EFFECTS OF A COLD ENVIRONMENT AND GROWTH RATE ON REPRODUCTIVE EFFICIENCY IN GILTS

1974 ◽  
Vol 54 (3) ◽  
pp. 287-292 ◽  
Author(s):  
G. W. DYCK
Keyword(s):  
Growth Rate ◽  
Pregnancy Rate ◽  
Ovulation Rate ◽  
Feed Consumption ◽  
Reproductive Efficiency ◽  
Breeding Period ◽  
Corpora Lutea ◽  
Cold Environment ◽  
Fetal Survival ◽  
Moderate Growth

The effects of a cold environment and growth rate on reproductive efficiency at 60 days of pregnancy were studied in 96 Lacombe gilts. On each of two consecutive years, four Lacombe boars were assigned to 48 gilts for a 42-day breeding period commencing 6 December. The animals were individually housed in a heated piggery (10–15 C) and in outside lots with a wooden cabin for shelter (mean maximum −12 C, mean minimum −22 C). The gilts were fed at a level to provide for minimum growth (0.03 kg/day) and moderate growth (0.36 kg/day). Gilts housed in the piggery were fed 1.5 and 3.0 kg/day, whereas the gilts housed outside had their feed consumption increased by a maximum of 1 kg/day to maintain similar growth rates. The cold environment had no effect on ovulation rate (12.9), fetal survival (71%), fetal weight (106 g), uterine weight (1,486 g) and ovarian weight (14.4 g) as measured at 60 days of pregnancy. The mean weight of the corpora lutea was greater for gilts housed in the outside lots (498 vs. 459 g). Gilts with the moderate growth rate had a greater ovulation rate (13.4 vs. 12.3, P < 0.05), lower fetal survival (65.6 vs. 77.7%, P < 0.01), heavier fetuses (112.6 vs. 98.0 g, P < 0.01), heavier uteri (1,556 vs. 1,391 g, P < 0.05), heavier ovaries (15.4 vs. 13.1 g, P < 0.01), and heavier corpora lutea (500 vs. 448 mg, P < 0.01) than the gilts with minimum growth rate. Pregnancy rate, as a percentage of the gilts on the experiment that became pregnant, was similar for the two winter environments (piggery, 77.1%; outside lots, 72.9%). Pregnancy rate was greater for the gilts with the moderate growth rate (85.4 vs. 64.6%, P < 0.05).

PROGESTERONE AND LUTEINIZING HORMONE CONCENTRATION IN SERUM OF PREGNANT GILTS ON DIFFERENT LEVELS OF FEED CONSUMPTION

1980 ◽  
Vol 60 (4) ◽  
pp. 877-884 ◽  
Author(s):  
G. W. DYCK ◽  
W. M. PALMER ◽  
S. SIMARAKS
Keyword(s):  
Luteinizing Hormone ◽  
Feed Consumption ◽  
Blood Collection ◽  
Corpora Lutea ◽  
Serum Progesterone ◽  
Treatment Groups ◽  
Fetal Survival ◽  
Serum Lh ◽  
Luteinizing Hormone Concentration ◽  
Collection Period

Blood serum progesterone (P) and luteinizing hormone (LH) were determined in 31 Lacombe gilts at a 3- to 4-day interval from 10 to 56 days of pregnancy. They were fed 1.50 (L), 2.25 (M) or 3.00 (H) kg of a 16% protein diet/day and had average daily gains of 0.16 ± 0.02 (SE), 0.36 ± 0.02 and 0.60 ± 0.02 kg/day, respectively. All gilts were slaughtered between 59 and 61 days of pregnancy. The treatments had no effect on the number of corpora lutea (13.9 ± 0.4 CL), number of fetuses (10.8 ± 0.6), fetal survival (78.3 ± 3.7%) or mean fetal weight (122 ± 3 g). The gilts on the H level of feeding had heavier (P < 0.05) ovaries (18.4 ± 0.8 g) than those of the L (15.6 ± 0.7 g) or M (15.6 ± 0.8 g) treatment groups. Serum P concentration declined during the blood collection period (b = −0.12, −0.06 and −0.09 for the L, M and H groups, respectively). Serum P concentrations also were different (P < 0.01) for each treatment group (L, 16.7 ± 0.3; M, 13.8 ± 0.03; and H, 11.8 ± 0.3 ng/mL). The serum LH concentration was greater (P < 0.05) for the M gilts (0.63 ± 0.05 ng/mL) than for the L (0.37 ± 0.04 ng/mL) or H (0.47 ± 0.05 ng/mL) gilts. Significant correlations were observed among the number of fetuses, number of CL, ovarian weight and P for the L gilts, and the number of fetuses and CL for the M gilts. These results suggest that growth rate is a major contributor to differences in blood P and LH concentrations during pregnancy and that the animal adjusts its P and LH production to its specific requirements for the maintenance of pregnancy.

