Maternal traits in Brangus cattle

TitleMaternal traits in Brangus cattle
Publication TypeThesis
Year of Publication1975
AuthorsCruz-Mendoza J
Number of Pages101
Date Published1975
UniversityNew Mexico State University
CityLas Cruces, New Mexico
Thesis TypeM.S. Thesispp
Call Number00487
Keywordscattle, management, cattle, productivity, cattle, reproduction, dissertation, dissertations, theses, thesis
AbstractProduction records of two Brangus commercial straightbred herds were used in this research to study the maternal traits of Brangus cattle under semidesert range conditions. Data were collected from a total of 97 cows including 40 cows from Ladder Ranch (herd I), and 57 cows which were born on the College Ranch (herd II) at New Mexico State University between 1965 and 1974. Both reproductive and productive performance traits were studied in terms of calf crop born, weaned, and number of pounds of calf weaned per cow per year. Weaning weight (actual and adjusted at 205 days of age) was considered as the dependent variable, and was assumed to be affected by dam, year, sex of calf at weaning, and fall dam weight as independent variables. Dam, year and age of calf approached a highly significant effect (P<.01 on="" weaning="" weights="" of="" calves="" out="" both="" herds="" except="" the="" day="" adjusted="" weight="" from="" herd="" i.="" effect="" calf="" sex="" was="" highly="" significant="" in="" where="" actual="" concerned="" and="" weight.="" male="" exceeded="" females="" by="" pounds="" i="" dan="" ii="" for="" respectively.="" fall="" dam="" had="" a="" nonsignificant="">.05) on weight of calves weaned out of herd dams. Calving intervals were analyzed in two ways: one using only the interval between calves in consecutive years and then by using all intervals. Calving interval was considered to be influenced by dam, year, sex of initial calf, and linear and quadratic effects of calving date of initial calf. Dam had a significant effect(P<.1 on="" calving="" interval.="" year="" had="" a="" statistically="" highly="" significant="" effect="" in="" herd="" i="" and="" ii.="" sex="" of="" calf="" at="" side="" was="" non-significant="">.1) for either herd and for either calving interval range. Calf birth date had neither linear or quadratic effects (P>.1) in either herd. Repeatability values of weaning weight and calving interval were estimated. Within herd repeatability values for actual weaning weight for herds I and II, respectively, were 0.3815 and 0.2484. Similar values for adjusted weaning weight were 0.3702 and 0.2484. Pooled estimates were 0.2542 and 0.3522 for actual and adjusted weaning weights, respectively. Within herd and pooled repeatability values of calving interval were zero using only consecutive year calves. For all calves repeatability was 0.203 and zero for herds I and II, respectively, while pooled the pooled value was 0.041. Weight of herd II dams was considered to be influenced by dam, year, season, season x year, and sex of calf and lactation status of dam (dry or wet). Dam weights in the fall were significantly affected (P<.01 by="" dam="" year="" season="" and="" sex="" of="" calf.="" x="" interaction="" was="" a="" significant="" source="" variation="" on="" weight="">