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Effect of pulmonary arterial pressure and annual precipitation on reproductive performance of Angus heifers in south central Wyoming

Effect of pulmonary arterial pressure and annual precipitation on reproductive performance of... Downloaded from https://academic.oup.com/tas/article/5/Supplement_S1/S175/6446440 by DeepDyve user on 07 December 2021 Effect of pulmonary arterial pressure and annual precipitation on reproductive performance of Angus heifers in south central Wyoming † ‡ †,1 †, † Kelley L. Duggan, Timothy N. Holt, Milton G. Thomas, Scott E. Speidel, and Richard M. Enns † ‡ Department of Animal Sciences, Colorado State University, Fort Collins, CO 80523-1171, USA Department of Clinical Sciences, Colorado State University, Fort Collins, CO 80523-1171, USA © The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Animal Science. This is an Open Access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com Transl. Anim. Sci. 2021.5:S175–S179 https://doi.org/10.1093/tas/txab189 environmental factors such as precipitation in- INTRODUCTION fluence reproduction of heifers at high altitude. In locations above 1,500 m, of elevation, beef Ambient temperature, humidity, radiation and producers face the challenge of pulmonary hyper- wind have an influential effect on reproductive tension, a condition that can result in high alti- efficiency (Sánchez-Castro, 2021). Because of tude disease. This hypoxic response can cause up this, it is a concern that additional stress caused to a twenty percent death loss in high altitude by differences in annual precipitation from year cattle herds (Williams et  al., 2012). Reduced at- to year would compound physiological stress in- mospheric oxygen at elevation, in combination duced by high altitude; thus, causing decreased with inefficient oxygen utilization by the bovine fertility during drought years. Therefore, the ob- cardiopulmonary system, causes alveolar-hypoxia jective of this study investigated the effect of high and pulmonary arterial vasoconstriction. With altitude on reproductive performance in Angus this vasoconstriction, significant development of heifers and how above and below annual precipi- pulmonary hypertension, right ventricular hyper- tation interact with these effects. Subsequently, trophy and progression into right ventricular dila- we hypothesized that PAP and environmental tion and failure occurs. Pulmonary arterial pressure stress, such as annual precipitation, cumulatively (PAP) testing can indicate an animal’s disposition and individually would have a negative effect on for pulmonary hypertension. According to the fertility. Beef Improvement Federation guidelines, low-risk PAP measures at 5,000 to 6,000 feet of elevation MATERIALS AND METHODS are between 34 to 39 mmHg, 40 to 45 mmHg are at moderate risk, 49 to 49  mmHg are high risk, Data were collected using protocol (#KP and scores greater than 50 mmHg are at extreme 1526)  approved by the instructional animal care risk of displaying signs of pulmonary hyperten- and use committee at Colorado State University. sion. Management decisions can be made based The Colorado State University John E.  Rouse on PAP phenotypes when managing individual Beef Improvement Center (CSU-BIC) located animals for pulmonary hypertension. northeast of Encampment, WY, at an elevation Despite the economic importance of repro- of 2,150 to 2,411 m.  The facility maintains 420 ductive performance, little is known about how head of Angus mother cows in a commercial set- ting. Heifers were artificially inseminated during 1 the third week of May at an average of 421.65 (± Corresponding author: milt.thomas@colostate.edu 20.95) days of age, following a CIDR-progesterone Received May 4, 2021. Accepted September 23, 2021. based estrus synchronization protocol. After AI S175 Downloaded from https://academic.oup.com/tas/article/5/Supplement_S1/S175/6446440 by DeepDyve user on 07 December 2021 Duggan et al. S176 services were completed, females are exposed to was observed in the year of her birth and develop- natural service bulls for 60 d. ment or the year where conception and mainten- ance of pregnancy occurred. Fertility and PAP Data Analysis Data were collected from historical records spanning the years 1993 to 2019. Data collected The relationships between PAP, fertility, and included 3,834 individual records consisting of annual precipitation were assessed using four stat- identification, sire, dam, birth year, birth weight, istical models that were implemented for both birth weaning weight, yearling weight, mating year, arti- year and breeding year in order to assess the effect ficial insemination technician (AI), AI sire, mating of precipitation on each respective biological year age, first service