A deterministic model is used to analyze the genetic properties of a two tier dairy cattle open nucleus breeding system proposed in developing countries. Theoretical selection response rates are adjusted to account for the effects of population size and structure, selection disequilibrium, sampling losses, inbreeding, and planning horizon. Optimized nucleus progeny testing, adult or juvenile multiple ovulation and embryo transfer in sib or pedigree testing schemes are used in the nucleus. All sires come from the nucleus. Females in the base herds may be recorded and selected as bull dams or donor cows in the nucleus. The predicted genetic means in the base after a given planning horizon (20 years) for a range of situations studied, is generally highest for adult sib testing, but is higher for nucleus progeny testing than for juvenile pedigree testing schemes. The genetic means are higher with more females in the nucleus and with higher reproductive and embryo transfer success rates. The genetic level of the base is higher with higher fractions of nucleus dams born in the base, but is little affected by the proportion of the total population included in the nucleus. The genetic responses are also reduced when heritability in the base is lower than in the nucleus. Policies on the formation and running of an efficient open nucleus breeding system are discussed. Key words: nucleus breeding schemes, nucleus progeny testing, multiple ovulation and embryo transfer, genetic improvement. ZUSAMMENFASSUNG: Deterministische genetische Analyse eines offenen Nukleussystems für Milchrinder in Entwicklungsländern Ein deterministisches Modell wurde zur Analyse der genetischen Eigenheiten eines "Zwei-Stufen offenen Nukleuszuchtsystem" für Milchrinder für Entwicklungsländer verwendet. Theoretische Selektionserfolgsraten unter Berücksichtigung der Wirkungen von Populationsgröße und Struktur, Selektionsungleichgewicht, Zufallsschwankungen, Inzucht und Planungszeitraum für optimierte Nukleusnachkommenschaftsprüfung, adulte oder juvenile multiple Ovulation und Embryotransfer mit Geschwister- oder Pedigreeprüfungsplänen werden berechnet. Alle Vatertiere kommen von Nukleus, Muttertiere in den Basisherden z. T. leistungsgeprüft werden als Bullenmütter oder Spenderkühe im Nukleus verwendet. Das für die Basis geschätzte genetische Leistungsniveau eines gegebenen Planungshorizonts (20 Jahre) wird für eine Reihe von Situationen untersucht und ist im allgemeinen am höchsten für adulte Geschwisterprüfungssysteme, aber höher für Nukleusnachkommenschaftsprüfung als für juvenile Pedigreeprüfungspläne. Genetische Fortschritte sind höher, wenn mehr weibliche Tiere im Nukleus und höhere Reproduktions- und Transfererfolgsraten existieren. Das genetische Niveau der Basis ist höher, wenn ein höherer Anteil von Nukleusmuttertieren aus der Basis stammt, aber es wird wenig vom Nukleusanteil der gesamten Population tangiert. Der genetische Fortschritt wird reduziert, wenn Rentabilität in den Basisherden niedriger als im Nukleus ist. Die Strategien zur Bildu...

Selection response rates are predicted for nucleus progeny testing, adult multiple ovulation and embryo transfer (MOET) sib testing, and juvenile MOET pedigree testing in closed populations. Deterministic models are adapted to adjust predicted genetic gains for the effects of population size and structure, selection disequilibrium, sampling losses, and inbreeding depression. The improvement schemes were optimized for different numbers of sires used and first lactation females recorded per year. The number of nucleus daughters tested per sire, and of females per MOET full sibship, that maximize the predicted response to selection per year, were determined. Annual genetic gains and inbreeding rates were interpolated to the same planning horizon (20 years) to compare the optimized schemes for a wide range of situations. The predicted maximum genetic gain per year is higher for adult MOET than for juvenile MOET (due to the proportional extra time to collect the embryos needed) and for nucleus progeny testing. Average annual inbreeding rates are much higher for MOET schemes than for nucleus progeny testing. The advantages of adult and juvenile over nucleus progeny testing are little affected by planning horizon, but are higher with more females recorded per year, higher heritability, and higher reproductive and MOET success rates. Comparison of the schemes at the same level of inbreeding is fairer for fixed testing resources. At the same inbreeding level, the genetic advantage of adult MOET was generally maintained, but juvenile MOET then lost its advantage over progeny testing in these closed populations. ZUSAMMENFASSUNG: Optimierte Prüfpläne für Nukleusnachkommen, adulte MOET Geschwister oder juvenile MOET Pedigrees in geschlossenen Milchviehpopulationen Selektionserfolge werden für Nukleusnachkommenprüfung, adulte multiple Ovulation (MOET) und Embryotransfer, Geschwisterprüfung und juvenile MOET Pedigreeprüfung geschlossener Populationen geschätzt. Deterministische Modelle werden modifiziert zur Berücksichtigung geschätzter genetischer Fortschritte für die Wirkungen von Populationsgröße, Struktur, Selektionsungleichgewicht, Stichprobenungenauigkeit und Inzuchtdepression. Die Zuchtpläne werden für verschiedene Zahlen von Stieren und Erstlaktationskühe pro Jahr optimiert. Die Zahl der geprüften Nukleustöchter je Stier und Kühe je MOETVollgeschwistergruppe, die den geschätzten Erfolg maximieren, werden bestimmt. Um die optimierten Pläne über einen weiten Bereich zu vergleichen, werden jährlicher Zuchtfortschritt und Inzuchtzuwachs für den gleichen Planungshorizont von 20 Jahren interpoliert. Der geschätzte maximale Zuchtfortschritt pro Jahr ist für adultes MOET höher als bei juvenilem (wegen zusätzlicher Zeit zur Embryonengewinnung) und bei Nukleusnachkommenschaftsprüfung. Durchschnittliche jährliche Inzuchtraten sind viel höher für MOET Pläne als für das Nachkommenschaftsprüfsystem. Die Vorteile des adulten und juvenilen MOET über Nukleusnachkommenprüfung werden durch den Planungshorizont nur geringfügig tangiert, we...

