The performance of Brahman-Shorthorn and Sahiwal-Shorthorn beef cattle in the dry tropics of northern Queensland. 1. Reproductive rates and liveweights of F1 and backcross females

1990 ◽  
Vol 30 (6) ◽  
pp. 717 ◽  
Author(s):  
RG Holroyd ◽  
TA James ◽  
VJ Doogan ◽  
G Fordyce ◽  
PK O'Rourke

A breeding program was established at Swan's Lagoon Beef Cattle Research Station in the dry tropics of northern Queensland to evaluate the productivity of cattle which were genotypically at least one-half Bos indicus. Brahman or Sahiwal bulls were initially mated to B. taurus cows (predominantly Shorthorn) to produce the first filial generation (F1 1/2 Brahman and F1 1/2 Sahiwal). First backcross 314 Brahman and first backcross 314 Sahiwal were derived from crossing F1 1/2 Brahman or F1 1/2 Sahiwal cows to their respective sire breeds. This paper reports on the female reproductive rates and liveweight performance in 2 data sets: 1972-79, F1 1/2 Brahman v. F1 1/2 Sahiwal; 1975-83, first backcross 3/4 Brahman v. first backcross 3/4 Sahiwal. In both data sets, significant differences in fertility (pregnancy rate and calving date) between F1 or first backcross groups were infrequent, and where differences did occur, they were often inconsistent due to cross x year interactions. The difference between weaning rates and pregnancy rates (representing foetal and calf wastage) was 5 percentage units higher in Sahiwal crosses than Brahman crosses for lactating cows Year effects significantly (P<0.05) influencd both fertility and liveweight, demonstrating the extent of seasonal influences on cattle production in the dry tropics. Generally Brahman-cross cows were heavier throughout than their Sahiwal counterparts. Among lactating cows, F1 1/2 Brahman were 21 kg heavier at start of mating than F1 1/2 Sahiwal, while first backcross 3/4 Brahman were 29 kg heavier than first backcross 3/4 Sahiwal.

1990 ◽  
Vol 30 (6) ◽  
pp. 727 ◽  
Author(s):  
RG Holroyd ◽  
TA James ◽  
VJ Doogan ◽  
G Fordyce ◽  
R Tyler ◽  
...  

The female reproductive rates and liveweight performance of F2 et seq. generations of 1/2 Brahman (1/2 B), 1/2 Sahiwal (1/2 Sah), 3/4 Brahman (3/4 B) and 3/4 Sahiwal (3/4 Sah) were evaluated in the dry tropics of northern Queensland from 1978 to 1986. The balance of the breed composition was predominantly Shorthorn. A preliminary comparative analysis of F2 and F3 data showed no differences between the filial generations and data were subsequently pooled. Crossbreed differences between groups had a small effect on pregnancy rate and were not a major determinant of fertility compared with age and year effects. Any crossbreed differences were counteracted by inconsistent cross x year effects. For mature cows, 3/4 Sah had significantly (P<0.05) lower weaning rates than other crosses. The percentage unit difference between pregnancy rate and weaning rate was higher in Sahiwal cross than Brahman cross cows (19 v. 9%). In lactating cows, calving dates were an average 10 days later in 3/4 than 1/2 Bos indicus cows. Generally Brahman crosses were heavier than Sahiwal crosses. In the dry season, Brahman crosses were 16, 30, 36 and 43 kg heavier than Sahiwal crosses for 2-year-old heifers and 3-, 4- and 5-9-year-old cows, respectively. There was little difference between 1/2 and 3/4 B. indicus, except in mature cows, where 1/2 Sah were 27 kg heavier (P<0.05) than 3/4 Sah at start of mating. There were pronounced year effects on all of the reproductive and growth parameters of both heifers and lactating cows. Pregnancy rate and mating liveweight were negatively correlated with date of seasonal break of the dry season (r = -0.71 to -0.88, r = -0.84 to -0.98, respectively). Cross x year interactions for pregnancy rate, calving date and mating liveweight were attributed to factors other than the type of year.