Effect of supplemental vitamin E during prepubertal development and early gestation on reproductive performance and nutrient metabolism in gilts

1993 ◽  
Vol 73 (3) ◽  
pp. 593-603
Author(s):  
R. R. Grandhi ◽  
M. W. Smith ◽  
M. Frigg ◽  
P. A. Thacker
Keyword(s):  
Vitamin E ◽  
Reproductive Traits ◽  
Ovulation Rate ◽  
Canola Meal ◽  
Corpora Lutea ◽  
Nutrient Metabolism ◽  
Serum Progesterone ◽  
Early Gestation ◽  
Fetal Survival ◽  
Supplemental Vitamin

The effect of feeding barley–canola-meal diets with supplemental vitamin E (dl-α-tocopherol acetate) at 0, 50 or 100 mg kg−1 on selected reproductive functions and nutrient absorption and retention was determined using Landrace × Yorkshire gilts. In exp. 1 (n = 150), gilts were fed three gestation diets, containing by analysis 23.5, 55.7 and 113.5 mg kg−1 of vitamin E respectively in diets 1, 2 and 3, from first estrus until approximately 33 or 65 d of gestation. Gilts fed diet 2 had a higher (P = 0.02) number of corpora lutea (13.8 ± 0.5 vs. 12.0 ± 0.5) at 65 d of gestation than the gilts fed diet 1. In exp. 2, gilts (n = 159) were fed three finisher diets, containing by analysis 17.6, 87.8 and 126.5 mg kg−1 of vitamin E, during prepubertal development period (59.2 ± 0.4 to 86.7 ± 0.8 kg body weight) and then switched (n = 150) to three gestation diets, containing 16.4, 54.2 and 103 mg kg−1 of vitamin E, until 58.7 ± 0.7 d of the gestation period. Gilts fed diet 3 had 16% lower (P < 0.05) anestrus than the gilts fed diet 1. The ovulation rate, number of live embryos and fetal survival were not influenced (P > 0.05) by supplemental vitamin E. The serum level of α-tocopherol was linearly increased (P < 0.01) by feeding supplemental vitamin E in both experiments. Feeding supplemental vitamin E had no consistent beneficial effect on serum progesterone or on the apparent absorption and retention of selected nutrients during the prepubertal and gestation periods. The results indicated that feeding supplemental vitamin E at above 1988 NAS–NRC recommended levels during prepubertal development and early gestation only slightly improved certain reproductive traits in gilts. Key words: Gilts, vitamin E, ovulation rate, fetal survival, metabolism

MAINTENANCE OF PREGNANCY RELATIVE TO THE PRESENCE OF FEW EMBRYOS IN THE RABBIT

1970 ◽  
Vol 48 (2) ◽  
pp. 243-249 ◽  
Author(s):  
C. E. ADAMS
Keyword(s):  
Pregnancy Rate ◽  
Follicle Stimulating Hormone ◽  
Uterine Horn ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
The Mean ◽  
Stimulating Hormone

SUMMARY Either one or two 60-h morulae were transferred to one uterine horn of Polish, Dutch or Strain A rabbits in which the mean number of ovulations was 4·3, 6·4 and 10·8. The pregnancy rate, as determined by palpation on day 10, varied from 45–65% (mean 53%) in recipients of one egg to 69–71% with two eggs. Only 20% of the does carrying one foetus maintained pregnancy to term compared with 87% of those with two implants. If pregnancy failed this usually occurred between days 15 and 20. In a further experiment, in which additional eggs were transferred to the contralateral horn, it was shown that all single conceptuses were inherently capable of surviving to term. It is concluded that irrespective of breed and ovulation rate, two conceptuses are normally required to prevent regression of corpora lutea on about day 17. Treatment with follicle-stimulating hormone in mid-pregnancy or removal of the barren uterine horn on day 13 failed to maintain pregnancies involving only one conceptus.

scholarly journals Evaluating the economic profit of reproductive performance through the integration of a dynamic programming model on a specific dairy farm

