Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Jul 24;14(15):2150.
doi: 10.3390/ani14152150.

Reproductive Capabilities of Female Nilgai (Boselaphus tragocamelus) in Southern Texas

Megan M Granger  1 , Clayton D Hilton  2 , Scott E Henke  2 , Humberto L Perotto-Baldivieso  3 , Landon R Schofield  4 , Tyler A Campbell  4
Affiliations

Reproductive Capabilities of Female Nilgai (Boselaphus tragocamelus) in Southern Texas

Megan M Granger et al. Animals (Basel). .

Abstract

Free-ranging nilgai antelope (Boselaphus tragocamelus) are an understudied species, both on their native ranges of India, Pakistan, and Nepal and on their introduced ranges in southern Texas. Basic data related to population sizes, survival, reproduction, and recruitment are needed throughout their range to inform management and conservation decisions. We collected nilgai fetuses from 3 ranches in southern Texas, including East Foundation's El Sauz and Santa Rosa ranches, and the Norias Division of the King Ranch® from 2018-2021. We calculated the percentage of individuals that were pregnant in each of the sample years and overall. We determined monthly average, maximum, and minimum fetus length. Of 488 nilgai cows, we found 386 to be pregnant (79%) and 214 to be pregnant with twins (56%). We found nilgai cows as young as 1-year old to have fetuses and therefore to have reached sexual maturity. Sex ratios of fetuses during any sampling year did not differ. We found ample evidence supporting our hypothesis that nilgai are fecund on their introduced range of southern Texas. To prevent nilgai overpopulation and associated problems, harvest management strategies should be implemented, specifically on nilgai cows.

Keywords: nilgai; pregnancy rates; reproduction; twinning.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Red star is location of East Foundation’s Santa Rosa and El Sauz ranches and King Ranch® Norias Division, where we collected fetuses from pregnant nilgai (Boselaphus tragocamelus) cows from 2018 to 2021.
Figure 2
Figure 2
(a) Percentages of pregnant nilgai (Boselaphus tragocamelus) cows that were sampled on 3 Southern Texas ranches from 2018 to 2021 by age class (class 2 = 1 year old, class 3 = 2–4 years old, class 4 = 5–7 years old, class 5 = 8–11 years old, and class 6 = ≥12 years old [8]). (b) Percentages of nilgai pregnancies that were twins by age class (see above) on 3 Southern Texas ranches from 2018 to 2021. We considered statistical significance at p < 0.05.
Figure 3
Figure 3
Average, maximum, and minimum fetus crown rump lengths of fetuses collected from pregnant nilgai (Boselaphus tragocamelus) cows (≥1 year old) by month, which were sampled on 3 Southern Texas ranches from 2018 to 2021. The solid line is the average length, the dotted line is the minimum length, and the dashed line is the maximum length.
See this image and copyright information in PMC

References

    1. Khanal S., Aryal A., Morley C.G., Wright W., Singh N.B. Challenges of conserving blue bull (Boselaphus tragocamelus) outside the protected areas of Nepal. Proc. Zool. Soc. 2017;71:352–362. doi: 10.1007/s12595-017-0218-y. - DOI
    1. Basak K., Mandal D., Babu S., Kaul R., Ashraf N.V.K., Singh A., Mondal K. Prey animals of tiger (Panthera tigris tigris) in Dudhwa landscape, Terai region, north India. Proc. Zool. Soc. 2018;71:92–98. doi: 10.1007/s12595-016-0196-5. - DOI
    1. Goolsby J.A., Saelao P., May M., Goldsmith B. Nilgai (Boselaphus tragocamelus) mortality levels in South Texas after historic freeze event. Subtrop. Agric. Environ. 2021;72:7–11.
    1. Mungall E.C., Sheffield W.J. Exotics on the Range: The Texas Example. Texas A&M University Press; College Station, TX, USA: 1994. pp. 58–62.
    1. Sheffield W.J. Food habits of nilgai antelope in Texas. J. Range Manag. 1983;36:316–322. doi: 10.2307/3898478. - DOI

LinkOut - more resources