1987 ◽  
Vol 38 (2) ◽  
pp. 427 ◽  
Author(s):  
G Fordyce ◽  
RG Holroyd ◽  
NJ Beaman ◽  
TA James ◽  
D Hoffmann ◽  
...  

Epitheliogenesis imperfecta (EI) has been diagnosed in calves on a north Queensland beef cattle research station. There are five Bos indicus cross, inter se mated breed groups on the station: 1/2 Brahman, 3/4 Brahman, 1/2 Sahiwal, 3/4 Sahiwal and High Grade Sahiwal. The disease was confined to the three Sahiwal breed groups and caused calf losses over seven years from 1978 of 0.2%, 3.4% and 1.0% in the 1/2, 3/4 and High Grade groups respectively. The Sahiwal breed was identified as the origin of the gene responsible for the disease. The source of the gene within the Sahiwal breed was investigated, and several ancestors were identified as almost certainly being heterozygotes. Analyses of relationships of affected and non-affected calves to the 10 Sahiwals that were originally imported into Australia identified the one that was most likely the source of the El gene.


2011 ◽  
Vol 51 (6) ◽  
pp. 529 ◽  
Author(s):  
R. M. Dixon ◽  
C. Playford ◽  
D. B. Coates

In the seasonally dry tropics the effects of three times of weaning and three nutritional regimes on the changes in liveweight (LW) and body condition score (BCS) of grazing Bos indicus × Bos taurus breeder cows (n = 210) and their calves were examined through an annual cycle, commencing in the early dry season in April 1998. Most of the cows (n = 180) were lactating initially, and were weaned in April (W1), July (W2) or September (W3) to represent the expected early, mid and late dry season. In addition, cows that had not lactated for 11 months before the experiment commenced (NOCALF treatment; n = 30) were examined. The seasonal break occurred in late August, 3.5 months earlier than average for the site. The nutritional regimes consisted of a native pasture (LOW), another native pasture augmented with Stylosanthes spp. legumes (MEDIUM), or this latter pasture supplemented during the dry season with molasses-urea (HIGH). These nutritional regimes were imposed from the commencement of the experiment in April 1998 until February 1999, except that for the HIGH treatment the supplement was fed only during the dry season. Near-infrared reflectance spectroscopy of faeces (F.NIRS) was used to estimate the contents of non-grass, crude protein (CP) and DM digestibility of the diet selected, and also DM intake and metabolisable energy (ME) intake. Diet quality was in accord with the expected seasonal cycle, and was consistently lower (P < 0.05) for the LOW than for the MEDIUM treatment. Concentrations of CP and CP/MJ ME in the diet, and of N in faeces, indicated that the cows grazing the LOW treatment were deficient in rumen degradable protein during the dry season. There was no interaction (P > 0.05) between the nutritional regime and the time of weaning on changes in conceptus-free liveweight (CF.LW) or BCS during the dry season. Weaning increased breeder CF.LW, relative to lactating breeders, by 0.42 kg/day in the early dry season (April–July; the difference between the W1 and W2 treatments), and 0.18 kg/day in the usual mid dry season (July–September; the difference between the W2 and W3 treatments). The NOCALF treatment cows were initially 79 kg heavier than lactating cows, and lost more LW during the dry season. Microbial CP synthesis was 21 and 29% greater (P < 0.05) in lactating than in non-lactating cows in the late dry season and shortly after the seasonal break (August and September), respectively. Calf growth was not affected (P > 0.05) by nutritional regime during the early dry season (April–July), but was lower for the LOW nutritional regime during the usual mid dry season (July–September); this indicated that the LOW nutritional regime cows mobilised sufficient additional body reserves to maintain milk production during the former, but not the latter, interval. All cows that were lactating at the commencement of the experiment gained CF.LW rapidly from September 1998 following the seasonal break. In conclusion, although nutrition affected LW change of both cows and calves, there was a much larger effect of weaning than of the nutrition treatments examined on conservation of body reserves in breeder cows during the dry season. The observation that the effects of weaning on conservation of cow body reserves were similar across a wide range of nutrition is important for management to achieve appropriate targets for breeder cow body reserves.


