Analysis of the Relationships Between Type Traits and Longevity in Croatian Simmental Cattle Using Survival Analysis

Survival analysis with a Weibull proportional hazards model was used to evaluate the effect of linear type traits on the longevity in Croatian Simmental cattle. The data set consisted of 8,212 registered Simmental cows that first calved from 1997 to 2008. Longevity was defined as the number of days between first calving to culling or censoring. Cows alive at the end of the study (13.6%) were treated as right censored. Type information consisted of 19 linear type traits (with a nine-point scoring range) scored in the first lactation. Linear type traits were classified into four groups: muscularity, size traits, form traits and udder traits. The Weibull model included the time-independent effects of age at first calving, classifier, region and each type trait. The results showed a significant effect of 12 type traits on longevity. Among the form traits, low angled pasterns and extremely straight rear leg side view showed almost 2.0 times higher culling risks than normal posture. Cows with higher scores for the muscularity were at higher culling risk levels compared to lower scores. In the group of size traits, only rump height and body depth had significant impact on longevity. Lower scores for fore udder length were associated with lower risk of culling. In contrary, cows with lower scores for udder depth, suspensory ligament, rear udder length and teats thickness had higher probability of culling than the animals with higher scores

PRINCIPLES OF ANIMAL BREEDING

Sveučilišni udžbenik Principi uzgoja životinja namijenjen je studentima poljoprivrede i veterine. Gradivo je prilagođeno nastavnom programu preddiplomske i diplomske razine studija, u sklopu kojega se sluša modul Principi uzgoja životinja, kao i modul Osnove genetike i selekcije životinja. Udžbenik sadrži 14 poglavlja i rječnik pojmova. Koncepcija udžbenika je takva da na uravnotežen i kvalitetan način objedinjava temeljna znanja i suvremene spoznaje iz područja uzgoja i selekcije životinja. Gradivo udžbenika obuhvaća nekoliko cjelina. Prva cjelina odnosi se na klasične pojmove iz uzgoja domaćih životinja, kao što su povijest uzgoja domestikacija, pojam i podjela pasmina, nasljedna i nenasljedna varijabilnosti te upoznavanje s općim i proizvodnim svojstvima domaćih životinja. Druga cjelina odnosi se na osnovne pojmove u populacijskoj i kvantitativnoj genetici, kao i biometriji. Treća cjelina odnosi se na principe selekcije i oplemenjivanja domaćih životinja. Četvrta se cjelina odnosi na suvremene spoznaje i ciljeve upotrebe molekularnih markera u selekciji i uzgoju domaćih životinja. Iako se navedeno gradivo predaje na hrvatskim sveučilištima, do sada nije bilo prikazano u obliku jedinstvenoga udžbenika. Ministarstvo znanosti, obrazovanja i sporta Republike Hrvatske odobrilo je financijsku potporu za objavljivanje udžbenika.University textbook Principles of Animal Breeding is intended for students of agriculture and veterinary medicine. The material is the adapted curricula of undergraduate and graduate level studies in the framework of which the modules Principles of animal breeding as well as Basics of genetics and selection of animals attended are listened. The textbook contains 14 chapters and a glossary of terms. Its concept enables combining fundamental and modern knowledge in the breeding and selection of animals based on balanced and quality manner. The textbook material can be divided into several thematic sections. The first one relates to the classical notions of domestic animals breeding such as the history of breeding, domestication, breed, hereditary and non-hereditary variability and description of general and production traits. The second section focuses on the basic concepts in population and quantitative genetics, as well as biometrics. The third unit is dedicated to the principles of selection and domestic animals improving. The fourth unit relates to the current concepts and objectives of the molecular markers use in domestic animals selection and breeding. The above material has been submitted to the Croatian universities, but so far it has not been published as a textbook. The Ministry of Science, Education and Sports of Republic of Croatia approved financial support for the textbook publication

CORRELATION OF FEED INTAKE AND PRODUCTION CHARACTERISTICS OF BOARS IN A PERFORMANCE TEST

This paper deals with the influence of the level of feed on the results of the performance test of Large White boars between 30 and 100 kg live weight The test was performed through three years on three different farms including a total of 320 boars. The average production results were as follows: the age of boars at the beginning of the test was 87.07 days, the age at the end of the test was 165-61 days, daily weight gain 0.904 kg, daily feed intake 2.30 kg, conversion ratio 2.55 kg and the average thickness of bacon was 16.34 mm. To appraise of the influence of the systematic factors of the environment at the tested characteristics of the boars the analysis of the variation according to the LSQ method was used. The production characteristics of the boars were reviewed for each farm separately. The phenotype affinity between the fattening indicators is determined by the correlation coefficients. The higher daily feed consumption on all three farms was connected with a shorter fattening period (r=-0.46**, -0.51**, -0.44**), with a higher daily wight gain (r=0.47**, 0.36*, 0.46*) and a higher feed conversion ratio (r=0,40*, 0,47**, 0.45*). The results show a significant influence of the level of feed intake to the phenotype declared indicators of boars production and could be used in the breeding