conception (FSC), age at first of the females. Model 1 utilized linear regression calving, PAP score, and PAP collection date. First to address PAP as a continuous variable. The re- service conception was determined through a preg- maining models, 2 to 4, executed a logistic regres- nancy evaluation using ultrasonography via rectal sion due to fertility phenotypes being a binary palpation of females at 30- and 100-d post-AI. If outcome. The model equation is presented below: a female was determined pregnant at the end of y = μ + B x + B x + e i 1 1 2 2 i the breeding season through a pregnancy evalu- Where y was the vector of observed pheno- ation using ultrasonography via rectal palpation, i types for the trait of interest, which included PAP, overall heifer pregnancy (HPG) was assigned. If FSC, and HPG, µ was the overall mean of the ob- a female was found to be not pregnant, then she servations, B was the slope of the regression line was culled. The PAP measures were collected when 1 of the continuous covariable, x was the vector of heifers were approximately 12 mo of age. The PAP 1 predictor variables for the fixed effect of the con- collection was performed by the same Colorado/ tinuous variable precipitation, B was the parameter Wyoming licensed veterinarian every year using 2 of the population regression line of the continuous procedures described by Holt and Callan (2007). fixed effect of age, x was the vector of predictor Briefly, a polyethylene catheter is inserted into the 2 variables for the continuous fixed effect of age, and pulmonary pulmonary artery. The mean logarithm e was the vector of random residuals. The pheno- of systolic and diastolic pulmonary artery pressure i type and climate variables used in each model fol- was collected via a pressure transducer connected lows Table 1. to the catheter. Basing knowledge off risk factors Type III sums of squares were calculated for each associated with PAP, a PAP score of 41 and below model to determine important (P < 0.05) sources of was considered the cut off for females to a good variation. It should be noted that Model 3 was only candidate to be replacement females in the CSU- executed once due to the variables being assessed BIC herd. included PAP and AI age, with fertility being the Annual Precipitation Table 1.  Phenotypic and climate traits evaluated in each regression model assessing relationship be- Precipitation data were collected from the tween PAP, fertility traits, and annual precipitation National Oceanic and Atmospheric Administration for data from yearling Angus heifers (n  =  3,834) (https://www.ncdc.noaa.gov/cag/). Data for Carbon raised at altitude (2,150–2,411 m) County, Wyoming, were sourced for the years that fertility and PAP data were sourced (1993 to 2019), Traits along with the historical average. Using this annual AI Yearling Model Trait PAP A/B Age PAP*A/B Year precipitation data, each calendar year was assigned 1 PAP x x X a precipitation classification, “1” for above (A) 2 FSC/ x x X average precipitation, or “0” for below (B) average HPG precipitation. Using this knowledge, two response 3 FSC/ x x X variables were created based on the precipitation HPG classification (A/B variable). A birth year precipita- 4 FSC/ x x X HPG tion classification was created and a breeding year classification was created. This was done to assess A/B, above or below precipitation; AI Age, age at artificial insem- the effect of precipitation on heifer fertility per- ination; PAP*A/B, interaction between pulmonary arterial pressure formance if above or below average precipitation (mmHg) and precipitation (above or below). Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article/5/Supplement_S1/S175/6446440 by DeepDyve user on 07 December 2021 Effect of pulmonary arterial pressure and annual precipitation S177 response. Biological year was not included; hence it shown to have negative relationships according to did not need to be run for both breeding and birth their slope coefficients (−0.0015 to −0.278) while year. All data were analyzed using the R statistical there were positive relationships between precipi- software package (R Core Team, 2020). tation and the fertility traits (0.1376 to 0.5268) (Tables 3 and 4). Two exceptions were observed in RESULTS these relationships, Model 2 for FSC and breeding year (−0.0688) and Model 4 HPG with birth year Results for annual precipitation and fertility (−0.7687) had a negative relationship between pre- are shown in Figure 1. Summary statistics for heifer cipitation and fertility traits. fertility traits, age, and PAP are presented in Table 2. In regards to the breeding year models (Table DISCUSSION 3), for model 1, age and precipitation were signifi- cant predictors of PAP (P < 0.05). In model 2, age In this study, using these