1989 ◽  
Vol 40 (5) ◽  
pp. 1085 ◽  
Author(s):  
MJ Mackinnon ◽  
DJS Hetzel ◽  
JF Taylor

Calving data recorded over a 28-year period were analysed for the effects of breed, filial generation, lactational status, cow liveweight at mating and year of mating. The herd comprised six distinct breeding lines ('breeds') and analysis was performed both within and across breeds. The least fertile breeds were the high grade (314-718) Africander (A) and high grade (718-purebred) Brahman (B) cows which had average calving rates of 56% and 55%, respectively. Crossing these with a Hereford- Shorthorn line, which had an average calving rate of 6O%, resulted in 19% heterosis (in absolute calving percentage units) in the F1 Africander-cross (AX) and 16% heterosis in the F1 Brahman-cross (BX). In subsequent generations, 13% residual heterosis remained in the AX, while in the BX only 1% remained. Reciprocal crossing of the AX and BX lines generated 6% heterosis in the Fl AXBX, and all of this was maintained in subsequent generations. In the F2 et seq. generations of the AXBX, the line of animals carrying the Bos indicus Y chromosome was similarly fertile (P> 0.05) to the line carrying the Bos taurus Y chromosome. Lactating mature (3 5-year-old) cows were on average 15% less fertile than non-lactating cows. This lactation effect was larger in younger cows. There was a curvilinear response in fertility to increasing liveweight at mating which was most pronounced in 2-year-old heifers. Breed appeared to react differently to the effects of environmental stress where the AX and HS cows were limited more by liveweight, and the BX and AXBX were more limited by lactation effects per se. Lactating cows that also lactated in the previous year were 6% more fertile than lactating cows that were dry the previous year, suggesting that calving records are moderately repeatable and therefore that permanent differences in fertility could be established by phenotypic selection.


2006 ◽  
Vol 18 (2) ◽  
pp. 116
Author(s):  
M. D. Jalinous ◽  
A. Niasari-Naslaji ◽  
F. Sarhaddi ◽  
E. Naghzali

Variation in estrous response is a major concern in estrus synchronization programs using prostaglandin F2�. The objective of this study was to confine estrous detection within two phases (48 h each) after synchronizing follicular wave emergence using ovarian follicle regressing (first phase) and ovulating (second phase) agents. Cyclic Sistani cattle (Iranian Bos indicus beef breed) at unknown stages of the estrous cycle and e58 days open were randomly assigned to two groups in mid summer. Females received a ration comprised of wheat straw (39%), Lucerne hay (28%) and concentrate (33%) that comprised 10% crude protein and energy at 2.1 Mcal/kg DM, according to NRC recommendations for beef cattle. In phase one, females in Group 1 (n = 33; heifers: 9; lactating cows: 4; dry cows: 20; 59 � 5.8 months of age; 361.2 � 11.5 kg LW; and 2.1 � 0.41 lactations) received estradiol benzoate (2 mg, i.m., Aburaihan Pharmaceutical Co., Tehran, Iran) and progesterone (100 mg, i.m., Aburaihan, Iran) followed by an injection of prostaglandin analogue (15 mg, i.m., Prosolvin; Intervet, Boxmeer, The Netherlands) and PMSG (400 IU, i.m., Folligon; Intervet) on Day 8. Females in Group 2 (n = 35; heifers: 9; lactating cows: 5; dry cows: 21; 59.3 � 5.7 months of age; 356.8 � 11.5 kg LW; and 2 � 0.35 lactations) received two consecutive injections of prostaglandin 14 days apart. In the second phase, starting 72 h after prostaglandin injection, females in both groups that did not exhibit estrus were given an intra-muscular injection of Gonadorelin (100 �g, Fertagyl, Intervet) followed by prostaglandin injection 7 days later. In both phases, standing estrus was recorded for 48 h, after prostaglandin injection, at 4-h intervals, 30 min each time. Within a defined period (48 h after prostaglandin injection) 12 h after standing estrus, females were inseminated with frozen semen. Pregnancy was diagnosed on Day 30 after insemination using ultrasonography. Data were analyzed using logistic regression and chi-square tests. There was no significant effect of parity and lactation status on the frequency of estrus and conception rates (P > 0.05). The total frequency of observed standing estrus throughout two phases for Group 1 and two females were 81.8% and 80%, respectively (P > 0.05). The conception rates from a single AI for Group 1 [1st phase: 70.6% (12/17); 2nd phase: 40% (4/10); total: 59.2% (16/27)] did not differ (P > 0.05) to that for Group 2 [1st phase: 66.7% (8/12); 2nd phase: 56.2% (9/16); total: 60.7% (17/28)]. The result of this study demonstrated that estrous detection rates of e80% can be achieved within 4 day observation period in Bos indicus beef cattle. The authors express their great appreciations to the Intervet Company, Holland and the Aburaihan Company, Iran, for kind provision of pharmaceutical materials to perform this experiment.