ANALIZA ODNOSA IZMEĐU PRVE TRI LAKTACIJE U HOLSTEIN KRAVA

The objective of this study was to evaluate relationship between milk yield in the first three lactations regarding levels of milk yield in the first lactation and levels of age at the first calving. Prediction of milk yield in later lactation based on milk yield in the earlier one was also carried out. The data used in this study were 5743 lactation yields collected from 1995 to 2003. All cows finished the first three lactations. Mean value of milk yield in the first lactation was 5283.5 kg, 6033.5 kg in the second and 6338.4 kg the third one. The milk yield estimation coefficients between the first and second lactation was 1.164, between the first and third was 1.231, and 1.079 between the second and third. The levels of milk yield in the first lactation highly significant influenced the value of estimation coefficient between first three lactations, while the age at first calving influenced less significantly. Determination coefficient (R2) values for models used in prediction ranged from 0.348 to 0.396.Cilj istraživanja bio je utvrditi odnos između količine mlijeka u prve tri laktacije krava Holstein pasmine, uz uvažavanje razine mliječnosti u prvoj laktaciji i dobi pri prvom teljenju te procijeniti količinu mlijeka u kasnijim na temelju količine mlijeka u ranijim laktacijama. Korišteni su podaci o količini mlijeka 5743 krava, koje su u razdoblju od 1995. – 2003. završile prve tri laktacije. Prosječna količina mlijeka u prvoj standardnoj laktaciji bila je 5283,5 kg, u drugoj 6033,5 kg te 6338,4 kg u trećoj laktaciji. Prosječna vrijednost koeficijenata procjene između prve i druge laktacije bila je 1,164, prve i treće 1,231 te druge i treće 1,079. Utvrđene su statistički visoko signifikantne razlike između koeficijenata procjene pri uvažavanju razine mliječnosti u prvoj laktaciji, dok je utjecaj dobi pri prvom teljenju bio manje signifikantan. Vrijednosti koeficijenata determinacije (R2) modela za procjenu količine mlijeka u kasnijoj laktaciji na osnovu ranije kretali su se od 0,348 do 0,396

ANALIZA ODNOSA IZMEĐU PRVE TRI LAKTACIJE U HOLSTEIN KRAVA

The objective of this study was to evaluate relationship between milk yield in the first three lactations regarding levels of milk yield in the first lactation and levels of age at the first calving. Prediction of milk yield in later lactation based on milk yield in the earlier one was also carried out. The data used in this study were 5743 lactation yields collected from 1995 to 2003. All cows finished the first three lactations. Mean value of milk yield in the first lactation was 5283.5 kg, 6033.5 kg in the second and 6338.4 kg the third one. The milk yield estimation coefficients between the first and second lactation was 1.164, between the first and third was 1.231, and 1.079 between the second and third. The levels of milk yield in the first lactation highly significant influenced the value of estimation coefficient between first three lactations, while the age at first calving influenced less significantly. Determination coefficient (R2) values for models used in prediction ranged from 0.348 to 0.396.Cilj istraživanja bio je utvrditi odnos između količine mlijeka u prve tri laktacije krava Holstein pasmine, uz uvažavanje razine mliječnosti u prvoj laktaciji i dobi pri prvom teljenju te procijeniti količinu mlijeka u kasnijim na temelju količine mlijeka u ranijim laktacijama. Korišteni su podaci o količini mlijeka 5743 krava, koje su u razdoblju od 1995. – 2003. završile prve tri laktacije. Prosječna količina mlijeka u prvoj standardnoj laktaciji bila je 5283,5 kg, u drugoj 6033,5 kg te 6338,4 kg u trećoj laktaciji. Prosječna vrijednost koeficijenata procjene između prve i druge laktacije bila je 1,164, prve i treće 1,231 te druge i treće 1,079. Utvrđene su statistički visoko signifikantne razlike između koeficijenata procjene pri uvažavanju razine mliječnosti u prvoj laktaciji, dok je utjecaj dobi pri prvom teljenju bio manje signifikantan. Vrijednosti koeficijenata determinacije (R2) modela za procjenu količine mlijeka u kasnijoj laktaciji na osnovu ranije kretali su se od 0,348 do 0,396

Analysis of the Relationships Between Type Traits and Longevity in Croatian Simmental Cattle Using Survival Analysis

Survival analysis with a Weibull proportional hazards model was used to evaluate the effect of linear type traits on the longevity in Croatian Simmental cattle. The data set consisted of 8,212 registered Simmental cows that first calved from 1997 to 2008. Longevity was defined as the number of days between first calving to culling or censoring. Cows alive at the end of the study (13.6%) were treated as right censored. Type information consisted of 19 linear type traits (with a nine-point scoring range) scored in the first lactation. Linear type traits were classified into four groups: muscularity, size traits, form traits and udder traits. The Weibull model included the time-independent effects of age at first calving, classifier, region and each type trait. The results showed a significant effect of 12 type traits on longevity. Among the form traits, low angled pasterns and extremely straight rear leg side view showed almost 2.0 times higher culling risks than normal posture. Cows with higher scores for the muscularity were at higher culling risk levels compared to lower scores. In the group of size traits, only rump height and body depth had significant impact on longevity. Lower scores for fore udder length were associated with lower risk of culling. In contrary, cows with lower scores for udder depth, suspensory ligament, rear udder length and teats thickness had higher probability of culling than the animals with higher scores