A REVIEW ARTICLE ON NON-GENETIC FACTORS AFFECTING REPRODUCTIVE TRAITS IN SWINE

This review studies several factors affecting the reproductive performance of swine chiefly focusing on sow-related factors, which have significant economic importance. A sow’s productivity is determined by different reproductive attributes, including litter size, litter weight at weaning, farrowing rate, the return of oestrus, and many more. The increase in number of pigs born alive and weaned piglets per sow is an aim for swine husbandry.Various factors such as parity, housing, feed, gestation length, season, and temperature are considered in this paper. Sows of differing parities have performed differently.The performance was influenced by various feeding systems, comfort, spacing, aggressiveness, and disease transmission in the housing system. Feeding intake and nutrition uptake are directly connected with milk secretion as well as other traits. Season and temperature are correlated with feeding intake, time of puberty, hormonal production, and seasonal infertility.Scientists are globally working for productive breeds. However, the rearing of swine will necessitate the consideration of different non-genetic factors of their reproduction from an economicpoint of view.The goal of this study is to understand non-genetic factors that affect sow reproduction and to advise swine farmers on how to create a better environment for swine to improve productivity.

Impact of Sow Transition Diet and Genetic Line on Sow Reproduction Under Heat Stress Conditions

The objective was to evaluate a sow transition diet and genetic line for farrowing duration and sow lactation characteristics. One batch of second parity sows (n = 78) were farrowed at the NCDA Tidewater Research Station in July. Sows consisted of two genetic lines, one selected since 2012 for young age at puberty and the other selected for old age at puberty. From day 109 of gestation until day 3 of lactation, sows were fed either 2.73 kg of a corn-soy lactation diet (3322 Kcal ME/kg, 0.99% SID lysine) once per day or 1.36 kg twice per day of a transition diet (3489 Kcal/kg, 0.71 SID lysine). The transition diet contained 45% wheat middlings, 8% added soybean oil, 3000 FTU/kg of phytase and 500 ppm zinc sulfate. Continuous traits and categorical traits were analyzed in SAS using linear models and chi-square tests, respectively. Results showed sows fed the transition diet farrowed numerically faster (P = 0.18) than those receiving the lactation diet (3:04 vs. 3:47). Transition diet fed sows tended (P = 0.10) to have a shorter wean-to-estrus interval than sows fed the lactation diet (5.27 vs. 5.69 days). Sows from the young puberty genetic line tended (P = 0.07) to have a greater average daily feed intake during lactation when compared to old puberty line females (4.92 vs. 4.71 kg). Young puberty sows also had a greater (P = 0.03) percentage of females exhibiting estrus by day 7 after weaning when compared to the old puberty genetic line (80 vs. 57%). No differences (P = 0.39 to 0.87) were detected between diets or genetic lines for stillborn piglet percentage, average piglet birth weight, average piglet weaning weight or litter size at weaning. Results suggest young puberty sows are more likely to return to estrus under the conditions of this study.

154 A genetic marker for PRRS resistance has no adverse effect on economically important traits in pigs

Porcine Respiratory and Reproductive Syndrome (PRRS) is a very costly viral disease of pigs. A genetic marker for host response to PRRS on chromosome 4 (rs80800372, (WUR)) could be used to select for resilience to PPRS. However, before including WUR in selection, it is necessary to know effects of WUR on economically important traits without PRRS. A dataset with both genotypes and phenotypes on purebred Duroc (D), Landrace (L), Yorkshire (Y) and crossbred (LY or DLY) pigs was used. A total of 20 traits were tested. Sow reproduction and litter traits were available on > 13,000 D, L and Y and 1,549 LY sows. Growth and ultrasound traits were recorded on >35,000 D, L and Y and 2,622 DLY pigs. Daily feed intake (70-120kg) was from 4,133 Durocs. Carcass and meat quality traits were from 2,184 Durocs, 1,160 Yorkshires and 2,184 DLY pigs. All animals were genotyped using a custom SNP chip ( > 55K) including WUR. Analyses were done within each breed using an animal model. WUR was fitted as a fixed effect by classifying pigs with one or two favourable alleles (B) into one group and others into a second group. Contemporary group, parity, litter, lactation length and net fostering effects were considered depending on the traits. Relationship matrices were constructed using pedigree in purebreds and genotypes in crossbreds. WUR had no significant ( P >0.05 ) effect on any trait, except for number of pigs alive at 24hrs in Y and ultrasound loin depth in D and Y ( P< 0.05 ) but the favorable WUR allele also had favorable effects on these two traits. These results were similar to the report by Dunkelberger et al. (J. Anim. Sci. 2017, 95: 2838). In conclusion, WUR had no adverse effects on any trait and can be used to select pigs with increased resilience to PRRS.