data, we observed accounted for variability in both HPG and FSC, that PAP influenced HPG but not FSC. Ultimately, while precipitation was only a significant predictor it is the hypoxic environment that leads to right of HPG. Pulmonary arterial pressure was shown to side heart failure due to pulmonary hypertension. be a significant predictor of HPG in model 3, while During a state of hypoxia, tissue becomes necrotic age again accounted for variation in both HPG and (Holt and Callan, 2007). This could be an issue if FSC. For model 4, age was a predictor of FSC. Age the uterine environment is negatively affected due also predicted HPG; however, a tendency was ob- to the lack of oxygen. The fetus is highly sensitive served for the interaction of age and rainfall as pre- to changes in the uterine environment, which can cipitation was an important source of variation in lead to embryonic loss if a shift in oxygen supply the analysis of HPG (P = 0.09). As for birth year models (Table 4), precipitation Table 2.  Summary statistics for phenotypic obser- and age were again significant predictors of PAP. vations of yearling Angus heifers (n = 3,834) raised However, in model 2, age was related to both FSC at altitude (2,150–2,411 m) and HPG, while precipitation was an indicator for FSC. In the final model, age predicted both FSC Phenotype Mean SD Minimum Maximum AI Age, days 421.65 20.95 347 476 and HPG, while PAP and its interaction with pre- PAP, mmHg 41.09 7.52 21 129 cipitation was an indicator for HPG. Overall, in FSC, % 47% 10% 27% 68% both breeding and birth models, the amount of HPG, % 85% 8% 64% 96% variation accounted by the models was limited (R < 0.014). Finally, PAP and fertility traits were AI Age, age at artificial insemination. Figure 1. Annual precipitation amount in centimeters per year in Carbon County, WY, first service conception rates (FSC) and overall preg- nancy rates (HPG) for yearling Angus heifers (n = 3,834) raised at altitude (2,150–2,411 m). Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article/5/Supplement_S1/S175/6446440 by DeepDyve user on 07 December 2021 Duggan et al. S178 Table 3. Results of models with explanatory variables and coefficient of determination values for breeding year models assessing relationship of PAP, precipitation (A/B), and age (AI Age) for data from yearling Angus heifers (n = 3,834) raised at altitude (2,150–2,411 m) Breeding year Effect (P-value) Slope coefficients Model Response PAP A/B AI Age PAP*A/B PAP A/B R a a Model 1 PAP <0.0001 <0.0001 1.2020 0.0111 Model 2 FSC 0.2945 0.0060 −0.0688 0.0028 a a HPG 0.0237 <0.0001 0.2114 0.0087 Model 3 FSC 0.0778 0.0030 −0.0077 0.0033 a a HPG 0.0015 <0.0001 −0.0177 0.0099 Model 4 FSC 0.7970 0.2220 0.0041 0.1597 −0.0015 0.4527 0.0040 a a HPG 0.2002 0.0311 <0.0001 0.0924 −0.0101 0.9924 0.0131 A/B, above or below precipitation; AI Age, age at artificial insemination; R , coefficient of determination; PAP*A/B, interaction between pul- monary arterial pressure (mmHg) and precipitation (above or below). Within each column, superscripts indicate significance (P < 0.05). Table 4. Results of models with explanatory variables and coefficient of determination value for birth year models assessing relationship of PAP, precipitation (A/B), and age (AI Age) for data from yearling Angus heifers (n = 3,834) raised at altitude (2,150–2,411 m) Birth year Effect (P-value) Slope coefficients Model Response PAP A/B AI Age PAP*A/B PAP A/B R a a Model 1 PAP 0.0342 <0.0001 0.5268 0.0060 a a Model 2 FSC 0.0055 0.0062 0.1851 0.0044 HPG 0.1476 <0.0001 0.1376 0.0077 Model 4 FSC 0.2326 0.5125 0.0041 0.8868 −0.0015 0.4527 0.0053 a a HPG 0.0002 0.1021 <0.0001 0.0458 −0.0278 −0.7687 0.0123 A/B, above or below precipitation; AI Age, age at artificial insemination; R , coefficient of determination; PAP*A/B, interaction between pul- monary arterial pressure (mmHg) and precipitation (above or below). Within each column, superscripts indicate significance (P < 0.05). occurs. The placenta facilitates the exchange of precipitation and HPG in breeding years. However, gases and liquids from dam to fetus. If the dam is it has been shown that heifers must reach 66% of hypoxic, it is plausible that the fetus is not receiving their mature body weight to reach sexual maturity. enough oxygen, even in the low oxygen environ- If drought occurred during an animal’s birth year ment of the uterus (Jauniaux et al., 2005). A dam and subsequent growth through about 9 mo of age, that has a high PAP score may have reduced oxygen nutrients would be reduced, negatively affecting the levels in comparison to low PAP individuals; there- growth and sexual development of the heifer. This fore, these types of physiological phenomena may could potentially affect her ability to be developed explain pregnancy rate differences between high and sexually mature to conceive at first service by and low PAP females. 