2011 ◽  
Vol 51 (6) ◽  
pp. 515 ◽  
Author(s):  
R. M. Dixon ◽  
C. Playford ◽  
D. B. Coates

The effects of two dry season management strategies consisting of timing of weaning and/or nitrogen (N) supplementation on the body reserves, nutritional status and reproductive performance were, commencing in the early dry season, examined in Bos indicus × Bos taurus breeder cows (n = 122) grazing native pasture in the seasonally dry tropics. Cows were early-weaned in April in the early dry season or late-weaned in September in the late dry season. The supplement consisted of loose mineral mix which provided on average 14 g N/day, principally as non-protein N. In the early dry season in April 1997 all of the cows had been lactating for 3–5 months, averaged 363 kg (s.d. = 28) conceptus-free liveweight (CF.LW) and 4.7 (s.d. = 0.6) body condition score (9-point scale), and 53% were pregnant. In addition, from April to June 1997 10/26 non-pregnant lactating cows, and 24/31 non-pregnant non-lactating (i.e. early-weaned) cows became pregnant so that 81% of cows were pregnant by June. Predictions of diet from near-infrared spectroscopy of faeces indicated that the forage diet selected during the dry season (April–November) by the cows contained on average 9% (s.d. = 2) non-grass dicotyledonous plants and 4.4% (s.d. = 0.38) crude protein (CP), while DM digestibility was 51.1% (s.d. = 1.3). The diet CP concentration, the ratio of CP to metabolisable energy (ME) in the diet (mean 5.7, s.d. = 0.53, g CP/MJ ME) and faecal N concentration (mean 1.05, s.d. = 0.097, % N) all indicated that unsupplemented cows were deficient in dietary N during the dry season. Microbial CP synthesis in unsupplemented non-lactating cows decreased from 360 to 107 g microbial CP/day, or from 6.5 to 2.4 g microbial CP/MJ ME intake, as the dry season progressed from May to September 1997. Net endogenous N transfer to the rumen of up to 2 g CP/MJ ME apparently occurred from May to August. Microbial CP synthesis was 25% higher (P < 0.001) in lactating than in non-lactating cows. From April to September cow CF.LW was improved by 0.35 kg/day (P < 0.001) by early weaning, and by 0.11 kg/day (P < 0.10) by N supplementation, but there was no interaction (P > 0.10) between these treatments. From April to June 1997 calf LW gain averaged 0.79 kg/day, but from June to September was only 0.10 kg/day in unsupplemented paddocks and 0.13 kg/day in N-supplemented paddocks. Pregnant cows calved from November 1997 to March 1998. During subsequent mating 96% of non-lactating cows, but only 17% of lactating cows became pregnant. During the 1997–98 wet season there was compensatory LW gain of lower CF.LW non-lactating cows but not of lactating cows. In conclusion, weaning early in the dry season had a much greater effect than a non-protein N-based supplement to conserve breeder cow body reserves, and the effects of the two management strategies were additive.