Review: Practical Use of n-3 Fatty Acids to Improve Reproduction Parameters in the Context of Modern Sow Nutrition

The effects of long-chain polyunsaturated fatty acids (LC PUFAs) have been frequently investigated in sows because the profitability of pig production depends mainly on reproduction performance. In feeding trials, different sources and doses of n-3 PUFAs-rich feeds were used with various breeds and stages of production; however, a discrepancy in the response of n-3 PUFAs on sow reproduction has been observed. According to the results of the previous studies, n-3 fatty acids can postpone the time of parturition, decreasing the synthesis of prostaglandins, which are necessary for uterus contraction during labour. These effects could also be useful during the post-weaning period when low prostaglandin levels are indispensable for embryo survival. The n-3 fatty acids fed during the lactation period secreted in milk, may improve piglet performance. In this review, we will focus on the contradictory results of previous studies concerning practical swine nutrition. The main purpose of the review is to highlight those periods of swine breeding when the use of n-3 fatty acids may be advantageous in case of the deficiency of these essential nutrients. In finding the appropriate dose of n-3 PUFAs in terms of sow nutrition, the n-6 PUFAs levels in the given feeds must be taken into account to ensure that there are no significant reductions in the final n-6/n-3 ratio. Despite the numerous previous field trials, there are no current feeding recommendations available for PUFAs in swine nutrition. Hence, more research is required in different practical feeding situations to certify the assumptions and conclusions of this review.

Method of individual forecasting of sow reproductive performance on the basis of a non-linear canonical model of a random sequence

Improvement of sow reproductive performance is a key factor determining the efficiency of the pig production cycle and profitability of pork production. This article presents the solution of an important scientific and practical problem of individual forecasting of sow reproduction . The population used for the present study is from a pig farm managed by the Limited Liability Company (LLC) ‘Tavriys’kisvyni’ located in Skadovsky district (Kherson region, Ukraine). The experimental materials used for this study consisted of 100 inds. of productive parent sows of the Large White breed.The litter size traits – the total number of piglets born (TNB), number of piglets born alive (NBA) and number of weaned piglets (NW) – were monitored in the first eight parities over an eleven year period (2007–2017). The method of the forecasting of sow litter size is developed based on the non-linear canonical model of the random sequence of a litter size change. The proposed method allows us to take maximum account of stochastic peculiarities of sow reproductive performance and does not impose any restrictions on the random sequence of a litter size change (linearity, stationarity, Markov property, monotony, etc.). The block diagram of the algorithm presented in this work reflects the peculiarities of calculation of the parameters of a predictive model. The expression for the calculation of an extrapolation error allows us to estimate the necessary volume of a priori and a posteriori information for achieving the required quality of solving the forecasting problem. The results of the numerical experiment confirmed the high accuracy of the proposed method of forecasting of sow reproduction. The method offered by us almost doubles the accuracy of forecasting of sow litter size compared to the use of the Wiener and Kalman methods. Thus, average forecast error decreases across the range of features TNB (1.71), NBA (1.68) and NW (1.25 piglets). Apparently, this may reflect a higher level of manifestation of the genetically determined level of individual sow fertility at the moment of piglet weaning. The higher adequacy of the developed mathematical model with regard to NW can be also due to the fact that the relations between sow litter size in different farrowings primarily have a non-linear character, which is taken into maximum account in our offered model. Given non-linearity, on the other hand, turns out to be a significant factor determining a lower estimation of the repeatability value for NW compared to the estimations for TNB and NBA. The use of the developed method will help to improve the efficiency of pig farming.

181 Evaluation of feeding arginine in gestation and lactation on sow and litter performance

Two hundred sows (Camborough, PIC, Hendersonville, TN) at d 35 post-breeding were enrolled into one of four treatments to assess the required arginine level for sow reproduction. For gilts, the grams of arginine and standardized ileal digestibility (SID) per treatment consisted of: 102 g/0.69% (T1), 107 g/0.73% (T2), 112 g/0.77% (T3), and 121 g/0.83% (T4). For sows, grams of arginine and SID per treatment consisted of: 102 g/0.69% (T1), 107 g/0.73% (T2), 111 g/0.76% (T3), and 119 g/0.81% (T4). The lactation grams of arginine SID per treatment consisted of: 168 g/1.14% (T1), 176 g/1.20% (T2), 186 g/1.27% (T3), and 201 g/1.37% (T4). All diets were formulated to meet or exceed NRC. Sows were weighed farrowing and weaning weights, daily feed intake, and individual piglet and litter weights were collected. Data were analyzed as a randomized complete block design with parity as the block using the PROC MIXED procedure of SAS with the sow being the experimental unit. The feeding of different levels of SID arginine did not affect (P > 0.05) sow average daily feed intake, wean-to-estrus interval, or stillborn percent. Increasing SID arginine resulted in a linear increase (P = 0.04) in sow weaning weights (-4.41, -3.44, -4.40, and 0.61). Increasing SID arginine resulted in a tendency for a linear decrease in percent bred (100.00, 100.00, 100.00, 95.83, P = 0.06) and pre 48-hr mortality (7.58, 5.12, 4.35, 5.86, P = 0.10). Increasing levels of SID arginine resulted in no differences in piglet growth characteristics or removal or mortality percentage. Overall, the feeding of increasing levels of SID arginine resulted in improved sow weight at the time of weaning.