(Diss. Phil. II Bern : 1945).

Inaug.-Diss. Philos. Bern, 1975. / Zugl. als Sonderdruck erschienen. Bibliogr.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 159-170). Also available via the Internet.

Call number: LD2668 .T4 1985 K74 / Master of Science

The objectives of the current study were: 1) to examine serum bPAG concentration during pregnancy, and in the post-partum period in relation to the overall nutritional and metabolic status and post-partum anoestrous period; 2) to investigate bPAG decay models for postulating distribution and metabolism of bPAG in the blood circulation using half-life (t1/2) and to compare the t1/2 values between breeds and nutritional treatments for the clearance of bPAG; 3) to examine the suitability of the radioimmunoassay (RIA) for measuring bPAG in urine, saliva and milk, to investigate temporal relationships between bPAG in these fluids and that in the serum, and to assess the potential of bPAG in these fluids for pregnancy diagnosis in cows. Estimation of total bPAG disappearance from plasma per day during week 1 post-partum did not differ between the breeds. Urinary bPAG, over the same period of time, was lower for Welsh Black than Simmental and Charolais cows (0.45 vs 0.53 and 0.59 nmol (s.e.d 0.03) p<0.05) but not for Aberdeen Angus cows (0.48 nmol); bPAG in saliva was lower for Welsh Black than Charolais and Aberdeen Angus cows (1.65 vs 2.42 and 2.49 nmol (s.e.d 0.11) p<0.05) but not for Simmental cows (1.44 nmol/1), and bPAG measured in milk (whole) was lower for Charolais than Simmental cows (0.26 vs 0.47 nmol (s.e.d 0.06) p<0.05) but not for Aberdeen Angus (0.38 nmol/1) and Welsh Black cows (0.37 nmol/1). Total body elimination of bPAG in urine, saliva and milk accounted only for 5.28 % of the total plasma bPAG. Total body elimination of bPAG in urine, saliva and milk accounted for only 5.28 % of the total plasma bPAG. The remaining 94.72 % of bPAG may have been metabolished and was undetectable by the current RIA technique. A theoretical assessment for potential use of bPAG RIA for pregnancy diagnosis using urine, saliva and milk showed that the minimum detection limits of measuring bPAG in these fluids were reached and / or exceeded by Day 200 of gestation, or later. Consequently, assay of bPAG in these fluids for early pregnancy diagnosis would not be appropriate unless the sensitivity of the assays is improved considerably, or prior assay sample extraction/concentration is carried out.

The need for a more reliable method to select beef heifers to retain as replacement dams has become a concern in the beef industry. Two polymorphisms described in leptin (LEP), p.Arg25Cys, and pro-melanin concentrating hormone (PMCH), g.-134A>T, have already been shown to improve carcass quality in beef cattle. This study was designed to evaluate any additional advantages of these polymorphisms in terms of heifer conception and calving success and lactational milk yield measured indirectly by their calves’ early ADG while they were primarily on lactation. A dominant effect of the dam’s PMCH T allele was observed on improved calf early ADGs in Simmental heifer dams, although not in Angus heifer dams. This effect could be useful in cow-calf operations where calves were suckling their dams for a longer period before sending the cow-calf pairs out to summer pasture. The dam LEP genotype did not show an effect on their calves’ ADG. This was assumed to be due to low body fat reserves of the heifer dams at the age of two years, allowing for only low levels of leptin. Even though heifer conception was not affected by their LEP and PMCH genotypes, it would be worth evaluating their rebreeding success in the presence of these SNPs in the future. The Integral Membrane Protein 2A (ITM2A) was hypothesized as a candidate gene for frame size in cattle. DNA fragments from 20 cattle, matching the predicted exons of the cattle ITM2A gene, were sequenced to determine whether genetic variation existed. However, the sequence obtained based on the predicted cattle ITM2A sequences appeared to be a pseudogene, rather than the actual cattle ITM2A gene, because exons 1, 2, 3 and 5 contained stop codons. Since frame size has been reported to be associated with the reproductive performance of beef dams and their calves’ growth characteristics, it would be useful to characterize this gene once an improved cattle genome assembly is available.