421 d of age. Precipitation influenced both PAP and fertility The relationship between PAP and fertility traits rates in this study. Specifically, results were that pre- appears to be negative, which is expected. As PAP in- cipitation in the breeding year affected HPG and creases, fertility decreases. As for the relationship be- precipitation in birth years influenced FSC. These tween precipitation and fertility, for the majority of results could be attributed to how forage nutri- the models, the relationship was positive. This is as tion is influenced by precipitation. It is known that one would expect, with more precipitation, fertility in- drought and low precipitation will negatively affect creases. However, for FSC, precipitation in the breeding the nutrient levels of forage (Scasta et al., 2015). If year indicated a negative relationship. This could be the forage is negatively affected during a breeding explained from the aspect that precipitation received year, overall maintenance of pregnancy could in Encampment, Wyoming in high precipitation years be affected, explaining the relationship between occurs as snow. This would mean that females would Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article/5/Supplement_S1/S175/6446440 by DeepDyve user on 07 December 2021 Effect of pulmonary arterial pressure and annual precipitation S179 Angus cattle at high altitude. J. Anim. Sci. 94:4483–4490. experience a harsh winter and cold stress immediately doi:10.2527/jas.2016-0703 prior to breeding, potentially affecting their ability Holt, T. N., and R. J. Callan. 2007. Pulmonary arterial pressure to conceive at first service (Sánchez-Castro, 2021). testing for high mountain disease in cattle. Vet. Clin. North Investigating how defining precipitation ranking based Am. Food Anim. Pract. 23:575–96, vii. doi:10.1016/j. on a biological year versus a calendar year could pro- cvfa.2007.08.001 Jauniaux,  E., J.  Hempstock, C.  Teng, F.  C.  Battaglia, and vide further insight into the relationship. Further re- G.  J.  Burton. 2005. Polyol concentrations in the fluid search could also explore how multiple above or below compartments of the human conceptus during the first average precipitation years in a row affect fertility and trimester of pregnancy: maintenance of redox potential PAP. In conclusion, with low coefficients of determin- in a low oxygen environment. J. Clin. Endocrinol. Metab. ation, it was found that environmental factors such as 90(2):1171–1175. doi:10.1210/jc.2004-1513 altitude and precipitation were associated with fertility Pauling, R. C., S. E. Speidel, M. G. Thomas, T. N. Holt, and R.  M.  Enns. 2018. Evaluation of moderate to high ele- traits in yearling Angus heifers. vation effects on pulmonary arterial pressure measures in Angus cattle1. J. Anim. Sci. 96:3599–3605. doi:10.1093/ ACKNOWLEDGMENTS jas/sky262 R Core Team. 2020. R: a language and environment for stat- The authors would like to acknowledge the istical computing. Vienna (Austria): R Foundation for University of Wyoming Extension Service, specif- Statistical Computing. https://www.R-project.org/ ically Regional Extension Program Coordinator, Sánchez-Castro, M. A. 2021. Random regression models and USDA NPCH, Windy Kelley and Carbon County their impact in the genetic evaluation of binary fertility traits in beef cattle. PhD Diss. Colorado State University, Rangeland Extension Educator, Abby Perry for Fort Collins. their assistance locating precipitation data. This Scasta,  J.D., J.  L.  Windh, T.  Smith, and B.  Baumgartner. work is supported by USDA National Institute of 2015. Drought consequences for cow- calf production Food and Agriculture Hatch project COLO0607A, in Wyoming: 2011-2014. Rangelands. 37(5):71–177. accession number 1006304 and COLO0681A, ac- doi:10.1016/j.rala.2015.07.001 cession number 1010007. Speidel,  S.  E., M.  G.  Thomas, T.  N.  Holt, and R.  M.  Enns. 2020. Evaluation of the sensitivity of pulmonary ar- Conflict of interest statement. The authors de- terial pressure to elevation using a reaction norm model clare that they have no conflict of interest. in Angus Cattle. J. Anim. Sci. 98(5):1–9. doi:10.1093/jas/ skaa129 LITERATURE CITED Williams, J. L., J. K. Bertrand, I. Misztal, and M. Łukaszewicz. 2012. Genotype by environment interaction for growth Crawford, N. F., M. G. Thomas, T. N. Holt, S. E. Speidel, and due to altitude in United States Angus cattle. J. Anim. Sci. R. M. Enns. 2016. Heritabilities and genetic correlations 90:2152–2158. doi:10.2527/jas.2011-4365 of pulmonary arterial pressure and performance traits in Translate basic science to industry innovation http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Translational Animal Science Oxford University Press

