The objective of the present study was to evaluate the influence of growth rate from 3 to 12 months of age on the onset of puberty, libido and fertility of boars

Reed, J. D.

Rich, T. D.

English

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South Dakota State UniversityOpen PRAIRIE: Open Public Research Access InstitutionalRepository and Information ExchangeSouth Dakota Swine Field Day Proceedings andResearch Reports, 1971 Animal Science Reports1971Influence of Growth Rate from Three to TwelveMonths of Age on Reproductive Characteristics ofBoarsJ. D. ReedSouth Dakota State UniversityT. D. RichFollow this and additional works at: http://openprairie.sdstate.edu/sd_swine_1971This Report is brought to you for free and open access by the Animal Science Reports at Open PRAIRIE: Open Public Research Access InstitutionalRepository and Information Exchange. It has been accepted for inclusion in South Dakota Swine Field Day Proceedings and Research Reports, 1971 byan authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For moreinformation, please contact michael.biondo@sdstate.edu.Recommended CitationReed, J. D. and Rich, T. D., "Influence of Growth Rate from Three to Twelve Months of Age on Reproductive Characteristics of Boars"(1971). South Dakota Swine Field Day Proceedings and Research Reports, 1971. Paper 2.http://openprairie.sdstate.edu/sd_swine_1971/2S outh Dakota S tate University Brookings , South Dakota Department of Animal Science Agricultural Experiment S tation A . S .  Series 71-30 Influence of Growth Rate from Three to Twelve Months o f  Age on Reproductive Characteris tics of Boars J .  D. Reed and T .  D .  Rich Little definitive information is known concerning the influence o f  nutrition on boar development and subsequent fertility . In s ingle s tudies conducted at the University of Kentucky on b oars less than one year of age and at the University of Wisconsin on mature boars, it was concluded that development and functional capacity of the boar reproductive sys tem is relatively resis tant to the effects of under- and over-feeding . The obj ective of the present s tudy was to evaluate the influence o f  growth rate from 3 to 12 months o f  age on the onset  o f  puberty, lib ido and fertility o f  b oars . Experimental Procedure Six related crossbred b oars (predominantly Yorkshire) were allotted to three treatment groups when they were 90 days of age and remained on thes e planned growth rates lllltil one year o f  age . The three treatments consis ted of adj usting the feed level to control rate of gain at approximately 0.75 lb . per day (Group I) , 1.25 lb . p er day ( Group II)  and 1.75 lb . per day (Group III) . The boars were fed a 14% corn-soy diet once daily in individual crates , provided water ad libitum and housed in adj acent pens . Feed levels were adj us ted bimonthly depending upon weight gains . B oars were teased with es trus females twice weekly beginning at 5 months o f  age . A boar was classified to have reached puberty when an ejaculate containing motile sperm cells could be ob tained by the gloved hand collection technique . At one year o f  age, libido and fertility were es timated by breeding each b oar to 6 or 7 gilts . Libido was es timated by determining the time it required for the boar to detect a gilt in es trus and to complete copulation . Fertility was es timated by determining the embryo survival of 30 to 35 day pregnant gilts . Results The actual growth rates ob tained are shown in figure 1. During the experi­mental period o f  Sep tember through March, the average daily gains were 1.0 , 1 .3 and 1.5 lb . per day for Groups I ,  II and III, respectively . Age at puberty of boars in Groups II  and II I, along with one boar in Group I ,  ranged from 167 to 1 85 days ( table 1) . Boar 73-8 in Group I did not reach puberty until 262 days of age . Differences in libido of thes e boars are shown in table 2. Boars grown at the s lower rate (Group I) tended to take longer to detect gilts in es trus and s lightly longer to gain intromission than boars in Groups II  and III. There were 5 no differences in lib ido between Groups II and III .  This is a crude es timate of libido but indicates that a slight depression might occur subsequent to under nutrition . Similar results have b een reported in bulls . Subsequent to the different nutritional regimes, there was no indication of an alteration in fertility ( table 3) . There were no significant differences in pregnancy rate or embryo survival among any o f  the treatment groups . Swnmary Preliminary results gathered from six related crossbred boars suggest that growing boars at or near 1 lb . per day may increase age at puberty and depress libido but does not appear to alter subsequent fertility . Table 1 .  Influence of Growth Rate on Age of Puberty in Boars Age at Treatment puberty group Boar ( days) I 73-8 262  7 7-7 185 II 73-10 183 77-3 16 7 I II 73-7 171 7 7-4 171 6 Treatment group I II III - 3 -Tab le 2 .  Influence of Growth Rate from 3 to 12 Months of Age on Libido at 12 Months of Age Detection Intromission Ej aculation Treatment time a timeb timec group (minutes) (minutes) (minutes) I 3 . 4  2 . 8  4 . 8 II 1 . 9  2 . 0 4 . 7  III 1 . 9  1 . 8  5 . 7 a Detection time is the period of time from entering the pen until the boar located a gilt in es trus . b Intromission time is that period of time from detecting the gilt in es trus until gaining intromission . c Ej aculation time is that period o f  time from intromission until dismounting from the gilt . Table 3 .  Influence o f  Growth Rate From 3 to 12 Months of Age on Subsequent Fertility No . gilts pregnant No . embryos No . live per per per no . bred no . CL a no . CL a 14/14  175/205 ( 85 . 4%) 170/205 (82 . 9%) 11/12 138/158 ( 87 . 3%) 138/158 ( 87.3%) 10/11 141/163 ( 86 . 5%)  139/163 ( 85 . 3%) a CL implies corpus luteum which can be used to es timate the number o f  eggs shed ( ovulation) . 7 - 5 -400 , • / • / / , 300 , / / / # / ..a / r-1 / , .µ / / .c / 00 , "H / / Q) 200 / � , ;::>-, /,,,, / '"O 0 , / >=!:! �/ /-, // 100 �, Sept. Oct, Nov. Dec. Jan. Feb. Mar. Figure 1. Average body weights for individual treatment groups during the growing period. 8 I I I  I I  I 

Influence of Growth Rate from Three to Twelve Months of Age on Reproductive Characteristics of Boars

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Influence of Growth Rate from Three to Twelve Months of Age on Reproductive Characteristics of Boars

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