Data from 946 Angus and 351 Simmental females were used to quantify relationships between calfhood and early-life traits of females with fertility in the first two breeding seasons, and with calf production in the first, in three and in eleven years of life. These traits were used to develop prediction equations for fertility using logistic regression methodology. For productive performance, three methodologies were compared: least squares, ridge regression and principal components regression. For heifers of both breeds, fertility was associated with birth date, weaning weight ratio and weaning-yearling relative growth rate (RGR). The only calfhood trait that consistently affected fertility in the second breeding season was birth weight of the cow. Fertility of first parity Simmentals was also associated with birth-yearling RGR. First calving season traits explained a higher proportion of variation in second breeding season fertility than calfhood traits of the cow. Among these traits, calving date, calving ease score and sex of the calf were the most important. The combination of birth date and weaning-yearling RGR produced the best models to predict heifer fertility for both breeds. Fertility in the second breeding season was best predicted for Angus cows when calving date, calving ease score and sex of the calf were used as regressors. For Simmental cows, fertility in the second breeding season was best predicted from birth weight of the calf and calving ease score. The regression of weaning weight of the first calf on pre-selected calfhood traits was used to evaluate models produced by least squares, ridge regression and principal components regression. Although biased, the regression coefficient estimates produced by ridge and principal components regression had smaller variances than estimates obtained from least squares. Between the two alternatives to least squares, ridge regression produced better results than principal components regression. Ridge and least squares regression were quite similar in their regression coefficient estimates, in prediction sum of squares (PRESS)-like statistics and, to a lesser extent, in conceptual predictive criteria (C_p)-like statistics. For prediction, the performance of models produced by least squares and by ridge regression were very similar. For analyses of the production traits, least squares regression models for all possible combinations of pre-selected regressor variables were fit. Birth date of the female was negatively associated with the weaning weight of the first calf, and with number of calves weaned, total weaning weight of calves produced and average weaning weight of calves in the first three years of productive life. Age of the dam affected early-life production traits of daughters, as well as the average weaning weight of calves produced per year of productive life and calf survival in eleven years. Heavier females at birth tended to produce smaller number of calves and lower calf weaning weight through their lives than females lighter at birth. Overall female productivity was consistently more positively associated with yearling than with weaning growth traits. Among traits observed in the first calving season, calving date, calving ease score, sex and weaning weight of the calf were associated with subsequent production. Weaning weight of the first calf was always positively associated and it was the most important variable to predict female production, except for survival rate. Prediction equations for production in three years included birth date, birth weight of the female, calving ease in the first parturition, sex of the calf and weaning weight of the first calf. This latter variable was the only one useful to predict production in eleven years. Average calf weaning weights in the first three years of production were best predicted using yearling weight ratio or weaning-yearling ADG and first calf weaning weight. Models including age of the female’s dam best predicted weaning weight of calves per year of productive life in eleven years and calf survival. / Ph. D.

No description available.