Effect of pulmonary arterial pressure and annual precipitation on reproductive performance of Angus heifers in south central Wyoming

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Downloaded from https://academic.oup.com/tas/article/5/Supplement_S1/S175/6446440 by DeepDyve user on 07 December 2021 Effect of pulmonary arterial pressure and annual precipitation on reproductive performance of Angus heifers in south central Wyoming † ‡ †,1 †, † Kelley L. Duggan, Timothy N. Holt, Milton G. Thomas, Scott E. Speidel, and Richard M. Enns † ‡ Department of Animal Sciences, Colorado State University, Fort Collins, CO 80523-1171, USA Department of Clinical Sciences, Colorado State University, Fort Collins, CO 80523-1171, USA © The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Animal Science. This is an Open Access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com Transl. Anim. Sci. 2021.5:S175–S179 https://doi.org/10.1093/tas/txab189 environmental factors such as precipitation in- INTRODUCTION fluence reproduction of heifers at high altitude. In locations above 1,500 m, of elevation, beef Ambient temperature, humidity, radiation and producers face the challenge of pulmonary hyper- wind have an influential effect on reproductive tension, a condition that can result in high alti- efficiency (Sánchez-Castro, 2021). Because of tude disease. This hypoxic response can cause up this, it is a concern that additional stress caused to a twenty percent death loss in high altitude by differences in annual precipitation from year cattle herds (Williams et  al., 2012). Reduced at- to year would compound physiological stress in- mospheric oxygen at elevation, in combination duced by high altitude; thus, causing decreased with inefficient oxygen utilization by the bovine fertility during drought years. Therefore, the ob- cardiopulmonary system, causes alveolar-hypoxia jective of this study investigated the effect of high and pulmonary arterial vasoconstriction. With altitude on reproductive performance in Angus this vasoconstriction, significant development of heifers and how above and below annual precipi- pulmonary hypertension, right ventricular hyper- tation interact with these effects. Subsequently, trophy and progression into right ventricular dila- we hypothesized that PAP and environmental tion and failure occurs. Pulmonary arterial pressure stress, such as annual precipitation, cumulatively (PAP) testing can indicate an animal’s disposition and individually would have a negative effect on for pulmonary hypertension. According to the fertility. Beef Improvement Federation guidelines, low-risk PAP measures at 5,000 to 6,000 feet of elevation MATERIALS AND METHODS are between 34 to 39 mmHg, 40 to 45 mmHg are at moderate risk, 49 to 49  mmHg are high risk, Data were collected using protocol (#KP and scores greater than 50 mmHg are at extreme 1526)  approved by the instructional animal care risk of displaying signs of pulmonary hyperten- and use committee at Colorado State University. sion. Management decisions can be made based The Colorado State University John E.  Rouse on PAP phenotypes when managing individual Beef Improvement Center (CSU-BIC) located animals for pulmonary hypertension. northeast of Encampment, WY, at an elevation Despite the economic importance of repro- of 2,150 to 2,411 m.  The facility maintains 420 ductive performance, little is known about how head of Angus mother cows in a commercial set- ting. Heifers were artificially inseminated during 1 the third week of May at an average of 421.65 (± Corresponding author: milt.thomas@colostate.edu 20.95) days of age, following a CIDR-progesterone Received May 4, 2021. Accepted September 23, 2021. based estrus synchronization protocol. After AI S175 Downloaded from https://academic.oup.com/tas/article/5/Supplement_S1/S175/6446440 by DeepDyve user on 07 December 2021 Duggan et al. S176 services were completed, females are exposed to was observed in the year of her birth and develop- natural service bulls for 60 d. ment or the year where conception and mainten- ance of pregnancy occurred. Fertility and PAP Data Analysis Data were collected from historical records spanning the years 1993 to 2019. Data collected The relationships between PAP, fertility, and included 3,834 individual records consisting of annual precipitation were assessed using four stat- identification, sire, dam, birth year, birth weight, istical models that were implemented for both birth weaning weight, yearling weight, mating year, arti- year and breeding year in order to assess the effect ficial insemination technician (AI), AI sire, mating of precipitation on each respective biological year age, first service conception (FSC), age at first of the females. Model 1 utilized linear