scholarly journals 17 Effects of birth traits, physical or fenceline boar exposure and group size on pubertal measures and lifetime fertility of replacement gilts

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 12-12
Author(s):  
Robert V Knox ◽  
Ashley Daniel ◽  
Jenny Patterson ◽  
Lidia S Arend ◽  
George Foxcroft

Abstract In experiment 1, prepubertal gilts with (n = 264) and without (n = 43) birth records received Fenceline (FBE) or Physical (PBE) Boar Exposure (BE) in a Boar Exposure Area (BEAR). At 185 d of age, gilts (13/pen) received BE for 15 min/d for 3 wk. At the start of Week 3, anestrual gilts received PG600 or no-PG600 (Control). At estrus, females were moved into stalls and inseminated at 2nd heat. Gilts born in larger litters were lighter (r = -0.26) while heavier pigs grew faster to puberty (r = 0.25). PBE increased estrus in Week 1 (38%) over FBE (28%). In Week 3, PBE-PG600 increased estrus (79.9%) compared with PBE- Control (36.2%), while FBE-PG600 and Control did not differ (52.7 vs. 42.5%). By 6 wk, estrus tended to be greater (P < 0.08) for PBE (91.2%) than FBE (83.2%). Reduced fertility associated with: 1) small birth litter; 2) heaviest birthweight; 3) slower growth rate; 4) delayed puberty and age at 1st service; and 5) abnormal estrus interval. Experiment 2 tested the pubertal response to PBE or FBE with 10 or 20 gilts/pen. Gilts (n = 180) at 168 d with 1.8 m2 floor space received BE once/d for 15 min for 1–3 wk. At the start of Week 3, anestrual gilts received PG600. Estrus in Week 1 (7.3%) did not differ, but a BE x Pen effect occurred in Week 2 (estrus range: 15–34%). In Week 3, PG600 increased estrus (P < 0.03) in Pens of 10 (83.7%) compared to Pens of 20 (64.1%). BE method had no effect and Pens of 10 had greater estrus (P = 0.05) than Pens of 20 (88.3 vs 75.8%). These results indicated that use of PBE, a BEAR, smaller group size, and PG600 can be used in combinations to enhance puberty induction. Birth and pubertal measures influenced service and farrowing rate, litter size, and age at removal.

2019 ◽  
Vol 4 (1) ◽  
pp. 299-306
Author(s):  
Stuart R Callahan ◽  
Amanda J Cross ◽  
Ashley E DeDecker ◽  
Merlin D Lindemann ◽  
Mark J Estienne

Abstract We previously reported that reduced floor space allowance caused by increasing the number of gilts per pen decreased growth and affected blood chemistry and immunology. The current objective was to determine effects of nursery group-size-floor space allowance on future litter sizes and retention in the breeding herd through three parities in sows. A 3 × 3 factorial arrangement of treatments was employed with 2,537 gilts classified as large (6.92 ± 0.06 kg), medium (5.60 ± 0.06 kg), or small (4.42 ± 0.06 kg), and placed in nursery pens of 14, 11, or 8 pigs to allow 0.15, 0.19, or 0.27 m2 floor space/pig, respectively. After the nursery and grow-finish periods, 1,453 gilts selected for breeding were relocated to one of 11 sow farms. Total litter size and pigs born alive increased (P &lt; 0.01) with increasing parity and total litter size was 12.94, 13.28, and 13.99 (SE = 0.13) and pigs born alive was 12.21, 12.64, and 13.23 (SE = 0.11) for Parities 1, 2, and 3, respectively. There was a tendency (P = 0.08) for a quadratic relationship of group-size-floor space allowance and total litter size (13.39, 13.54, and 13.27 [SE = 0.13] for gilts allowed 0.15, 0.19, or 0.27 m2 floor space/pig, respectively). A linear effect of size of pig at weaning (P = 0.03) on pigs born dead was detected and was 0.64, 0.75, and 0.75, for small, medium, and large size pigs, respectively. There was no effect of group-size-floor space allowance on the percentages of gilts completing zero (P = 0.36), one (P = 0.35), two (P = 0.32), or three (P = 0.50) parities. In contrast, the percentage of small gilts that failed to complete one parity was greater (P &lt; 0.05) and the percentage completing one parity (P &lt; 0.05) was less than for either large or medium gilts. Abortion rate was greater (P &lt; 0.01) in gilts classified as small (2.51%) or medium (1.36%) at weaning compared with those classified as large (0.20%). Size at weaning did not affect the proportion of gilts completing two (P = 0.88) or three (P = 0.72) parities. Group-size-floor space allowance during the nursery phase of production did not have remarkable effects on future litter sizes or retention in sows. Likewise, size of pig at weaning did not affect litter size and pigs born alive. Compared with larger pigs, however, more pigs classified as small at weaning and entering the breeding herd did not complete a parity and displayed a greater abortion rate.