Thesis (MScAgric)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The objective of this study was to obtain more information regarding the characterisation of Afrikaner (A), Hereford (H) and Simmentaler (S) breeds in an initial crossbreeding programme and subsequent composite development. This involves the estimation of breed additive effects, breed maternal, individual heterotic effects and maternal heterotic effects in the initial crossbreeding phase and the estimation of genetic parameters and prediction of breeding values in later generations for birth weight (BW), weaning weight (WW) and cow efficiency (CE; WW/dam weight" 75 x 100) in an intensive environment under high stocking rates. In the analysis of the initial crossbreeding phase, the S breed direct effects, expressed as deviation from the general mean, were positive (P :s; 0.01) for both BW and WW. Hereford and A breed direct effects were negative (P :s; 0.01) for both BW and WW. Afrikaner direct maternal effects were positive (P :s; 0.01) for both BW and WW. The H direct maternal effect was negative (P :s; 0.05) (- 2.8%) for WW. Simmentaler maternal effect was negative (P :s; 0.01) for BW but non-significant (P ;:::0:.05) for WW. Individual heterotic effects for BW were significant (P:S; 0.01) in H x S (3.5%) and S x A (11.0%) only. Individual heterotic effects were positive (P :s; 0.01) for WW, with that of the H x A (9.8%) and S x A (6.7%) crosses exceeding the H x S (3.1%) cross. Maternal heterotic effects were non-significant (P ;:::0:.05) for both BW and WW. Investigations of the contributions of the A, Hand S during composite development in later generations, respectively, were made to estimate direct heritabilities (h2 a) and maternal heritabilities (h2 m) for BW and WW of the calf and CE of the dam. Calves were born between 1968 and 1993 (n = 52628). Calves of this composite population had varying levels of A, Hand S genes ranging from o to 75%, 0 to 100% and 0 to 96.9%, with an average of 4.3,19.3 and 33.4%, respectively. For the A, direct heritabilities fitting unitrait models were 0.67, 0.53 and 0.19 for BW, WW and CE, respectively, with corresponding estimates of h2mbeing 0.22, 0.36 and 0.58. Genetic correlations between direct and maternal effects (ram)were negative for all three traits, varying from -0.32 to - 0.62. Direct breeding values for BW increased and reached a maximum value at 0.11 proportion of A. The maternal breeding values for BW decreased linearly between 1.6 to 37.5% A proportion and increased linearly between 37.5 to 75% A proportion. For WW, the direct breeding values decreased linearly with increasing A proportion, while the maternal breeding values were not affected by proportion of A. Cow efficiency was unaffected by an increase in proportion of A. For the H, direct heritabilities fitting unitrait models were 0.67,0.52 and 0.21 for BW, WW and CE, respectively, with corresponding estimates of h2mbeing 0.22, 0.36 and 0.60. Genetic correlations between direct and maternal effects (ram)were negative for all three traits, varying from -0.32 to - 0.64. Direct breeding values and maternal breeding values for BW and WW decreased with increasing proportion of H. Direct breeding value for CE increased, while the maternal breeding value for CE reached minimum value at 0.62 proportion ofH. For the S, direct heritabilities fitting unitrait models were 0.66, 0.53 and 0.21 for BW, WW and CE, respectively, with corresponding estimates of h2m being 0.22, 0.36 and 0.59. Genetic correlations between direct and maternal effects (ram)were negative for all three traits, varying from -0.32 to - 0.63. Direct breeding values for BW and WW decreased and maternal breeding values increased with increasing proportion of S. Cow efficiency was unaffected by an increase in proportion of S. The study suggests that in the initial crossbreeding phase, purebred S breeding seems to be the best breeding practice for this environment and that during composite development, high A and H contributions could lead to low BW and WW (except the maternal contribution of the A for BW and WW). The advantage of the S lies more in the maternal contribution than in the direct contribution suggesting that the S is a large-framed maternal line rather than a terminal sire line. / AFRIKAANSE OPSOMMING: 'N WAARDEBEP ALING VAN DIE BYDRAE VAN DIE AFRIKANER, SIMMENTALER