regression calving, PAP score, and PAP collection date. First to address PAP as a continuous variable. The re- service conception was determined through a preg- maining models, 2 to 4, executed a logistic regres- nancy evaluation using ultrasonography via rectal sion due to fertility phenotypes being a binary palpation of females at 30- and 100-d post-AI. If outcome. The model equation is presented below: a female was determined pregnant at the end of y = μ + B x + B x + e i 1 1 2 2 i the breeding season through a pregnancy evalu- Where y was the vector of observed pheno- ation using ultrasonography via rectal palpation, i types for the trait of interest, which included PAP, overall heifer pregnancy (HPG) was assigned. If FSC, and HPG, µ was the overall mean of the ob- a female was found to be not pregnant, then she servations, B was the slope of the regression line was culled. The PAP measures were collected when 1 of the continuous covariable, x was the vector of heifers were approximately 12 mo of age. The PAP 1 predictor variables for the fixed effect of the con- collection was performed by the same Colorado/ tinuous variable precipitation, B was the parameter Wyoming licensed veterinarian every year using 2 of the population regression line of the continuous procedures described by Holt and Callan (2007). fixed effect of age, x was the vector of predictor Briefly, a polyethylene catheter is inserted into the 2 variables for the continuous fixed effect of age, and pulmonary pulmonary artery. The mean logarithm e was the vector of random residuals. The pheno- of systolic and diastolic pulmonary artery pressure i type and climate variables used in each model fol- was collected via a pressure transducer connected lows Table 1. to the catheter. Basing knowledge off risk factors Type III sums of squares were calculated for each associated with PAP, a PAP score of 41 and below model to determine important (P < 0.05) sources of was considered the cut off for females to a good variation. It should be noted that Model 3 was only candidate to be replacement females in the CSU- executed once due to the variables being assessed BIC herd. included PAP and AI age, with fertility being the Annual Precipitation Table 1.  Phenotypic and climate traits evaluated in each regression model assessing relationship be- Precipitation data were collected from the tween PAP, fertility traits, and annual precipitation National Oceanic and Atmospheric Administration for data from yearling Angus heifers (n  =  3,834) (https://www.ncdc.noaa.gov/cag/). Data for Carbon raised at altitude (2,150–2,411 m) County, Wyoming, were sourced for the years that fertility and PAP data were sourced (1993 to 2019), Traits along with the historical average. Using this annual AI Yearling Model Trait PAP A/B Age PAP*A/B Year precipitation data, each calendar year was assigned 1 PAP x x X a precipitation classification, “1” for above (A) 2 FSC/ x x X average precipitation, or “0” for below (B) average HPG precipitation. Using this knowledge, two response 3 FSC/ x x X variables were created based on the precipitation HPG classification (A/B variable). A birth year precipita- 4 FSC/ x x X HPG tion classification was created and a breeding year classification was created. This was done to assess A/B, above or below precipitation; AI Age, age at artificial insem- the effect of precipitation on heifer fertility per- ination; PAP*A/B, interaction between pulmonary arterial pressure formance if above or below average precipitation (mmHg) and precipitation (above or below). Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article/5/Supplement_S1/S175/6446440 by DeepDyve user on 07 December 2021 Effect of pulmonary arterial pressure and annual precipitation S177 response. Biological year was not included; hence it shown to have negative relationships according to did not need to be run for both breeding and birth their slope coefficients (−0.0015 to −0.278) while year. All data were analyzed using the R statistical there were positive relationships between precipi- software package (R Core Team, 2020). tation and the fertility traits (0.1376 to 0.5268) (Tables 3 and 4). Two exceptions were observed in RESULTS these relationships, Model 2 for FSC and breeding year (−0.0688) and Model 4 HPG with birth year Results for annual precipitation and fertility (−0.7687) had a negative relationship between pre- are shown in Figure 1. Summary statistics for heifer cipitation and fertility traits. fertility traits, age, and PAP are presented in Table 2. In regards to the breeding year models (Table DISCUSSION 3), for model 1, age and precipitation were signifi- cant predictors of PAP (P < 0.05). In model 2, age In this study, using these data, we observed accounted for variability in both HPG and FSC, that