproduction was significant. Birth weight was not influenced by genotype or season but did change significantly with litter size. Genetic group, litter size, season of birth and birth weight were significant sources of variation in the ADG and weaning weight of the lamb. N x BLM lambs were weaned at significantly heavier weights than lambs of the remaining 3 groups. Season of birth and birth weight also significantly affected preweaning lamb survival. About 86% of the lambs born alive were weaned with little difference between genetic groups in survival rates.

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