2018 ◽  
Vol 58 (11) ◽  
pp. 2029 ◽  
Author(s):  
F. De Rensis ◽  
C. Mazzoni ◽  
R. Saleri ◽  
A. Scollo ◽  
K. J. Plush ◽  
...  

The objective of the present study was to compare two common durations of altrenogest (ALT) feeding during different periods of the year on the fertility of gilts after ALT withdrawal. During a 12-month period gilt replacements that were assumed to be cyclic were subjected to oestrus synchronisation with 15 mg/day ALT administered for 18 days (ALT-18; n = 268) or 14 days (ALT-14; n = 153) whereas 275 non-treated gilts served as controls. Fewer ALT-14 than ALT-18 gilts expressed oestrus by 7 days after last ALT treatment (79.1% vs 88.8%; P < 0.05). Farrowing rate was lower (P < 0.05) for ALT-14 than for the other groups (81%, 91% and 92% for ALT-14, ALT-18, and Control, respectively) but farrowing rates were not affected by time of year. Control litter sizes were not different from ALT-14 except during September to November when Control litter sizes were larger than either ALT treatments (13.6 ± 0.33, 12.3 ± 0.65 and 12.7 ± 0.39 for Control, ALT-14 and ALT-18, respectively; P < 0.05). The ALT-18 gilts had larger litter sizes during January to August. The present data suggest that the appropriate duration of ALT feeding to synchronise oestrus in gilts is 18 days.


2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 10-11
Author(s):  
Mark J Estienne ◽  
Stuart Callahan ◽  
Amanda Cross ◽  
Ashley DeDecker ◽  
Merlin D Lindemann

Abstract We previously reported that crowding in the nursery decreased growth rate and affected blood chemistry and hematology measures in gilts. In the current experiment, weanling gilts were allowed decreased floor space in the nursery to determine effects of crowding on their future litter sizes and retention as sows. Of 2,537 gilts classified at weaning as large (6.92 kg), medium (4.42 kg), or small (5.60 kg) and reared in nursery pens of 14, 11, or 8 pigs (to allow 0.15, 0.19, or 0.27 m2 floor space/pig, respectively), 1,453 gilts were selected for breeding and distributed among 11 sow farms. As expected, total litter size (12.94, 13.28, and 13.99; SE = 0.13) and born alive (12.21, 12.64, and 13.23; SE = 0.11) increased (P < 0.01) from parity one to three. A tendency (P = 0.08) existed for a quadratic relationship between space and total litter size [13.39, 13.54, and 13.27 (SE = 0.13) for gilts allowed 0.15, 0.19, or 0.27 m2 floor space/pig, respectively]. A linear effect of pig size (P = 0.03) on stillborns was detected (0.64, 0.75, and 0.75, for small, medium, and large, respectively). There was no effect of space on the percentages of gilts completing zero (P = 0.36), one (P = 0.35), two (P = 0.32) or three (P = 0.50) parities. However, the percentage of small gilts completing zero parities was greater (P < 0.01), and the percentage completing one parity was less (P < 0.01) than for large or medium gilts. Abortion rate was greater (P < 0.01) in gilts classified as small (2.51%) or medium (1.36%) compared with large (0.20%). Floor space allowed in the nursery did not remarkably affect litter sizes or retention through three parities in sows. Compared with larger pigs, however, more small pigs entering the breeding herd did not complete a parity and displayed a greater abortion rate.


2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 3-4
Author(s):  
Heath M Harper ◽  
Rachel Schmitt ◽  
Michael Ellis ◽  
Caleb M Shull ◽  
Clint R Schwab

Abstract It is common commercial practice in wean-to-finish facilities to pin pigs in large groups during the nursery phase. The effect of overstocking on wean-to-finish performance has been studied; however, there is limited information on the effect of group size during the nursery period on overall growth performance, particularly in PRRS positive populations. This study was carried out using a RCBD (blocking factor date of start of test) to evaluate the effect of 3 nursery group size treatments (61, 79, and 96 pigs/pen) on wean-to-finish growth performance (from 6.0 ± 0.10 to 122.2 ±0.8kg BW) in a PRRS positive population. During the 7-wk nursery period, when the group-size treatments were applied, pigs were housed in mixed-sex pens; floor space for all treatments was 2.4ft2/pig. After the nursery period, pigs on all treatments were housed in groups of 34 at a floor space of 6.5ft2/pig. A total of 3,672 pigs in 12 replicates were used. Pen of pigs was the experimental unit; data were analyzed using PROC MIXED of SAS (SAS Inst. Inc., Cary, NC) with the model including fixed effect of group size treatment and random effects of block and replicate. During the period from weaning to wk 7 post-weaning, when the group size treatments were applied, growth rate and live weight was lower (P < 0.05) for the largest group size (96 pigs) than for the 2 smaller group sizes (61 and 79 pigs). However, subsequently from wk 7 to end of test and for the overall wean-to-finish growth performance was similar (P > 0.05) for the 3 group size treatments. This study showed that group size (at the same floor space) had an effect on growth performance in the nursery period but had no effect on overall wean-to-finish growth performance in PRRS positive pigs.