Karyotype analysis was carried out on blood samples of 30 water buffaloes belonging to different breed groups (i.e.Philippine Carabao (PC), Indian Murrah (IM), Bulgarian Murrah (BM), "F 1 50% IM-50% PC", "F 1 50% BM-50% PC" and "75% IM-25% PC"), using the modified Leucocyte Culture Technique. The modal chromosome numbers of the PC, "F 1 50% IM-50% PC", "F 1 50% BM-50% PC", IM, BM and "75% IM-25% PC" were 2n=48, 49, 49, 50, 50 and 50, respectively. The water buffalo chromosomes are mostly acrocentric (79.67%) and the remainder submetacentric (20.33%). Results of the ordinary least square analysis showed significant breed effects (p<0.01) on other karyotypic characteristics (i.e. relative length, arm ratio and centromeric index). Significant correlation between karyotypic characteristics and some animal performance traits were also found. The significant correlation values imply that karyotypic characteristics can be used as important criteria to select potentially productive young water buffaloes. In the future, more production and reproduction traits from non-institutional herds should be included in the analysis to reveal meaningful correlations with various karyotypic characteristics.

This study compared the composition, yield, and freezing point of buffalo colostrum and milk collected on the 30 th , 60 th , and 90 th day of lactation from purebred Murrah and its crosses with the Philippine Carabao. A total of 133 milk samples were collected from 36 buffaloes (20 purebred Murrah and 16 "Murrah x Carabao" crosses) and evaluated for fat, protein, and lactose content, solids non-fat (SNF), total solids, and freezing point. Colostrum contained significantly (p<0.05) more protein, SNF, total solids, and higher freezing point, but less moisture and lactose, and were produced in lower amounts than milk obtained on different days of lactation. Fat percentage was not significantly different (p>0.05) between colostrum and milk. Colostrum from Murrah buffaloes had more protein but less fat and colostrum yield than "Murrah x Carabao" crosses. Among crossbred buffaloes, the F2 "75% Murrah -25% Carabao" crosses produced more colostrum than F1 "50% Murrah -50% Carabao" (p<0.05). Older buffaloes also produced more colostrum. Milk parameters were similar for Murrah and "Murrah x Carabao" crosses, except for test-day milk yield, which was significantly higher in "Murrah x Carabao" crosses. The F1 crossbred buffaloes had milk containing more lactose and SNF, but lower freezing point than milk from F2 crossbred buffaloes. Buffaloes, already with more lactations, had higher test-day milk yield but with lower fat and total solids. High monthly temperature reduced test-day milk yield. In conclusion, breed differences, age at calving, number of lactations, and high monthly temperature may have caused changes in the composition and yield of buffalo colostrum and milk.

Information on the reasons for sow removal is limited and often unreported for nucleus breeding farms. This study analyzed the distribution of culling type (planned vs. unplanned) and culling reasons in relation to longevity -parity at culling (PAC) and productive herd life (PHL), and lifetime efficiency -lifetime pigs born alive (LPBA) and total pigs weaned (TPW) using data recorded from 2017 to 2019 by a local nucleus breeding farm. The study revealed a considerable amount of unplanned removal (84.1%) compared to planned culls, which is due to old age (11.4%) and poor farrowing performance (4.6%). The most common reasons for unplanned sow removal were reproductive failures (26.2%) and health disorders (23.4%), followed by physical defects (15.3%), leg/foot problems (10.8%), and mortality (8.5%). A high proportion (22.1%) of sows was culled at their first parity. The proportion of culled sows decreased up to parity 4, especially for unplanned sow removals due to reproductive failures, leg/foot problems, and mortality. Unplanned culling corresponded to lower PAC (3.8), PHL (459 days), LPBA (14.1 pigs/year), and TPW (12.4 pigs/year). Average PAC and PHL were significantly higher (p<0.05) for Large White sows (PAC= 5.2; PHL= 696 days) than Landrace sows (PAC= 4.6; PHL= 588 days). However, the LPBA and TPW were not significantly different between breeds. Information about sow removal could be used to develop management strategies to avoid unplanned culling in purebred sows and extend their productive life.