2020 ◽  
Vol 65 (No. 4) ◽  
pp. 124-134
Author(s):  
Lenka Krpálková ◽  
Niall O' Mahony ◽  
Anderson Carvalho ◽  
Sean Campbell ◽  
Joseph Walsh
Keyword(s):  
Dynamic Programming ◽  
Pregnancy Rate ◽  
Reproductive Performance ◽  
Programming Model ◽  
Dairy Farm ◽  
Sensitivity Analyses ◽  
Reproductive Efficiency ◽  
Breeding Period ◽  
Net Return ◽  
Market Values

The overall objective of this study was to improve the reproductive efficiency of lactating dairy cows and to improve the resulting total farm profit. The hypothesis is that a dairy farm can substantially improve its economic and environmental performance through increasing pregnancy rate, i.e. increasing the number of eligible cows that become pregnant for a given breeding period. This paper presents a tool which was designed with a view to comparing the reproductive efficiency. The tool was developed using dynamic programming in R (Shiny) and shows the changes in costs, revenues and net return projected for a given change in pregnancy rate. The model calculates from the first day in milk and stops when the last calf was born after successful insemination of each cow. Sensitivity analyses demonstrated that the economic return associated with reproductive performance is greatly affected by the input parameters and therefore real farm and market values are crucial. The average economic gain per percentage point of 21-d (21-day) pregnancy rate (PR) was 14.6 EUR per cow/year. The milk price showed the largest impact on the overall net return. A 10% increase in milk price increased the net return on average by 268 EUR (10% 21-d PR), 292 EUR (20% 21-d PR) and 299 EUR per cow/year (30% 21-d PR). Our study had the same set values of milk yield during lactations for all four evaluated farms and it was found that the milk income over feed cost increased with the reproductive performance in all evaluated farms on an individual cow level. Poor fertility means that cows spend longer producing lower amounts of less efficiently produced milk.

A note on attainment of puberty of september-born early-maturing ewe lambs in relation to level of nutrition

1991 ◽  
Vol 53 (3) ◽  
pp. 407-409 ◽  
Author(s):  
F. Forcada ◽  
J. A. Abecia ◽  
L. Zarazaga
Keyword(s):  
Sexual Activity ◽  
Breeding Season ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Ewe Lambs ◽  
Early Maturing ◽  
Age At Puberty

The attainment of puberty in September-born early-maturing ewe lambs was studied at Zaragoza (latitude 41° 40' N). Thirty twin Salz females were allocated to two groups receiving two nutrition levels after 3 months of age: high (500 g/day lucerne hay and 500 g/day concentrate) (H) and low (500 g/ day lucerne hay) (L). Oestrus was detected daily by aproned rams. Corpora lutea were counted after oestrus and plasma progesterone levels monitored each week.In the first breeding season (January to February) the percentage of females showing sexual activity (silent emulation or oestrus and ovulation) was higher in the H compared with the L group (67 and 20%; P < 0/05). Nonpubertal oestrus before the main breeding season was detected in 67% of animals. In the main breeding season and for H and L groups respectively, percentage of females showing silent ovulation before puberty was 67 and 33% and mean age at puberty extended to 319 (s.e. 4-8) and 314 (s.e. 3·7) days. Ovulation rate at puberty was 1·73 (s.e. 0·13) and 1·33 (s.e. 0·15) respectively (P < 0·05).

The effect of time of mating on ovulation rate and potential lambing rate of Greyface ewes

1979 ◽  
Vol 29 (2) ◽  
pp. 277-282 ◽  
Author(s):  
R. G. Gunn ◽  
J. M. Doney ◽  
W. F. Smith
Keyword(s):  
Body Condition ◽  
Body Condition Score ◽  
Ovulation Rate ◽  
Stress Factors ◽  
Corpora Lutea ◽  
Differential Group ◽  
Condition Score ◽  
Group Feeding ◽  
Lambing Rate

ABSTRACTOver 2 years, 104 Greyface ewes were mated at a synchronized oestrus either in early October or early November. From late September until slaughter at return to service or between 4 and 7 weeks after mating, ewes were fed to maintain their body condition score as previously adjusted by differential group feeding on grass. Ovulation rate and potential lambing rate were derived from counts of corpora lutea and viable embryos at slaughter. Both rates were higher in the early-mated ewes in comparable body condition. Stress factors were implicated as contributing to the decline in ovulation rate with time, while ewes which failed to hold to first mating were largely responsible for the decline in potential lambing rate.