2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 58-58
Author(s):  
Megan A Gross ◽  
Claire Andresen ◽  
Amanda Holder ◽  
Alexi Moehlenpah ◽  
Carla Goad ◽  
...  

Abstract In 1996, the NASEM beef cattle committee developed and published an equation to estimate cow feed intake using results from studies conducted or published between 1979 and 1993 (Nutrient Requirements of Beef Cattle). The same equation was recommended for use in the most recent version of this publication (2016). The equation is sensitive to cow weight, diet digestibility and milk yield. Our objective was to validate the accuracy of this equation using more recent published and unpublished data. Criteria for inclusion in the validation data set included projects conducted or published within the last ten years, direct measurement of forage intake, adequate protein supply, and pen feeding (no tie stall or metabolism crate data). The validation data set included 29 treatment means for gestating cows and 26 treatment means for lactating cows. Means for the gestating cow data set was 11.4 ± 1.9 kg DMI, 599 ± 77 kg BW, 1.24 ± 0.14 Mcal/kg NEm per kg of feed and lactating cow data set was 14.5 ± 2.0 kg DMI, 532 ± 116.3 kg BW, and 1.26 ± 0.24 Mcal NEm per kg feed, respectively. Non intercept models were used to determine equation accuracy in predicting validation data set DMI. The slope for linear bias in the NASEM gestation equation did not differ from 1 (P = 0.07) with a 3.5% positive bias. However, when the NASEM equation was used to predict DMI in lactating cows, the slope for linear bias significantly differed from 1 (P &lt; 0.001) with a downward bias of 13.7%. Therefore, a new multiple regression equation was developed from the validation data set: DMI= (-4.336 + (0.086427 (BW^.75) + 0.3 (Milk yield)+6.005785(NEm)), (R-squared=0.84). The NASEM equation for gestating beef cows was reasonably accurate while the lactation equation underestimated feed intake.


1998 ◽  
Vol 30 (2) ◽  
pp. 227-243
Author(s):  
K. N. S. YADAVA ◽  
S. K. JAIN

This paper calculates the mean duration of the postpartum amenorrhoea (PPA) and examines its demographic, and socioeconomic correlates in rural north India, using data collected through 'retrospective' (last but one child) as well as 'current status' (last child) reporting of the duration of PPA.The mean duration of PPA was higher in the current status than in the retrospective data;n the difference being statistically significant. However, for the same mothers who gave PPA information in both the data sets, the difference in mean duration of PPA was not statistically significant. The correlates were identical in both the data sets. The current status data were more complete in terms of the coverage, and perhaps less distorted by reporting errors caused by recall lapse.A positive relationship of the mean duration of PPA was found with longer breast-feeding, higher parity and age of mother at the birth of the child, and the survival status of the child. An inverse relationship was found with higher education of a woman, higher education of her husband and higher socioeconomic status of her household, these variables possibly acting as proxies for women's better nutritional status.


2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Wen-Jun Li ◽  
Qiang Dong ◽  
Yan Fu

As the rapid development of mobile Internet and smart devices, more and more online content providers begin to collect the preferences of their customers through various apps on mobile devices. These preferences could be largely reflected by the ratings on the online items with explicit scores. Both of positive and negative ratings are helpful for recommender systems to provide relevant items to a target user. Based on the empirical analysis of three real-world movie-rating data sets, we observe that users’ rating criterions change over time, and past positive and negative ratings have different influences on users’ future preferences. Given this, we propose a recommendation model on a session-based temporal graph, considering the difference of long- and short-term preferences, and the different temporal effect of positive and negative ratings. The extensive experiment results validate the significant accuracy improvement of our proposed model compared with the state-of-the-art methods.


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