EN HEREFORD TYDENS KOMPOSIETE RASONTWIKKELING BY VLEISBEESTE: Die doel van die studie was om inligting aangaande die karakterisering van die Afrikaner (A), Hereford (H) en Simmentaler (S) rasse tydens die oorspronklike aanvangsfase van kruisteling en daaropvolgende komposiet ontwikkeling te verkry. Dit het die beraming van direkte additiewe, individuele heterose, direkte materne en materne heterotiese effekte tydens die aanvangsfase van die kruisteeltprogram, die beraming van genetiese parameters en die voorspelling van die teeltwaardes in latere generasies behels. Die eienskappe wat ingesluit is, is geboortegewig (BW), speengewig (WW) en koeidoeltreffendheid (CE; WW/koeigewigo.75 ). Hierdie kudde is in 'n intensiewe maar onder 'n hoë weidingsdruk omgewing aangehou. Tydens die ontleding van die eerste kruisteeltfase is die direkte additiewe effekte vir die S, uitgedruk as afwyking van die algemene gemiddelde, vir beide BW en WW positief (P ~ 0.01). Direkte additiewe effekte vir die H en A was vir beide BW en WW negatief (P ~ 0.01). Afrikaner materne effekte was vir beide BW en WW (P ~ 0.01) positief. Die H direkte materne effekte was negatief (-2.8%) (P ~ 0.05) vir WW. Simmentaler maternal effekte was ook vir BW negatief (P ~ 0.01), maar nie-betekenisvol (P 20.05) vir WW. Individuele heterose was slegs betekenisvol (P ~ 0.01) vir kombinasies van H x S (3.5%) en S x H (11.0%) vir BW. Individuele heterose was positief (P ~ 0.01) vir WW waar H x A (9.8%) en S x A (6.7%) kruisings dié van die H x S (3.1%) kruising oortrefhet. Materne heterose was vir beide BW en WW nie-betekenisvol (P 2 0.05). Die relatiewe bydraes van die A, H en S is ook tydens komposiet-ontwikkeling bereken. Direkte additiewe oorerflikhede (h2 a) en materne oorerflikhede (h2m) is vir BW en WW van die kalf en CE van die koei beraam. Kalwers in die komposiet kudde, gebore tussen 1968 en 1993 (n = 52628), het variërende vlakke van A, H en S gene. Die samestelling het gevarieer van 0 - 75%, 0 - 100% en 0 - 96.9%, met 'n gemiddeld van 4.3, 19.3 en 33.4%. Vir die A was die direkte erfbaarhede (h2 a), soos deur die passing van 'n enkeleienskapmodel beraam, 0.67, 0.53 en 0.19 vir onderskeidelik BW, WW en CE, met ooreenstemmende beramings van 0.22, 0.36 en 0.58 vir h2 rn- Genetiese korrelasies tussen direkte en mateme effekte (ram)was almal negatief en het tussen -0.32 en -0.62 gewissel. Direkte teelwaardes vir BW het met toenemende A-bydrae gestyg en het 'n maksimum waarde by 0.11 bereik. Die mateme teelwaardes vir BW het lineêr gedaal tussen 1.6 en 37.5% A-bydrae en het weer lineêr tussen 37.5 en 75% Abydrae gestyg. Vir WW het die direkte teelwaardes lineêr met toenemende A-bydrae gestyg, terwyl die mateme teelwaardes nie deur A-bydrae beïnvloed was nie. Koeidoeltreffendheid was nie deur 'n toename in A-bydrae beïnvloed nie. Vir die H was die direkte erfbaarhede (h2 a), soos deur die passing van 'n enkeleienskapmodel beraam 0.67, 0.52 en 0.21 vir onderskeidelik BW, WW en CE, met ooreenstemmende beramings van 0.22, 0.36 en 0.60 vir h2 rn- Genetiese korrelasies tussen direkte en mateme effekte (ram)was almal negatief en het tussen -0.32 en -0.64 gewissel. Direkte teelwaardes en mateme teelwaardes vir BW en WW het met toenemende H-bydrae gedaal. Direkte teelwaarde vir CE het ook met toenemende If-bydrae gedaal, terwyl die mateme teelwaarde 'n minimum waarde by 0.62 H-bydrae bereik het. Vir die S was die direkte erfbaarhede (h2a), soos deur die passing van 'n enkeleienskapmodel beraam 0.66, 0.53 en 0.21 vir onderskeidelik BW, WW en CE, met ooreenstemmende beramings van 0.22, 0.36 en 0.59 vir h2 m- Genetiese korrelasies tussen direkte en mateme effekte (ram)was almal negatief en het tussen -0.32 en -0.63 gewissel. Direkte teelwaardes vir BW en WW het gedaal, terwyl die mateme teelwaardes met toenemende S-bydrae gestyg het. Koeidoeltreffendheid was nie deur 'n toename in S-bydrae beïnvloed nie. Die bevinding was dat tydens die ontleding van die eerste kruisteeltfase die teling van suiwer S aanbeveel word en dat tydens komposiete-ontwikkeling toenemende A- en H-bydraes neig om aanleiding te gee tot afnames in BW en WW (behalwe die mateme bydrae van die A vir BW en WW). Die S-bydrae se voordeel is meer in die mateme bydrae as in die direkte bydrae geleë en dui dus aan dat die S as 'n mateme grootraam lyn i.p.v. as 'n terminale bullyn gebruik moet word.