PAP influenced HPG but not FSC. Ultimately, while precipitation was only a significant predictor it is the hypoxic environment that leads to right of HPG. Pulmonary arterial pressure was shown to side heart failure due to pulmonary hypertension. be a significant predictor of HPG in model 3, while During a state of hypoxia, tissue becomes necrotic age again accounted for variation in both HPG and (Holt and Callan, 2007). This could be an issue if FSC. For model 4, age was a predictor of FSC. Age the uterine environment is negatively affected due also predicted HPG; however, a tendency was ob- to the lack of oxygen. The fetus is highly sensitive served for the interaction of age and rainfall as pre- to changes in the uterine environment, which can cipitation was an important source of variation in lead to embryonic loss if a shift in oxygen supply the analysis of HPG (P = 0.09). As for birth year models (Table 4), precipitation Table 2.  Summary statistics for phenotypic obser- and age were again significant predictors of PAP. vations of yearling Angus heifers (n = 3,834) raised However, in model 2, age was related to both FSC at altitude (2,150–2,411 m) and HPG, while precipitation was an indicator for FSC. In the final model, age predicted both FSC Phenotype Mean SD Minimum Maximum AI Age, days 421.65 20.95 347 476 and HPG, while PAP and its interaction with pre- PAP, mmHg 41.09 7.52 21 129 cipitation was an indicator for HPG. Overall, in FSC, % 47% 10% 27% 68% both breeding and birth models, the amount of HPG, % 85% 8% 64% 96% variation accounted by the models was limited (R < 0.014). Finally, PAP and fertility traits were AI Age, age at artificial insemination. Figure 1. Annual precipitation amount in centimeters per year in Carbon County, WY, first service conception rates (FSC) and overall preg- nancy rates (HPG) for yearling Angus heifers (n = 3,834) raised at altitude (2,150–2,411 m). Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article/5/Supplement_S1/S175/6446440 by DeepDyve user on 07 December 2021 Duggan et al. S178 Table 3. Results of models with explanatory variables and coefficient of determination values for breeding year models assessing relationship of PAP, precipitation (A/B), and age (AI Age) for data from yearling Angus heifers (n = 3,834) raised at altitude (2,150–2,411 m) Breeding year Effect (P-value) Slope coefficients Model Response PAP A/B AI Age PAP*A/B PAP A/B R a a Model 1 PAP <0.0001 <0.0001 1.2020 0.0111 Model 2 FSC 0.2945 0.0060 −0.0688 0.0028 a a HPG 0.0237 <0.0001 0.2114 0.0087 Model 3 FSC 0.0778 0.0030 −0.0077 0.0033 a a HPG 0.0015 <0.0001 −0.0177 0.0099 Model 4 FSC 0.7970 0.2220 0.0041 0.1597 −0.0015 0.4527 0.0040 a a HPG 0.2002 0.0311 <0.0001 0.0924 −0.0101 0.9924 0.0131 A/B, above or below precipitation; AI Age, age at artificial insemination; R , coefficient of determination; PAP*A/B, interaction between pul- monary arterial pressure (mmHg) and precipitation (above or below). Within each column, superscripts indicate significance (P < 0.05). Table 4. Results of models with explanatory variables and coefficient of determination value for birth year models assessing relationship of PAP, precipitation (A/B), and age (AI Age) for data from yearling Angus heifers (n = 3,834) raised at altitude (2,150–2,411 m) Birth year Effect (P-value) Slope coefficients Model Response PAP A/B AI Age PAP*A/B PAP A/B R a a Model 1 PAP 0.0342 <0.0001 0.5268 0.0060 a a Model 2 FSC 0.0055 0.0062 0.1851 0.0044 HPG 0.1476 <0.0001 0.1376 0.0077 Model 4 FSC 0.2326 0.5125 0.0041 0.8868 −0.0015 0.4527 0.0053 a a HPG 0.0002 0.1021 <0.0001 0.0458 −0.0278 −0.7687 0.0123 A/B, above or below precipitation; AI Age, age at artificial insemination; R , coefficient of determination; PAP*A/B, interaction between pul- monary arterial pressure (mmHg) and precipitation (above or below). Within each column, superscripts indicate significance (P < 0.05). occurs. The placenta facilitates the exchange of precipitation and HPG in breeding years. However, gases and liquids from dam to fetus. If the dam is it has been shown that heifers must reach 66% of hypoxic, it is plausible that the fetus is not receiving their mature body weight to reach sexual maturity. enough oxygen, even in the low oxygen environ- If drought occurred during an animal’s birth year ment of the uterus (Jauniaux et al., 2005). A dam and subsequent growth through about 9 mo of age, that has a high PAP score may have reduced oxygen nutrients would be reduced, negatively affecting the levels in comparison to low PAP individuals; there- growth and sexual development of the heifer. This fore, these types of physiological phenomena may could potentially affect her ability to be developed explain pregnancy rate differences between high and sexually mature to conceive at first service by and low PAP females. 