Fertility in Cheviot ewes. 2. The effect of level of pre-mating nutrition on ovulation rate and early embryo mortality in North and South Country Cheviot ewes in moderately-good condition at mating

1979 ◽  
Vol 29 (1) ◽  
pp. 17-23 ◽  
Author(s):  
R. G. Gunn ◽  
J. M. Doney ◽  
W. F. Smith
Keyword(s):  
Food Intake ◽  
Good Condition ◽  
Early Embryo ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Restricted Feeding ◽  
Embryo Mortality ◽  
The North ◽  
Breed Difference ◽  
High Level

ABSTRACTIn two experiments over 2 years, 57 North Country Cheviot and 82 South Country Cheviot hill ewes were differentially group-fed indoors over a 2-month period to achieve either good or moderate body con- dition. Over 5 weeks prior to mating, ewes in good condition were brought down in condition by restricted feeding and ewes in mod- erate condition were raised in condition by a high level of feeding. The ewes were thus in moderately-good condition at mating. After mating, ewes were maintained in this condition until killed either on return to service or at 29 ± 8 days for counts of corpora lutea and viable embryos.Ovulation rate in each breed was positively related to the level of pre-mating food intake at the condition level studied. Embryo mortality, as ova loss, was not influenced overall by the level of pre-mating food intake but loss of multiple-shed ova was greater than that of single-shed ova in ewes which had been on restricted feeding before mating. Although a greater proportion of ewes in the North Country Cheviot breed were not pregnant at slaughter, this could not be identified as a breed difference since the breeds were studied in different years.

Genetic variation in net feed efficiency in Hereford cattle and its association with other production traits

1999 ◽  
Vol 1999 ◽  
pp. 47-47
Author(s):  
R.M. Herd ◽  
S.C. Bishop
Keyword(s):  
Growth Rate ◽  
Genetic Variation ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Genetic Correlations ◽  
Feed Consumption ◽  
Production Traits ◽  
Performance Measurements ◽  
Hereford Cattle ◽  
Rate Selection

Net feed efficiency refers to variation in feed consumption between animals net of requirements for maintenance and production, and may be measured as residual feed intake (RFI). Because RFI is independent of liveweight (LW) and growth rate, selection for improved net feed efficiency is likely to reduce feed intake with little change in growth. The purpose of this study was to establish whether there exists genetic variation in RFI in young British Hereford bulls, and to determine the phenotypic and genetic correlations of RFI with key production traits.The data consisted of performance measurements on 540 bull progeny of 154 British Hereford sires, collected over ten 200-day postweaning performance tests conducted between 1979 and 1988. The traits analysed were food intake (FI), 200 to 400-day daily gain (ADG), 400-day weight (W400), predicted carcass lean content (LEAN), lean growth rate (LGR), food conversion ratio (FI/ADG) and lean FCR (LFCR; FI/(ADG x LEAN), described by Bishop (1992).

scholarly journals Calving sub-season and reproductive efficiency of beef cows

2010 ◽  
Vol 39 (10) ◽  
pp. 2182-2186
Author(s):  
Cristiane Reinher ◽  
Júlio Otávio Jardim Barcellos ◽  
Vanessa Peripolli ◽  
Ênio Rosa Prates ◽  
Maria Eugênia Andrighetto Canozzi
Keyword(s):  
Pregnancy Rate ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Reproductive Efficiency ◽  
Climate Variations ◽  
Southern Brazil ◽  
Chi Square ◽  
Chi Square Test

It was evaluated in this work the effect of calving sub-season on the pregnancy rate of 7,726 multiparous Hereford beef cows grazing on natural pastures in southern Brazil, from 1994 to 2007. Calving sub-season periods were divided in 20-day intervals from August 12th to 31st; from September 1st to 20th; from September 21st to October 10th; from October 11th to 31st; from November 1st to 20th. Calving in each sub-season and pregnancy rate (PR) were analyzed by the Chi-square test. Overall means of each sub-season were 92.7% (from August 12th to 31st), 90.6% (from September 1st to 20th), 82.1% (from September 21st to October 10th), 77.7% (from October 11th to 31st), and 70.6% (from November 1st to 20th). Calving sub-season significantly influenced pregnancy rate. Cows which calved in the initial sub-season showed higher pregnancy rates than cows which calved from the fourth calving sub-season. However this difference did not occur in 1999 and in 2007 since calving rates did not statistically differ among the five sub-seasons. In 1998 and 2004, calving rates were lower and the effects of calving sub-season on pregnancy rates were higher, possibly due to climate variations. In general, pregnancy rate decreases as calving occurs later in the year, particularly in years when the weather adversely affects pasture growth.

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