The effect of age of purebred large white and landrace boars at time of service on herd performance

Author(s):  
M. J. H. Francis ◽  
J. T. Mercer

Practically, the effect of selection for growth and efficiency on breeding performance has been largely ignored in the past, despite changes in the age and weight of animals at puberty. It has been demonstrated that it is beneficial to delay service in gilts, both to improve their condition and allow them to complete more oestrous cycles prior to service. It seems likely that performance of boars might also be enhanced if they were worked later.This analysis was designed to examine the relationship between age and reproductive performance in the boar, with a view to developing guidelines for young boar management.

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 18-18
Author(s):  
Leticia P Sanglard ◽  
Felipe Hickmann ◽  
Yijian Huang ◽  
Kent A Gray ◽  
Daniel Linhares ◽  
...  

Abstract Immunoglobulin G antibody response, measured as sample-to-positive (S/P) ratio, to Porcine Reproductive and Respiratory Syndrome virus (PRRSV) has been proposed as an indicator trait for improved reproductive performance in PRRSV-infected purebred sows and PRRSV-vaccinated crossbred gilts. In this study, we investigated the genetic correlations (rg) of S/P ratio following a PRRSV outbreak and PRRSV-vaccination with performance in non-exposed and PRRSV-exposed sows. PRRSV outbreak phase was defined based on previously described methodologies after the detection of typical clinical signs of PRRSV infection. 541 Landrace sows had S/P ratio measured at ~54 days after the beginning of the PRRSV outbreak (S/Poutbreak), and 906 Landrace x Large White naïve F1 gilts had S/P ratio measured at ~50 days after vaccination with a commercial modified live PRRSV vaccine (S/PVx). 711 and 428 Landrace sows had reproductive performance recorded before and during the PRRSV outbreak, respectively. 811 vaccinated F1 animals had farrowing performance for up to 3 parities. All animals were genotyped for ~28K SNPs. The estimate of rg of S/Poutbreakwith S/PVx was high (rg±SE = 0.72±0.18). Estimates of rg of S/Poutbreak with reproductive performance in F1 sows were low to moderate, ranging from 0.05±0.23 (number stillborn) to 0.30±0.20 (total number born). Estimates of rg of S/PVxwith reproductive performance in non-infected purebred sows were moderate and favorable with number born alive (0.50±0.23), but low (0 to -0.11±0.23) with litter mortality traits. Estimates of rg of S/PVx were moderate and negative (-0.47±0.18) with the number of mummies in PRRSV-infected purebred sows and low with other traits (-0.29±0.18 for total number born to 0.05±0.18 for number stillborn). These results indicate that selection for antibody response following a PRRSV outbreak collected in purebred sows and to PRRSV vaccination collected in commercial crossbred gilts may increase litter size of non-infected and PRRSV-exposed purebred and commercial crossbred sows.


1985 ◽  
Vol 34 (3) ◽  
pp. 365-365
Author(s):  
R. GUEBLEZ ◽  
J. M. GESTIN ◽  
Geneviève LE HENAFF

1975 ◽  
Vol 20 (3) ◽  
pp. 401-406 ◽  
Author(s):  
D. J. A. Cole ◽  
M. A. Varley ◽  
P. E. Hughes

SUMMARYForty litters were weaned from their Landrace × Landrace × Large White dams at 2-day intervals to give a range of lactation lengths from 4 to 42 days. A significant (P<0·001) negative curvilinear relationship was observed between lactation length and the interval from weaning to first oestrus. This period was increased by 4·2 days with the reduction of lactation from 42 to 4 days. The relationship between lactation length and the interval from farrowing to remating was significant (P<0·001) and positively linear over the whole range of observations. A decrease of 1 day in lactation length reduced this interval by 0·91 days. Very short lactations were associated with reduced litter size at the following farrowing; sows weaned after lactation lengths between 4 and 21 days had an average litter size of 9–6 piglets born per litter in the next parity, whereas sows weaned following lactation lengths between 21 and 42 days had an average of 12·7 piglets born in the next parity (P<0·01).


2017 ◽  
Vol 45 (1) ◽  
pp. 6
Author(s):  
Jamil Elias Ghiggi Faccin ◽  
Fernanda Laskoski ◽  
Paulo Emílio Lesskiu ◽  
Aline Fernanda Lopes Paschoal ◽  
André Luiz Mallmann ◽  
...  