421 d of age. Precipitation influenced both PAP and fertility The relationship between PAP and fertility traits rates in this study. Specifically, results were that pre- appears to be negative, which is expected. As PAP in- cipitation in the breeding year affected HPG and creases, fertility decreases. As for the relationship be- precipitation in birth years influenced FSC. These tween precipitation and fertility, for the majority of results could be attributed to how forage nutri- the models, the relationship was positive. This is as tion is influenced by precipitation. It is known that one would expect, with more precipitation, fertility in- drought and low precipitation will negatively affect creases. However, for FSC, precipitation in the breeding the nutrient levels of forage (Scasta et al., 2015). If year indicated a negative relationship. This could be the forage is negatively affected during a breeding explained from the aspect that precipitation received year, overall maintenance of pregnancy could in Encampment, Wyoming in high precipitation years be affected, explaining the relationship between occurs as snow. This would mean that females would Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article/5/Supplement_S1/S175/6446440 by DeepDyve user on 07 December 2021 Effect of pulmonary arterial pressure and annual precipitation S179 Angus cattle at high altitude. J. Anim. Sci. 94:4483–4490. experience a harsh winter and cold stress immediately doi:10.2527/jas.2016-0703 prior to breeding, potentially affecting their ability Holt, T. N., and R. J. Callan. 2007. Pulmonary arterial pressure to conceive at first service (Sánchez-Castro, 2021). testing for high mountain disease in cattle. Vet. Clin. North Investigating how defining precipitation ranking based Am. Food Anim. Pract. 23:575–96, vii. doi:10.1016/j. on a biological year versus a calendar year could pro- cvfa.2007.08.001 Jauniaux,  E., J.  Hempstock, C.  Teng, F.  C.  Battaglia, and vide further insight into the relationship. Further re- G.  J.  Burton. 2005. Polyol concentrations in the fluid search could also explore how multiple above or below compartments of the human conceptus during the first average precipitation years in a row affect fertility and trimester of pregnancy: maintenance of redox potential PAP. In conclusion, with low coefficients of determin- in a low oxygen environment. J. Clin. Endocrinol. Metab. ation, it was found that environmental factors such as 90(2):1171–1175. doi:10.1210/jc.2004-1513 altitude and precipitation were associated with fertility Pauling, R. C., S. E. Speidel, M. G. Thomas, T. N. Holt, and R.  M.  Enns. 2018. Evaluation of moderate to high ele- traits in yearling Angus heifers. vation effects on pulmonary arterial pressure measures in Angus cattle1. J. Anim. Sci. 96:3599–3605. doi:10.1093/ ACKNOWLEDGMENTS jas/sky262 R Core Team. 2020. R: a language and environment for stat- The authors would like to acknowledge the istical computing. Vienna (Austria): R Foundation for University of Wyoming Extension Service, specif- Statistical Computing. https://www.R-project.org/ ically Regional Extension Program Coordinator, Sánchez-Castro, M. A. 2021. Random regression models and USDA NPCH, Windy Kelley and Carbon County their impact in the genetic evaluation of binary fertility traits in beef cattle. PhD Diss. Colorado State University, Rangeland Extension Educator, Abby Perry for Fort Collins. their assistance locating precipitation data. This Scasta,  J.D., J.  L.  Windh, T.  Smith, and B.  Baumgartner. work is supported by USDA National Institute of 2015. Drought consequences for cow- calf production Food and Agriculture Hatch project COLO0607A, in Wyoming: 2011-2014. Rangelands. 37(5):71–177. accession number 1006304 and COLO0681A, ac- doi:10.1016/j.rala.2015.07.001 cession number 1010007. Speidel,  S.  E., M.  G.  Thomas, T.  N.  Holt, and R.  M.  Enns. 2020. Evaluation of the sensitivity of pulmonary ar- Conflict of interest statement. The authors de- terial pressure to elevation using a reaction norm model clare that they have no conflict of interest. in Angus Cattle. J. Anim. Sci. 98(5):1–9. doi:10.1093/jas/ skaa129 LITERATURE CITED Williams, J. L., J. K. Bertrand, I. Misztal, and M. Łukaszewicz. 2012. Genotype by environment interaction for growth Crawford, N. F., M. G. Thomas, T. N. Holt, S. E. Speidel, and due to altitude in United States Angus cattle. J. Anim. Sci. R. M. Enns. 2016. Heritabilities and genetic correlations 90:2152–2158. doi:10.2527/jas.2011-4365 of pulmonary arterial pressure and performance traits in Translate basic science to industry innovation

Journal

Translational Animal Science – Oxford University Press

Published: Nov 30, 2021

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