2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 123-123
Author(s):  
Lidia S Arend ◽  
Robert V Knox ◽  
Amanda M Minton ◽  
Clint R Schwab ◽  
Caleb M Shull ◽  
...  

Abstract Increasing the distribution of semen from genetically superior sires accelerates the rate of improvement of economically important traits. Using a single fixed time post-cervical AI (SFTI) with ovulation control, the number of inseminations per ejaculate can be doubled. The objective of the study was to determine whether ovarian ultrasound could help identify parity (P1, 2, 3-6, ≥ 7) and seasonal (May-Jun, Jul-Aug, Sep-Oct) effects on fertility following induced ovulation and SFTI. Sows received OvuGel® (n = 914) on Days 3-5 after weaning and a SFTI 24 h later. Control sows (n = 881) that expressed estrus on Days 3-6 received a post-cervical AI on each day standing. Ovaries of a sub-population of sows (n = 436) were scanned by ultrasound to assess follicle size and insemination to ovulation interval. Interval from insemination to ovulation > 24 h tended (P = 0.09) to reduce farrowing rate (FR, 74.1 ± 2.8%) compared to inseminations £ 24 h (83.4 ± 2.8%), regardless of treatment. In addition, sows that ovulated by Day 6 after weaning had greater (P = 0.03) total born (TB, 12.9 ± 0.5) than those ovulating ≥ 7 d (11.5 ± 0.5). Follicle number (16.3 ± 0.7) and size (7.0 ± 0.5 mm) on Day 4 did not differ between treatments. OvuGel increased (P = 0.002) the proportion of sows ovulating (88.9%) versus Controls (78.6%), but for both treatments, fewer P1 sows ovulated (75.0%) when compared to P3-6 (90.4%). Treatments did not differ in FR (78.5%), but seasonal interactions were observed (P = 0.05), most notably in Sep-Oct. Parity affected FR (P = 0.02), and was lower in P1 (66.1%) compared to 3 P2 (82.2%). Also, OvuGel and Control did not differ in TB (13.0) but parity ≥ 7 had the lowest TB (11.8) compared to younger parity females. In summary, OvuGel increased the proportion of sows ovulating by 10.3%, resulting in similar FR and TB compared to Control sows inseminated multiple times based on estrus.


2017 ◽  
Vol 95 (1) ◽  
pp. 201
Author(s):  
S. R. Callahan ◽  
A. J. Cross ◽  
A. E. DeDecker ◽  
M. D. Lindemann ◽  
M. J. Estienne

1999 ◽  
Vol 1999 ◽  
pp. 176-176
Author(s):  
A.R. Peters ◽  
L.A. Dwyer ◽  
A. Dawson ◽  
P.A. Canham ◽  
J.D. Mackinnon

The problem of seasonal infertility in pigs has been recognised for many years. The infertility complex can may be manifested by increased returns to service, prolonged weaning to oestrus intervals and decreased litter size. The purpose of this trial was to evaluate the effects of Buserelin treatment on fertility in sows and gilts during the seasonally infertile period.A total of 1231 mixed parity sows and gilts from five outdoor herds in East Anglia were randomly assigned to one of three treatment groups. Any sows not presented for service at first post weaning oestrus were excluded. All sows and gilts judged to be in adequate health and condition to be kept in a commercial breeding herd were included. Group C sows and gilts were given no treatment. Group R1 sows and gilts were injected i.m. with 8μg Buserelin (2.0ml Receptal; Hoechst Roussel Vet UK Ltd) on the day of service.


Genetics ◽  
1966 ◽  
Vol 54 (6) ◽  
pp. 1423-1429 ◽  
Author(s):  
G W Rahnefeld ◽  
R E Comstock ◽  
Madho Singh ◽  
S R NaPuket

1993 ◽  
Vol 57 (2) ◽  
pp. 332-334 ◽  
Author(s):  
A. Blasco ◽  
E. Gómez

Two synthetic lines of rabbits were used in the experiment. Line V, selected on litter size, and line R, selected on growth rate. Ninety-six animals were randomly collected from 48 litters, taking a male and a female each time. Richards and Gompertz growth curves were fitted. Sexual dimorphism appeared in the line V but not in the R. Values for b and k were similar in all curves. Maximum growth rate took place in weeks 7 to 8. A break due to weaning could be observed in weeks 4 to 5. Although there is a remarkable similarity of the values of all the parameters using data from the first 20 weeks only, the higher standard errors on adult weight would make 30 weeks the preferable time to take data for live-weight growth curves.


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