Background: Gilts represent the largest category (18-20%) of female pigs in a breeding herd. Under field conditions, the amplitude of growth rate and age at the first mating of gilts are remarkably higher than the recommendations made by the genetic companies. There are several studies that have considered the management of these animals starting from their introduction to the herd till the mating. It has been noted that the genetic selection constantly promotes evolution that may change certain traits of these animals. However, there is a lack of the studies that evaluate the management strategies suitable for the modern sows. This study, therefore, aimed to evaluate the effect of age and growth rate of gilts at the first mating on productive performance and retention rate until the third farrowing.Materials, Methods & Results: The study was performed in a gilt development unit (GDU) with a breeding stock capacity of 1000 females and a goal of 90 gilts mating per week. The groups were retrospectively created according to age (<210 d and ≥210 d) and the growth rate (GR; <700 g/d and ≥700 g/d) at the first mating with a 2 × 2 factorial design. A real-time ultrasound examination was performed at approximately 28 days after artificial insemination to detect pregnancy. Afterward, the productivity data over three parities of 703 females were collected and analyzed at 28 commercial farms of destination. The analyses were performed using SAS, with individual gilts as the experimental unit. The total number of piglets born and the age at the third parity were analyzed using the PROC MIXED. The number of estrus at breeding, weaning-to-estrus interval and the number of piglets in the previous farrowing were included as covariates in the model of total piglets born. The farrowing rate and retention rate until the third parity were considered as binary responses and analyzed using logistic regression (PROC GLIMMIX). The effects of age, GR, and their interaction were included as fixed effect in all analyses. There was no effect of age and GR and their interaction (P > 0.05) on farrowing rate after first, second, and third mating. The total number of piglets born in the three first farrowing and over three parities were not affected (P > 0.05) by the age and GR at first mating. The retention rate until the third farrowing of gilts inseminated with more than 210 days of age was approximately 7% greater than in the gilts mated younger; however, no statistical difference (P > 0.05) was detected. An effect of the age at the first mating was observed in the age to reach the third farrowing. Gilts mated with less than 210 and more than 210 days reached the third farrowing, respectively, at 604.5 ±1.9 and 625.1 ± 2.7 days of age (P < 0.001).Discussion: With a minimum GR of 550 g/d, 180 days of age, and at least 130 kg of weight, gilts are eligible to be inseminated without impairing their litter size, farrowing, and retention rate until the third parity. The gilts having modern genotypes can have a high stillbirth rate if bred with an excessive body weight. It is worth to consider that the gilts inseminated with > 700g/d did not present overweight in this study. The reproductive performance expressed by farrowing rate and piglets born and the longevity expressed by the retention rate from the first pregnancy until the third parturition were not impaired by the groups of age and GR in Large White × Landrace crossbred (Camborough 23®). In addition, gilts inseminated earlier than 210 days but having the minimum required weight resulted in less non-productive days for the breeding herd, which represents an important financial rate to the system.


1995 ◽  
Vol 61 (3) ◽  
pp. 561-564 ◽  
Author(s):  
J. B. Gaughan ◽  
R. D. A. Cameron ◽  
G. McL. Dryden ◽  
M. J. Josey

AbstractReproductive records from 1072 Large White sows (3589 litters) were used to examine the effect ofbackfat depth (Bd) and live weight (Lw) at selection on first litter and lifetime reproductive performance. The variables investigated included mating age, total piglets born, total born alive, piglet birth weight, number weaned, piglet weaning weight, weaning to remating period and number of litters produced. Using backfat depth, sows were categorized into three groups: L, 9 to 13 mm; M, 14 to 16 mm; and F, ≥17 mm. Bd had no significant effect (P > 0·05) on the measured traits for the sows grouped by fat at first parity. When lifetime reproductive data were analysed, the L group had fewer litters (P < 0·05), and weaned fewer pigs (P < 0·01) than either the M or F group. The birth weight for piglets from L sows were significantly higher (P < 0·05) than for piglets from the other groups. The data suggest that the reproductive performance of L sows is not as good as that of M or F sows.