Tiriamasis darbas buvo atliktas 2013 metais Lietuvos sveikatos mokslų universiteto Veterinarijos akademijos Gyvulininkystės katedroje. Bandymas buvo atliktas X ūkyje, esančiame Kėdainių rajone. Tyrimui naudota 20 holšteinų veislės karvių ir 20 simentalų x holšteinų F1 kartos mišrūnių. Visi gyvuliai antros laktacijos ir veršiavosi 2013 m. sausio – vasario mėn. Gyvuliai stebėti ir duomenys apie jų produktyvumą registruoti ir vertinti vienerius metus – nuo 2013 m. sausio 1 d. iki 2013 m. gruodžio 31 d. Darbo tikslas – atlikti pieninių simentalų mišrūnių ir holšteinų veislės karvių produkcijos rodiklių ir somatinių ląstelių skaičiaus piene palyginamąją analizę laktacijos eigoje. Uždaviniai: 1. Įvertinti ir palyginti pieninių simentalų mišrūnių ir holšteinų veislės karvių pieno sudėties rodiklius: primelžto pieno kiekį, baltymų, riebalų, laktozės ir urėjos kiekius piene. 2. Įvertinti ir palyginti somatinių ląstelių skaičių piene tarp pieninių simentalų mišrūnių ir holšteinų veislių karvių. 3. Palyginti abiejų veislių parduodamo pieno ekonominius rodiklius. 4. Palyginti pieninių simentalų mišrūnių ir holšteinų veislės karvių mėsos produktyvumo kokybinius ir kiekybinius rodiklius (parduodamų karvių gyvą svorį ir mėsos išeigą), taip pat atlikti abiejų veislių, ekonominį parduodamos mėsos vertinimą. Tyrimo metu nustatyta, kad vidutiniai primilžiai (simentalų mišrūnių – 8951,0 litrų, holšteinų – 8665,7 litrų) metų laikotarpyje buvo panašūs tarp abiejų veislių, tačiau pieninių... [toliau žr. visą tekstą] / Research was done in the Department of Animal Husbandry in the Veterinary Academy of the Lithuanian University of Health Sciences in the year 2013. Experiment was done in the X farm, located in Kedainiai region, Josvainiai district. 20 holstein cows and 20 simmental-holstein F1 generation hybrids were used for the research. All livestock was from the second lactation and were calving in November-December 2012. Livestock was observed and productivity data was registered and evaluated for one year: from 1st of January till 31st of December in 2013. Objective of the research – to perform comparable analysis of dairy simmental hybrids and holstein cows’ milk production composition and quality rate during lactation. Tasks: 1. To compare milk-producing simmental hybrids and holstein cows’ milk production productivity‘s quality and quantity rates: amount of milk yield, milk proteins, fats, lactose amount, number of somatic cells in the milk, amount of urea. 2. To compare milk-producing simmental hybrids and holstein cows’ meat productivity quality and quantity rates: meat weight and carcase mass. 3. To calculate financial rates of milk-producing simmental hybrids and holstein cows’ meat and milk. During the research it was stated that yield (simmental hybrids: 8951.0 l., holstein: 8665.7 l.) during the year was similar in both stocks (no essential differences have been found), but average annual amount of milk fat (0.32 percent unit) and protein (0,2 percent unit) in simmental... [to full text]