2002 ◽  
Vol 82 (4) ◽  
pp. 503-506 ◽  
Author(s):  
D. H. Crews

Carcass data from purebred steer (n = 207) and heifer (n = 66) progeny of 15 Charolais sires with carcass expected progeny differences (EPD) were used to quantify the relationship between sire EPD and progeny phenotype for hot carcass weight, fat thickness, muscle area, marbling score, and percent lean yield. The model included six slaughter date × sex subclasses, the linear effect of age at harvest (434 ± 18 d), and the appropriate sire EPD for each trait of interest. Differences of the regression coefficients from their theoretical expectation of one were tested using general linear models procedures. Sire EPD was positively (P < 0.0001) associated with progeny performance for hot carcass weight, fat thickness, muscle area, marbling score, and percent lean yield. For all traits, the regression coefficients were not different (P > 0.27) from one. Regression coefficients were 1.16 ± 0.41 kg, 1.27 ± 0.27 mm, 1.23 ± 0.23 cm2, 1.26 ± 0.23 score, and 0.84 ± 0.19% for hot carcass weight, fat thickness, muscle area, marbling score, and percent lean yield, respectively. These results suggest that carcass EPD for hot carcass weight, fat thickness, muscle area, marbling score, and percent lean yield were related to progeny differences at or near theoretical expectations. Selection for carcass merit using appropriate EPD would be expected to be successful. Key words: Beef cattle, carcass, expected progeny difference


Animals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 794
Author(s):  
Damian Knecht ◽  
Sebastian Środoń ◽  
Katarzyna Czyż

The fatness and muscularity of Polish Landrace, Polish Large White gilts and sows and their hybrids were determined on the basis of ultrasound measurements in three consecutive parities, and then the relationship between these parameters and reproductive performance was established. Ultrasound measurements demonstrated the highest fat thickness in first parity and the highest fat area over LD muscle in hybrid gilts (PL × PLW). Pure-bred gilts were characterized by poorer muscularity. Fatness level affected the reproductive parameters of females in which the thickness of backfat in UP2 point was above 22.25 mm, the thickness of backfat in UP4 point was above 17.36 mm and the fat area over LD muscle was above 25.81 cm2. These females achieved better farrowing rates and higher numbers of born piglets. Decreased mortality, higher gains of piglets and higher body weight at weaning were observed, and the weaning to service interval was shortened in fatter females. Intramuscular fat content did not affect reproductive parameters. Muscularity negatively affected reproductive performance parameters, except gestation period. Too-high muscularity was related to the lowest levels of reproductive indices. The analysis of gilts and sows’ fatness and muscularity levels can help to predict their reproductive performance in the future and thus optimize production results.


GeroPsych ◽  
2020 ◽  
Vol 33 (4) ◽  
pp. 246-251
Author(s):  
Gozde Cetinkol ◽  
Gulbahar Bastug ◽  
E. Tugba Ozel Kizil

Abstract. Depression in older adults can be explained by Erikson’s theory on the conflict of ego integrity versus hopelessness. The study investigated the relationship between past acceptance, hopelessness, death anxiety, and depressive symptoms in 100 older (≥50 years) adults. The total Beck Hopelessness (BHS), Geriatric Depression (GDS), and Accepting the Past (ACPAST) subscale scores of the depressed group were higher, while the total Death Anxiety (DAS) and Reminiscing the Past (REM) subscale scores of both groups were similar. A regression analysis revealed that the BHS, DAS, and ACPAST predicted the GDS. Past acceptance seems to be important for ego integrity in older adults.


2019 ◽  
pp. 121-143
Author(s):  
Riccardo Resciniti ◽  
Federica De Vanna

The rise of e-commerce has brought considerable changes to the relationship between firms and consumers, especially within international business. Hence, understanding the use of such means for entering foreign markets has become critical for companies. However, the research on this issue is new and so it is important to evaluate what has been studied in the past. In this study, we conduct a systematic review of e-commerce and internationalisation studies to explicate how firms use e-commerce to enter new markets and to export. The studies are classified by theories and methods used in the literature. Moreover, we draw upon the internationalisation decision process (antecedents-modalities-consequences) to propose an integrative framework for understanding the role of e-commerce in internationalisation


Author(s):  
Nina TERREY ◽  
Sabine JUNGINGER

The relationship that exists between design, policies and governance is quite complex and presents academic researchers continuously with new opportunities to engage and explore aspects relevant to design management. Over the past years, we have witnessed how the earlier focus on developing policies for design has shifted to an interest in understanding the ways in which design contributes to policy-making and policy implementation. Research into policies for design has produced insights into how policy-making decisions can advance professional impact and opportunities for designers and the creative industries. This research looked into how design researchers and design practitioners themselves can benefit from specific policies that support design activities and create the space for emerging design processes.


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